Wildguzzi.com
General Category => General Discussion => Topic started by: Tom H on March 24, 2022, 05:34:33 PM
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Has anyone used or know of a good one that is not just snake oil? I'm trying to solve an on going problem with my Ambo 1000. Acts like a ping type problem. Thought a high octane fuel may tell me something.
I do have a VP Racing fuels gas station somewhat near me. I don't know what octanes they sell. Also, right now, I'm sure a gallon is very expensive. I would need at least 3 gallons.
So is there a booster worth trying a bottle of?
Thank you,
Tom
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Next step.... To find out why a stock 1000 roundfin wont run correctly at 4000rpm or above on pump gas in California. Maybe.... It has high compression pistons and I didn't figure that out???
This is kinda my last step with this engine. I wanted a freeway 75-80mph engine, I have a GREAT city bike. Sounds perfect below 4000rpm. I did start a thread about a year ago on the issues with this engine. Still have not solved it.
Except timing does change my noise issue.
Thank you!!!!!!
Tom
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Get the higher octane fuel from the pump. You'll be $$$ and performance ahead.
https://bobistheoilguy.com/forums/threads/octane-booster-and-why-they-contain-kerosene.186589/ (https://bobistheoilguy.com/forums/threads/octane-booster-and-why-they-contain-kerosene.186589/)
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Thought this bike sounded familiar . Guessing it has 1,000 CC Gilardonis installed , right , so it is not quite stock .
I would start with cam timing if you are sure the ignition timing is correct . What carburetors are you running , slides , etc . Unless something strange is afoot with the pistons being really high compression , if it is detonating the cause has to be a hot spot in one of the chambers , as 91 octane should be fine in a standard compression ditch pump .
Dusty
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The engine is from a SP or G5. "Should be" stock pistons, not Gilardonis 1000 in a 750 or 850. They are iron bores.
I would rather start another thread on what my issues are and reference my original thread about the problem with this engine.
I would like to keep this thread on a good octane booster. VP Racing Fuels has one that might work? $24 per quart, but only need 1/2 quart per 5 gallons.
If there is interest in the saga of this engine. I will start another post with the details of what I have tried.
Any thoughts on a booster?
Thank you very much!!!
Tom
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Never heard of anyone having success with octane boosters , and I've spent lots of time around hot rodders and racers.
Dusty
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104+ . The original booster and by all tests, the best.
PaulB :boozing:
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You might try some Chevron Techron as an additive. I have seen some air cooled engine intake valves so badly coated with deposits that they resembled a tulip bulb with the top half cut off. Before opening, the engine would lazily accelerate to 1/2 throttle and no more. Remove the carbs and boots, look inside.
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Add about 20% toluene to the gas….it’s a potent octane booster…. For you own info Google toluene as an octane booster
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Using octane booster every fill up will get old, fast. If it ran fine for years and then went south, octane is the least of your woes.
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I have had the issue ever since I put the engine together about a year ago.
I only wanted to try some as a TEST. If it makes a difference, then I find out why. If no difference, then I move on to other things.
Thanks again!!
Tom
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The purpose of octane booster or higher octane is to slow the burning rate of fuel on the ignition stroke through the first 45 degrees of the power stroke. This produces more energy for a longer period of time. Adding mineral spirits to your fuel would slow the combustion process. Or some two cycle oil.
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May be a bad wrist pin. A loose fit will cause a knocking sound that varies with rpm. Found this to be an issue with a Guzzi engine. I tried adjusting the valves and fuel changes. Some Smarty Pants Guy at a gas station walked up to me and said "sound like you have a bad wrist pin fitment issue" He was exactly right. New bearings and the problem was gone.
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If I run this engine at 65mph in 5th gear about 3500rpm. It's purring like a kitten. When I get to 70mph+ and 4000+ that is when the noise come in. If I "maintain" 4000rpm, but ever so slightly let off the throttle, it's back to being a kitten. Touch the gas to hold speed and back to noise. The noise will also clear up when going slightly down hill. Up hill or a headwind makes it worse.
Wrist pins and bushings are perfect.
It has been mentioned it could be a cam issue. Maybe out of time. I triple checked that the marks were line up on the sprokets. This is twice I've dealt with the sprokets. First install and when I changed to Valtec style tensioner.
Two stroke oil?? Hum.... I do have some of that. Would I mix it like for my outboard? 1/2quart per 6 gallons??
Thank you,
Tom
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If I run this engine at 65mph in 5th gear about 3500rpm. It's purring like a kitten. When I get to 70mph+ and 4000+ that is when the noise come in. If I "maintain" 4000rpm, but ever so slightly let off the throttle, it's back to being a kitten. Touch the gas to hold speed and back to noise. The noise will also clear up when going slightly down hill. Up hill or a headwind makes it worse.
Wrist pins and bushings are perfect.
It has been mentioned it could be a cam issue. Maybe out of time. I triple checked that the marks were line up on the sprokets. This is twice I've dealt with the sprokets. First install and when I changed to Valtec style tensioner.
Two stroke oil?? Hum.... I do have some of that. Would I mix it like for my outboard? 1/2quart per 6 gallons??
Thank you,
Tom
It’s sounds like you described it as making the noise when it in a “pulling” point, best terminology I can come up with. Or maybe when torque is demanded.
Hopefully not a naïve or dumb question but are you sure it’s coming from the motor?
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Not a dumb question.
I have worked on anything that could be rattling. Removed the horn and gen belt, anything under the tank tightened and adjusted, exhausts. Even went through the forks. Years ago my 850 had a rattle, springs were rattling. I have pretty much ruled out something rattling on the frame and bolted to the engine.
I had thought I fixed my issue. There was a weird vibration starting at about 65mph. Turned out to be the gen drive belt. It was a cogged style. The belt was hitting that lip where the upper belt cover bolt goes in. Removed belt. Vibration gone. Got a belt without coggs and all good.
Thanks again!
Tom
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One of the Guzzi mechanics can answer this question . You mentioned adapting round fin heads to a later motor . As per our private conversation where we discussed overall valve lift , are the rocker arm ratios the same between round fin later square fin heads ? Sorry for the sidetrack .
Dusty
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The heads, round to round fin. From '72 Eldo loop to Tonti 1000 round. Had to open up the push rod holes on the head.
EDIT: BTW the casing numbers on the heads are the same as well as the valves. Only difference is the exhaust header mounting and the hole for the push rod. Some latter loop heads even had the casting for the tonti headers, but the holes for the studs were not there. Don't know what the hole for the push rod was?
The rockers. If you mean the length of each arm from the center of the rocker pin to the tips for the valve and push rod. I "think" they are the same. DIFFERENCE... The Tonto blocks have the lifters located farther away from the piston bore compared to loop blocks. The rockers arm that goes to the push rod is angled upward to line up with the lifter. So yes that arm I think is longer, but from pin center line is the same.
I may be able to measure the lift. But only for comparison to the rest of the valves. I don't I have a device like a dial indicator to get book spec measurement.
Thanks again!!!
Tom
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You might be able to borrow a dial indicator , for that matter they are not expensive . Seriously , this thing is acting like it isn't breathing well above 4K , if the rocker arms aren't rocking far enough (hi-zoot technical term) it could be causing a problem .
You will get this Tom , we are all pulling for you .
Dusty
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I have renamed the thread to include why I was thinking of the octane booster. I would like to keep this to timing and fueling.
If this engine didn't run so well and quiet below 4000rpm, I would say I had a rod issue or the like. I really feel it's ignition or fuel.
I had mentioned that I can make the noise change with timing. Less timing quieter, more timing more noise and earlier in the revs.
While timing the bike in the garage, I over advanced the dist. to about 15-20deg. Idle was up and seemed to idle smoother. I kept that info in my mind.
If you were to time a '60's V8 for instance and didn't have a light, you would adjust the dist. to get it to start. Then you would turn it until you had the highest idle. When you put a light to it, you would be very close to where it should be.
On a test ride down a freeway that I to test on. I pulled off where I turn around to head home. Decided to adjust the dist. by ear like a V8. Engine started up fine. There is a hill right there, starting up on the short hill it was noisy, like I didn't know how to use a clutch. Got to flat ground and another start, not too bad. Got on the freeway and what a racket!!!! At the next exit I pulled off and getting to a parking lot to work on it was a very noisy experience. Put timing back to about normal and headed home.
I would love to put my ear next to the engine to hear where it's coming from. I don't think I can run fast enough to do it at 70mph :grin:
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I have renamed the thread to include why I was thinking of the octane booster. I would like to keep this to timing and fueling.
If this engine didn't run so well and quiet below 4000rpm, I would say I had a rod issue or the like. I really feel it's ignition or fuel.
I had mentioned that I can make the noise change with timing. Less timing quieter, more timing more noise and earlier in the revs.
While timing the bike in the garage, I over advanced the dist. to about 15-20deg. Idle was up and seemed to idle smoother. I kept that info in my mind.
If you were to time a '60's V8 for instance and didn't have a light, you would adjust the dist. to get it to start. Then you would turn it until you had the highest idle. When you put a light to it, you would be very close to where it should be.
On a test ride down a freeway that I to test on. I pulled off where I turn around to head home. Decided to adjust the dist. by ear like a V8. Engine started up fine. There is a hill right there, starting up on the short hill it was noisy, like I didn't know how to use a clutch. Got to flat ground and another start, not too bad. Got on the freeway and what a racket!!!! At the next exit I pulled off and getting to a parking lot to work on it was a very noisy experience. Put timing back to about normal and headed home.
I would love to put my ear next to the engine to hear where it's coming from. I don't think I can run fast enough to do it at 70mph :grin:
Tom, They do make a motor stethoscope that you can do that very thing👍
(https://i.ibb.co/Qr66ywR/E47-E055-C-65-F0-4776-B380-78-F7235-DF160.png) (https://ibb.co/Qr66ywR)
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Have you ever been on a freeway near L.A. Ca.? Can be scary!
Tom
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I ran Avgas 100/130 in a 50/50 mix with 93 unleaded in my LM3. Never pinged, has some lead in it. My brother did same thing and sent mix for a test, came back as 100 octane. He put it in his Triumphs. It does give you plenty of go. It helps if you live by an airport.
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The purpose of octane booster or higher octane is to slow the burning rate of fuel on the ignition stroke through the first 45 degrees of the power stroke. This produces more energy for a longer period of time. Adding mineral spirits to your fuel would slow the combustion process. Or some two cycle oil.
Slowing the burning rate is exactly opposite of what needs to be done.You need to speed up combustion to avoid detonation… Detonation is the spontaneous combustion of the end gases around the permitter of the piston. The longer the burn time ,the greater the chance for detonation…Octane boosters prevent the rapid uncontrolled burn, they do not slow down the burn of the main charge…..
https://www.youtube.com/watch?v=aH-lDh3rVFQ
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Hey Tom, just a thought but have you verified, with a light, that the timing is advancing fully to the full advance mark while at 4,000 plus rpms? Is it possible it has the wrong spring set in the distributor?
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I have worked with springs and full advance. I was working on slowing down full advance, but that slowed down low rpm advance. With a dual point dist. I put the heavy springs like used in a big valve head in it. Didn't help the noise, but killed the low end power.
I do run a single point loop dist. with stock springs from MG Cycle for a Eldo.
'Yes, either dist. will work as long as you change the dist. gear to match the cam gear.
Very good thought!!!
Tom
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Have you tried a compression test, maybe just some carbon build up. Short of pulling the heads and measuring the squish band to determine the compression ratio. I would start there, . A leak down may show a leaky intake valve which could be a cause of detonation due to a lean burn. Do you notice any excessive heat when winding it up?
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If you were to time a '60's V8 for instance and didn't have a light, you would adjust the dist. to get it to start. Then you would turn it until you had the highest idle. When you put a light to it, you would be very close to where it should be."
Wrong. That will be far too advanced. Find the fastest idle & then back off some.
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Octane boosters? Generally, 'No'. There is no way to predict or confirm your octane after you use it.
Whether it may be a diagnostic aid, well, perhaps. But it's not the path I'd take.
They do raise octane, but octane is a measure of speed of combustion; that tells nothing about contribution or detriment to power content in the fuel mixture. If your engine pings, and you add octane booster, and the ping resolves, you have some information to move forward with.
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This will start a fight , but octane isn't a measure of how fast or slow gasoline burns . Octane is only a measure of how resistant gasoline is to ignition . Gasoline can be blended to burn slightly slower or faster at any octane rating , although the differences are tiny . What chemists and IC engine designers are looking for are the conditions where the combustion process is complete at a certain degree of crankshaft rotation , low octane fuel ignites more readily , so in a high compression engine or in an old aircooled design that runs hot it can ignite too soon , meaning higher octane is needed to resist pre-ignition . Ethanol does tend to burn a tiny bit slower than gasoline , but that is a different discussion .
Dusty
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Pressure: As I have mentioned, I wanted to use the booster as a test tool. If it changes things, then find why.
Unfortunately no consensus yet on a good one to try :sad:
Lucian: Here you go. LH 150, 160 wet. RH 155, 160 wet.
The rings are new, maybe 100 or so miles on them. I pulled the heads apart while doing the rings. Guides, valves and springs measure in spec.
In a PM it was mentioned to check the cam lift. I did but I did not have the right tool and got some odd measurements, consistent, but odd.. A dial indicator will be here shortly and see what the lift tells me about the cam.
Thanks again so far!!
Tom
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This will start a fight , but octane isn't a measure of how fast or slow gasoline burns . Octane is only a measure of how resistant gasoline is to ignition . Gasoline can be blended to burn slightly slower or faster at any octane rating , although the differences are tiny . What chemists and IC engine designers are looking for are the conditions where the combustion process is complete at a certain degree of crankshaft rotation , low octane fuel ignites more readily , so in a high compression engine or in an old aircooled design that runs hot it can ignite too soon , meaning higher octane is needed to resist pre-ignition . Ethanol does tend to burn a tiny bit slower than gasoline , but that is a different discussion .
Dusty
Never start a fight before you do your research.
Octane is *not* 'resistance to ignition'. Octane is resistance to *detonation*. It is a critical distinction.
Gasoline can be blended for *great* difference in burn rate, and also for energy density.
'Pre-Ignition' is caused by hot spots in the combustion chamber, and is not very sensitive to octane.
'Detonation' is the *un-ignited* spontaneous combustion or explosion of the fuel mixture, caused by heat and pressure beyond the combustion threshold.
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Tom are you running the original vhb carbs? What size main jets? How are the plugs looking. I'm thinking it may be going lean at the higher rpms. Lean = more heat= more pressure = more detonation , Leaking valves can cause a lean condition also , do you have access to a leak down tester? I know you mentioned the valves measured in spec , but are the sealing properly? Thats all I've got tonight. All you can o is rule out the basics. I would also try plugs one heat range lower .
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Never start a fight before you do your research.
Octane is *not* 'resistance to ignition'. Octane is resistance to *detonation*. It is a critical distinction.
Gasoline can be blended for *great* difference in burn rate, and also for energy density.
'Pre-Ignition' is caused by hot spots in the combustion chamber, and is not very sensitive to octane.
'Detonation' is the *un-ignited* spontaneous combustion or explosion of the fuel mixture, caused by heat and pressure beyond the combustion threshold.
What do you think is causing the detonation ? The fuel is igniting , it is caused by heat , never said it wasn't . Trust me , I know the difference . Your statement that octane is about burn rate is wrong , that is what I was trying to sort out . Octane really is just resistance to ignition no matter the source .
Anyway , carry on .
Dusty
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You probably already did this, but: run the engine up to the condition where the trouble starts. Then see if one jug gets noticeably hotter than the other. If yes, you have taken step one to isolate the problem. If no, it lies in a system that effects both cylinders equally. Shade tree 101. Does the engine run cleanly up to high RPM in nuetral? Have you tried a new coil? The only octane boost I ever noticed a difference with on a tired engine was racing fuel from the local hot rod shop, or AVgas.
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More…this article was written by the head engineer of GM engine development…
http://www.contactmagazine.com/Issue54/EngineBasics.html
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RR: I'll give that a read latter today.
When I was working with my Dyna III. I found a real good site on coils and ignition parts. Long but good read.
Tom
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And it gets more complicated…The author of this forum response is chief engineer at a company doing advanced engine research
Re: High octane fuel burns slower?
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Post by David Redszus » Sat Jan 03, 2015 6:39 pm
jmarkaudio wrote:
I can tell you that it is possible to have a higher octane fuel that will evaporate at a lower temp and as a result burn faster than a lower octane fuel. So you can not assume one goes hand in hand with the other.
You can have a higher octane fuel with any number of boiling points and igntion points. They have nothing to do with burning faster.
Fuel octane values (either RON or MON) have NOTHING to do with combustion flame speed. They are completely unrelated.
If we run an engine on the dyno using straight “isooctane” (224TriMethylPentane) it would have RON and MON values of 100. Interestingly, there are actually 18 different isomers for isooctane with different octane values.
We could then add measured amounts of Tetra Methyl Lead(TML) to increase the octane values in steps. We would find:
TML
g/gal ........ MON .......... RON
0 ........ 100 .......... 100
2 ........ 108.6 ........ 108.6
4 ........ 118.0 ........ 118.0
6 ........ 120.3 ........ 120.3
While the fuel octane values are increasing, there would be absolutely no change in engine performance or in ignition temperature, flame temperature, laminar flame speed, peak combustion pressure angle and total burn angle.
Fuel octane alone does not change these combustion values. But a change in blend composition is another matter. It is possible to have two fuel blends with the same octane numbers, but they will behave quite differently in the combustion chamber. This is due to the fuel blend components and not to their octane values.
Different fuel blend components do have a substantial effect on combustion properties.
................... .................. nHeptane .... Methanol .... Toluene .... Isooctane
Laminar flame speed ................. 42.4 ....... 52.3 .......... 38.6 .........37.7
(cm/s)
A/F ratio for max FS .................. 122 ........ 101 ........... 105 ......... 106
(% of stoich)
Ignition temp ................... ........ 476 ........ 878 .......... 1052 ......... 874
(F)
Flame temp ................... ......... 3525 ........ 5050 ........ 3759 ........ 4193
(F)
Laminar flame speed is not affected by octane value but is a function of fuel blend components. Laminar flame speed is much too slow to burn properly in modern engines; chamber turbulence is necessary. When chamber turbulence (primarily squish velocity) is added to laminar flame speed, turbulent flame speed is the result. That is what will determine combustion burn angle, peak combustion pressure location, flame temperature and engine performance.
Laminar flame speeds are on the order of about 40cm/s (.4m/s). Squish velocity is on the order of 40m/s or about 100 times that of laminar flame speed. Combined turbulent flame speed would be 40.4m/s; the laminar flame speed having contributed very little to burn time or burn angle.
The ignition temperature of the fuel will determine the ignition delay period. The flame temperature of the fuel will affect the flame speed and combustion pressure.
It is most unfortunate that when race fuels are mentioned, even by fuel company marketing reps, octane seems to be the only fuel property that is mentioned. We very often find fuel company marketing reps to be very underinformed regarding their fuels. While every true race fuel refinery has fuel blenders and fuel chemists on staff, they are mostly kept out of sight and contact with race fuel customers. And the promotional literature is commonly written by some ad agency copy gal who knows only the buzz words and little else.
Fuel companies could provide real data regarding their products to help racers make the right decisions. But then, who would listen? :(
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The story.
I bought a complete but disassembled engine from a reputable Guzzi shop. I was told to assemble as is (bearings and all) and ride. There was slight confusion on rings, I thought he said don't change, but he said change. Compression was about 150 with the old rings.
I cleaned up everything. I replaced the big end rod bearings, timing chain (used the stock manual tensioner), seals/gaskets and the like. I was told all the bearings were perfect fitting. Since I was in there I did the big end.
I'm running VHB30's with 40 slides (also have tried 60's) V9 second notch, 50 pilot and 130 IIRR main (Guzziology recommended specs). Original non leaking floats with new needles. I do believe I also tried larger mains, but I don't remember what at the moment. I even tried another set of carbs, no change.
Started with a Loop single point dist.. Had my issue. Changed to Tonti dual point with Dyna III and stock pair of Tonti coils. No change and tried Busch Blue's. No change. Went back to single point. No change.
Changed to Valtec style tensioner and reconfirmed my cam timing marks as well as the flywheel TDC marks on my Loop flywheel.
Changed heads to a set of decent, not perfect Loop heads. Had to open up the push rod hole to use them. No change. Went back to Tonti heads. BTW: per specs the Loop and Tonti heads are the same except the exhaust header mounting. Casting numbers are the same. Even tried a good used set of rocker pins just in case there was an issue there. No change.
Recently I brought my cylinders and pistons to the shop. He said they looked oily. He asked about the heads and rings. He said he told me to change the rings. Now has new rings.
The Tonti heads. Pulled them apart and measured the valves and guides. Measured the guides with a 8mm ream. Perfect fit. Valves were all within the book specs. 3 on the high side and 1 on the low side. Measured at the tip and where it rides in the guide. Same size all the way.
I had thought my issue was a rattle. Checked everything, components, bolts, wires, stands, headers anything that could rattle. No change.
Right now I'm working on trying to figure out what cam I have without pulling it out.
Cam measurement question. Lift measurement and Guzziology. Is the lift measurement how much the push rod is lifted??? OR.....how much the valve is pressed down????
I read that cam builders rate the lift at the valve, not how much the push rod is lifted. DID I misread this????
If it is the push rod lift, and I'm measuring right. I possibly have a V7 Sport cam??????? BUT..... I am going to make sure that my measurement is correct.
If this engine sounds like it does under 4000rpm, when I'm over 4000rpm. This is the sweetest sounding engine I've had except my Hydro. I didn't put this in a Loop frame to have a great city bike. It was to be my go anywhere at up to 80mph. I can't do that with how it sounds.
The noise does seem to start at about 4000rpm. I have had it show up in lower gears at lower speeds. Harder to hear due to just general high rpm exhaust and the like noise. 5th and the freeway it's quiet enough to easily hear it. If I try to rev it in the garage, it either doesn't do it or I cant hear it. But remember, if I ever so slightly let off the throttle or go down a freeway slope at 4000+, the noise goes away.
Trying a booster was a thought on how to see if it was ignition. Maybe lean?
Thanks again,
Tom
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Time it w/timing light at 2*, like a stock smallvalve 1000 round barrel. Still make noise? Jet your carbs.
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I played with the cam lift again.
(https://i.ibb.co/SBFpSry/cam-lift.jpg) (https://ibb.co/SBFpSry)
If I'm doing it right by measuring from the lowest part of the lift to the highest part. I get a consistent .270"-.272". In the photo I tried measuring a bit different and came up with .275".
I always tried to find the lowest point on the cam. Then zero the gauge. The .275". I found the highest lift, rotated crank 360deg (S/B opposite the high end), then rotated 360deg again to the high. Now I'm pretty sure I have it right. Rotated 360 again to the low, zeroed and measured.
If I'm reading Guzziology right and measuring right, I have a 750 S cam.
Please correct me if I'm measuring wrong!!!! The only other thing I can try to confirm this is with a degree wheel. Would need to get one.
Tom
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After making sure I was reading the lift right, it looks like Guzziology numbers are when you have the cam in your hand and measure it.
I borrowed a stock cam and measured the lift with my dial indicator. It matches the lift with the one in my bike. So it's not likely a cam issue.
I've run out of ideas. I will work on jetting again and see what happens. If that doesn't solve it. I'll run it until it breaks, then I'll know what it is.
Thank you,
Tom
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Re torque heads , adjust valves , sync carbs and try again , Pull plugs and inspect , adjust jetting accordingly , A cooler plug will sometimes help with detonation. Assuming you are running stock heat range.
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I suppose it's nothing simple like an air leak or lean carb condition? Ignition timing or weak spark?
I shouldn't comment because I am so inept. :sad:
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Plugs: Tried 1 number hotter and colder. Even tried platinum and iridium.
Dist.: Loop and dual point with Dyna. No change with either. Also different wires and I think caps. I might try caps again, but I doubt it.
Wanted to mention. I did try the choke while it was making noise, no change. Cam timing. I did use a degree wheel and the 1.5mm valve clearance spec for this engine and the timing was "almost" spot on. Exhaust was perfect, intake off about 3 degrees open and close. If I was off just a tad on the clearance, that will change the timing.
Thank you again!
Tom
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Want to buy a set of base cyl shims, got a set years ago from Harpers. I'll never need them again. Finding them might take awhile.
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Busted valve spring? Hasn't been mentioned here. My Lemans IV had a high rpm tapping noise. Found an inner valve spring was broken. Previous owner might have missed a shift...
Larry
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retard the timing richen mixture and or install the shimes under the cyilnders the shimes work like a champ you will have a much nicer running engine. I have done it on a eldo . I used .062 aul shim. You will loose a coupel hourse power at the dineo at wide open throtle when are you ever running down the road like that.
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Springs are in spec. Bought a scale to test valve springs.
Tom
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Tom,
The next diagnostic would be to discover some timing points. Idle, 2000, 3000, 4000. Perhaps the curve is simply too fast for the dynamic compression; My LM1000 has about 155psi with a Web 86b cam, and the difference between a bit of rattle and none detected was a new set of advance springs as the stockers had relaxed and worn the ends a bit. Even then, there's a bit of wear in the weight holes, so the point of entry for the heavier high-RPM spring is a few degrees late- that is to say, it doesn't control the timing until ~3* later than it might if everything was new. These are very small differences, but they do matter. So, you might simply try installing a set of LM timing springs and see if it keeps things under control. Otherwise, you could retard the timing 4*-6* and do some mid-RPM testing though your idle and top end will suffer and you don't want to keep it there beyond testing.
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This noise has followed two Dist..
Single point and Bosch blue: Two loop springs as well as the loop loop and loop oval. No change.
Dual point with Dyna III and Bosch blue: Stock springs and LM Type that hold the advance down. Thought holding the advance down might solve it. Stock springs make it run better off the line.
I have timed it at 2 degrees AFTER TDC. The noise was almost gone, but so was performance.
As I mentioned. If I advance the timing to lets say 10deg., the noise comes in earlier in the RPM range. Retard the timing, less noise.
So if it's a mechanical issue.............. What could it be that timing would effect? Rods: small end perfect and I believe big end as well. Rocker arms?????
Again, if I float the throttle (just a hair off throttle, no gain, no significant loss of speed. Like holding speed on a small down hill), noise GONE. Get back on to hold speed, noise again.
Thank you!
Tom
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I have a '68 Dodge Charger, with stroked 440. I built the engine with driveability and economy in mind; it's perfect but for one thing. To my dismay, I discovered what modern engineers had known for a long time; the engine wants 18* timing at idle, and 12* at 2000rpm. So I find myself fighting a cruise tip-in rattle if I feed too much throttle. This is an artifact of the mechanical distributor, and most of the reason they went to electronic timing. It's possible that your engine is simply tight enough that the dynamic compression is too high, and your only hope is to hold the timing down at idle spec until you get past the part where it rattles. I assume you've carefully checked both cylinders? I find the timing harder to set on the dyna than on points. I don't know what cranking compression is stock for you, so can't say whether raised compression is an issue here. Is the noise clearly only on one side, or both? You could also try installing spark plugs a range or two colder, as an inexpensive test.
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dubble plug it or you could use water injection. it will work or you could lower the compresion with the shims. Or as you stated just hold it where it is knocking and achive a dynamic disasembly. That is what my freind Rick did in the laverda 750 sf I sold him, I do refer to him as ricky retardo, Held it in 5th gear 40 mph. Gave him a ride on it before he blue the top off the left piston And it did not knock. he could not get it I told him to shift down. Hey what do I know,He did get to stop knocking. I did put gt pistons in it for him runs great ,I got it back a bout ten years later.
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could there be carbon build up on piston or combustion chamber?
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if I ever so slightly let off the throttle or go down a freeway slope at 4000+, the noise goes away.
That sounds like rod bearings to me.. (shrug)
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Rod bearing. When I bought the engine, I was told both rod bearing were perfect as well as the fit to the pin and crank. Is a maybe, but don't think so?
The question again. Would increasing the advance make the noise of a rod bearing show up earlier in the revs? Decreasing advance make it latter.
And again, at about 3500/65mph, the engine is perfect sounding. If this were the days of the 55mph speed limit I would never have known there was a problem. If I wanted to stick to 65mph and under, I would do a round trip across the US in a heartbeat. It sounds that good.
Also I had the heads off recently, just needed to wipe off and a little wire brushing of the piston and head. No real build up.
Thanks again!!!!
Tom
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Rod bearings are usually noisy on the over run…..Tom says he applied the choke and no change? Fattening the mixture that much should eliminate or at least lessen part throttle detonation…
if you have not tried high octane fuel yet now is the time to do it…..And what you describe ,regardless of new parts ,sounds like loose piston pins….
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Rod bearings are usually noisy on the over run…..Tom says he applied the choke and no change? Fattening the mixture that much should eliminate or at least lessen part throttle detonation…
if you have not tried high octane fuel yet now is the time to do it…..And what you describe ,regardless of new parts ,sounds like loose piston pins….
Yeah, rod bearing/pin. Hard to say over a computer. :smiley:
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So your saying that the rod bearing can be quiet at 3500rpm and make noise at 4000rpm on a steady throttle? Would more or less advance change this?
Thanks!
Tom
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So your saying that the rod bearing can be quiet at 3500rpm and make noise at 4000rpm on a steady throttle? Would more or less advance change this?
Thanks!
Tom
No. They make noise when the load is removed, even a smidgen. (technical term)
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No. They make noise when the load is removed, even a smidgen. (technical term)
Then it appears not to be a rod bearing. If I let off a "smidgen" it's a quiet as a church mouse. Back on a "smidgen" and the noise is back. Drop down from 4000rpm to 3500rpm and hold, and the noise is gone.
This would make a great city engine, I was after an engine for the open road.
Thank you again!!!!
Tm
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I guess drain gas tank get a gall of high octain race gas. ride it if no change well its mecanical I did have a few pushrods come apart steel ends com loose easy to check. other wise wrist pin bush to check rock wrist pin back and forth. If it is the bushings what I would , did do install bushings and have them borerd so both centers to center are the same. also it is the absolut best surface finish.
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I did check the push rod ends. They feel tight, could not move them with my fingers. I checked the small end pins and bushings when I put it together originally. They do not rock at all. I may be pulling the heads again, if so I will check the pins and bushings again.
I wanted to really thank everyone who has made suggestions!! :bow: :bow: I have tried many of them already, but always worth being reminded to check, even if I do the check again.
This is just a really frustrating issue. If it made the noise at ALL RPM, then it would be easy to find the problem. It sounds perfect, until I get to right about 4000rpm and then above.
The only constant thing that makes any changes is to retard the timing. Yes, I have made sure the timing marks are correct so many times hoping that I would find I didn't get it right. Even if the arrow on the fly wheel was off a bit from the factory, I have also checked TDC with a chop stick in the spark plug hole. All marks line up right with the stick.
Thank you ALL very much again!
Tom
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I chased a "mechanical vibration" for entirely too long. Eventually balanced the rotating assembly, etc. Nada. I became really good at crabbing that sucker. Eventually found it was a tweeked crash bar that was doing some kind of sympathetic vibration at a certain rpm. :rolleyes:
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Chuck, I have looked for that type of thing. I will keep looking just in case.
I even pulled the front end off. Years ago I had a rattle in my Ambo or Eldo. Turned out the fork spring was rattling, I think?
Tom
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At some point, you look at everything and say 'nothing shows damage' and drive on as is. Crash bar vibration, fork spring vibration, alien elves- all these things are possible and impossible to discover so if it ain't hurt, it ain't hurt.
As a last simple check, it is unlikely but possible that it's a lean condition; check that the needles in both carbs are in the same slot, if not raise the low one. If they are, raise them both one clip and see if it helps. <shrug>
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etc.
Nada. I became really good at crabbing that sucker. Eventually found it was a tweeked crash bar that was doing some kind of sympathetic vibration at a certain rpm. :rolleyes:
Sorta like "aerodynamic", flutter..ha!...BTDT!
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I'm not mechanically inclined but what I keep reading in the two year saga is the same suggestions over and over, the same results over and over, and no improvements. At this point the problem solver in me says it's either the most obscure possible condition in the engine or it's not the engine. I lean toward the latter.
One thing I see over and over is that your noise relates to rpm. You've created it in various gears but at the same rpm. That also means it's not a speed issues. So maybe the timing is a red herring.
So what if you focus on rpm not timing? Where does that lead?
-AJ
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Sorta like "aerodynamic", flutter..ha!...BTDT!
Lucky you lived through that one.. :shocked: :smiley:
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AJ, you made good points.
I decided to buy the Lucas octane booster. I'll take the bike for a ride in the next few days and see if it did anything. If it did, I'll be hitting up Steve for his spacers.
If it didn't. I'm going to pull the cylinders and rods. I'm sure the rods are straight and the bearings are fine. But I will check them again. Maybe I'll install the spacers while I'm in there if I buy them.
Then if I don't find anything and the noise persists, I'll pull the POS, grab the useables, and dumpster the rest. Maybe grab a 1100 or just put my 750 back in. At least my 750 would roll along at 70. Though it always seemed like it was revving high compared to my Eldo.
Thanks,
Tom
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So here's where I'm at.
Added the Lucas Booster. Mixing ratio was a bit confusing. No clear instruction on bottle except that it treats up to X gallons. I went with the ratio on O'Rielly's site. 1oz per gallon. Full tank added 6oz.
Seemed peppier, probably just me?? Went on one of my freeway test tracks. One way has more flat to downhill, back is more flat and uphills. Timing was at 2deg.
Going: "Almost" seemed like less noise. Ran as usual. Hold throttle flat to uphill, noise. Downhill, noise gone.
Coming: I "think" the noise was worse than before the Lucas. The kicker was when I got off the freeway and about 2 miles of city, I stopped at a store for a few minutes. When leaving I felt like I wanted to get up to s[peed a little more briskly than usual for S+G's. Right about at my shift points for 1st through 3rd the noise was there and loud, only need to go to third and then turn to a side street. WTH!!!
Day 2: Adjusted timing to 0deg. Ran the same route. Much quieter, but noise still there. Stopped at the same place on the way back and tried to pull away like I did the day before. No noise this time.
I think I'm may just to have to give up on it for now. If I want to do a road trip it will be my EVT or HD. Both will roll along at 70+ all day. The HD will do 80+ all day.
I just don't get why at 65mph/~3500rpm or less it sounds PERFECT!!!!!! Just FN PERFECT!! Going slightly downhill holding 4000 RPM it sounds PERFECT!! Ever so slightly let off throttle on a flat or uphill while still at 4000, PERFECT!! Roll back in the tiny bit, BAD AGAIN. But get a hill or a headwind on a flat, it sounds like something like a valve is going to come apart.
I also wanted to say that the sound is NOT the typical "ping". My Eldo 850 does get the "ping" like popping/ breaking glass (probably needs a decarb after 15 years or more and who knows how many miles).
There was an offer for the spacers and a mention of that it helped. I'll PM to see if the offer is available. Then when I'm in the mood to install them, I'll see if the spacers fix my problem. Since the jugs will be off, I'll look at both ends of the rods.
Well, thank you all very much for all the suggestions. I have been chasing this for WAY too long.
Tom
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Excessive glowing carbon deposits on the piston crown can lead to pre ignition. It can fire the mixture too early.
This is different to detonation, which is the uncontrolled burn rate of the mixture.
If you have an excess of carbon causing the ping, it will generally reduce or cease when you roll off the throttle, thus reducing the CHT...(cylinder head temperature).
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Huzo,
The 1000 was opened and cleaned many times. There has been no carbon build up while I have been trying to solve my problem. My 850 could be carbon build up.
Thanks for the thought!
Tom
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Huzo,
The 1000 was opened and cleaned many times. There has been no carbon build up while I have been trying to solve my problem. My 850 could be carbon build up.
Thanks for the thought!
Tom
Our little postie bikes used to routinely need a piston de carbon at 16,000 k.
They would ping their gutses out in hot weather until it was done.
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I'm thinking that is my 850's problem. It's on my list of "to do's" and have head gaskets ordered, may have new valve guides done since I have the heads off.
Tom
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Don’t give up, I’m I a similar situation and it feels shitty. With that said, can you measure spring pressure? I wonder if it’s valve float.
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Don’t give up, I’m I a similar situation and it feels shitty. With that said, can you measure spring pressure? I wonder if it’s valve float.
It probably doesn’t help, but people here care...a lot.
I am really looking forward to the wash up on this. I did two back to back Melbourne-Sydney runs this week in the truck.
1000 km each way=4,000 km and I was thinking of your issue a HELL of a lot of the time.
Each time I stopped for a mandatory rest break, I checked the forum and although your side of the world was in night time darkness, I was amazed at how many replies you were getting.
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I've read all the posts here I didn't see anything that indicated that you actually check the advance Springs it may be stretched and it doesn't come into effect until you write that 4000 RPM range which would probably be full Advance on your engine anyway just a thought
TOMB
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Tonti heads springs: Bought a valve spring gauge and tested the springs per the Guzzi manual. This gauge you mount in a vice or arbor press and then measure the length of the spring per the specs in the manual and read the pounds. All tested maybe 5# less than the max spec in the book. Seemed acceptable to me. Also checked the installed spring height, provided I did that right, hoith was fine. Also spring free length was correct per the book.
I was thinking valve float as well, that is why I tested the springs.
Dist. springs: I do not know how to "test" the strength of the springs. I would guess the only way is to watch how the timing advances per rpms.
Dual point dist. W/Dyna 3 and Bosch Blue: Used set of stock springs as well as new performance (fitted mainly to big valve engines, slows the rate of advance) springs. Neither set fixed my noise when timed at 2 or 0 deg. Performance springs caused a loss of power in the low end but did hold back full advance until over 4000 rpm.
Single point dist.: Used set of standard springs from Harpers both loop/loop, don't remember the coil count. Also tried a new standard set from MG Cycle, 1 loop/loop and 1 loop/oval. No change with either set. Low end power was fine though with either set.
Guzziology has a nice chart of advance curves with different springs. Tried the performance springs because it would hold down full advance until about 4200 or 4300, can't remember which.
The closest I have come to eliminating the noise is with the timing at 2deg After TDC. I lost a fair amount of power this way.
Lets also see: New plugs (BP6ES or BPR as normal, BP5 as well as 7), 2 sets of wires as well as end caps. A used Tonti small coil set as well as new Bosch blue with the dual point.
I have tried to find ANYTHING and everything that could be vibrating. Nothing, except I found my gen belt was rubbing the upper belt cover mount. Even removed my horn and gen, went through the forks, put my foot on the side stand, ect..
Also thought it might be a crack in my headers or exhaust leak at the gasket. Using Tonti heads with Loop headers and 2 gaskets, tried to sets of headers. Changed to Loop heads and 2 sets of headers. No change.
As a refresher, I do have the valtec type chain tensioner and a new cam chain. Also made the noise with a stock manual adjust tensioner.
This is why I feel I'm over it. There is a noise coming from somewhere caused by something. Timing affects the noise, but could also change how the engine naturally vibrates I would guess. More timing more and earlier noise, less timing less noise. I really don't want to run at 2deg Atdc. Nor do I feel like tearing the engine down to a bare block and still not find anything.
Yes, I have made sure my marks are correct every way to Sunday.
Even thought I could have the wrong cam. Took a degree wheel and followed the book on how to check valve timing, should be the correct cam. Also tried to check valve lift with a dial indicator. I compared my lift to the lift of a correct for this engine used cam. They matched.
At some point I will try the cylinder spacers. and see what happens. If it doesn't fix it, does anyone want a great 1000 engine for a city bike :evil:
Tom
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I added the spacers and times it at 2deg. Went for as short test ride and it may have helped a bit. I need to do my longer test tracks to know how much of a difference it actually made.
I also looked at the rods since I was in there. I do not have a real good way to measure the small end ID. Removing the piston and just using the wrist pin, it felt fine. I could not feel any slop. I don't think I wold have measured accurately enough to tell how much wear they had. My 850 had wrist pins you could wiggle, I don't believe it made any noise. At least not like the 1000 does.
I also confirmed again that if I keep it at about 65mph in 5th or less, it sounds great. I would guess that's about 3500rpm. On the streets in lower gears and about that rpm, it sounds great as well. I guess that's why I could never understand a rod end being bad. Seems like it would act up at any rpm? (shrug)
Tom
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I would think w/shims at .020" it would not have any ping from ign. Your squish just got bigger. I'm not a math & science guy but maybe 8 1/2-9 to 1 comp.
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Another thing:
Have you checked your fuel petcock/filter?
Could be that you're running fine at small throttle openings, but
lean at larger throttle openings. could be making it ping?
Just a thought.....
Please keep us informed - I'm really curious!
-Stretch
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Maybe it's not engine noise but transmission.
-AJ
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Took it out on my test track today. I do think the shims helped, about 75% or so better...SO FAR. More riding needed to confirm this.
Fuel idea isn't a bad one. I don't think they are clogged. The in-tanks are fine, might look at the carb filter. I had been running a universal inline filter. Removed it since I was thinking the same about running lean. I did try one time running on both petcocks, didn't change the noise.
Thought about the trans.
As I have mentioned, more timing = more noise. I'm at 2deg since adding the shims. I think if I adjusted it to 0deg, the noise "might" be completely gone. I need to ride a bit more and see how it does.
Thank you all again for the thoughts!!!!!
Tom
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Maybe you just need better better plugs. :boozing:
-AJ
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Ear or spark?? :boozing: :whip2:
Tom
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Damn autocorrect. Maybe you need better ear plugs. 😀
-AJ
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Did it blow up yet Tom? Just wondering what happened on more miles.
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Welllll..... I need to ride it more. After installing the shims I thought it had improved it on my first ride with them. Then on the second ride in warmer conditions, seems like it didn't make a difference.
I have been riding my 850 Eldo. The 1000 has more low speed power, but I could swear that the 850 has more get up and from ABOUT 65mph. No dyno data to prove it, just my feeling.
I'll ride it more and see. Right now I think it will make a nice city engine compared to my 750 Ambo with the 4 speed box. Always hated the 1st to 2nd shift of the 4 speed.
I love my EVT for how it runs. It "should" be my long distance bike. I had a tip over in a parking lot a while ago. I had to have help to pick it up, at least to do so quickly. Maybe I need to make my Tavern to Tavern "style" HD my long distance bike. It's low CG makes me think it I did tip over, I could pick it up.
AAARRRGGGHHH,
Tom
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Now that I had my rant.........
I do need to ride it a bit more to confirm how it's doing. Right now, the shims didn't make a significant change.
I think I'm down to the point of having to pull the engine apart and take all the bit's to a "specialist" engine builder to check and measure all the parts. But in reality, I don't want to spend any more money on it.
But again........ If I had an issue with a "part", I would think the issue would be there below the 65-70mph range as well as above. As I have mentioned many times. If I keep it at or below 65mph/4000rpm, it runs really nice and sounds really nice.
Thank you all!
Tom
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OK