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General Category => General Discussion => Topic started by: czakky82 on May 18, 2023, 04:33:21 PM
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I’ve got my fairly fresh V7 Sport back up and running. It’s been fighting me pretty hard. You can say we’ve bonded. Crank is freshly re-ground, both mains and rod journals. Top end is also fresh, valves, guides, rod bushings, pistons, re-plated cylinders, etc.
I’ve got an annoying (don’t call it a knock yet) sound between 3500-4500 and it tapers off. Only on lazy acceleration, not when I’m holding steady or when I’m accelerating hard. I can’t re-create the sound when revving in neutral. Adjusting timing and valve lash has no effects.
I just had the top end off and could feel no permissible big end play.
It sounds pretty similar to spark knock without any performance loss (like a spray can rattle) although more rhythmic and not as fast as what I’d imagine a crank knock to be. It seems in rhythm to cam more than crank… if that makes sense. Loud enough to hear it with a full face helmet over valve clatter. It’s a slightly heartbreaking sound with no helmet…
Oil is clean (outsider filter) sump is spotless when dropped (old habits dies hard).
Any ideas? I’ll gladly wear earplugs.
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I’ve got my fairly fresh V7 Sport back up and running. It’s been fighting me pretty hard. You can say we’ve bonded. Crank is freshly re-ground, both mains and rod journals. Top end is also fresh, valves, guides, rod bushings, pistons, re-plated cylinders, etc.
I’ve got an annoying (don’t call it a knock yet) sound between 3500-4500 and it tapers off. Only on lazy acceleration, not when I’m holding steady or when I’m accelerating hard. I can’t re-create the sound when revving in neutral. Adjusting timing and valve lash has no effects.
I just had the top end off and could feel no permissible big end play.
It sounds pretty similar to spark knock without any performance loss (like a spray can rattle) although more rhythmic and not as fast as what I’d imagine a crank knock to be. It seems in rhythm to cam more than crank… if that makes sense. Loud enough to hear it with a full face helmet over valve clatter. It’s a slightly heartbreaking sound with no helmet…
Oil is clean (outsider filter) sump is spotless when dropped (old habits dies hard).
Any ideas? I’ll gladly wear earplugs.
Ok.
I had the same thing on my Norge at one point, only on certain throttle settings.
Clattered like hell.
Turns out it was the left side header tapping against a bolt head. I loosened the header studs and rotated the pipe outwards a couple of mm…Silence.
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@Huzo, I’ll add that I did isolate the side and center stands. I found one spot that the right side exhaust may be making contact though I’m not very hopeful…. I’ll have that squared away tomorrow (bike’s hot right now).
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Anybody have experience with bad rocker arm bushings? That’s the only part I haven’t replaced…
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How about rocker arm end-float? Are you using the OEM springs or thrust bearings?
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You seem to have good diagnostic instincts. When it’s rattling, does the noise alter with a gear change ?
It’s significant that you say that it doesn’t seem to be at the same frequency (not pitch), as the spinning flywheel, yet linked to rpm and load.
Why it dissipates with increased load is a vexing one.
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I had a weird noise on a cali, turned out to be the oil pump coming loose. I could hear it, took it to a few experienced guzzi mechanics who couldn't hear it. A few months later, full lock up when the pump came loose.
Obviously impossible to diagnose noises without hearing them, so just throwing it out there as an idea!!!
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What you describe with the engine in”float mode”,sounds like small end rod bushings. I replaced those on my eldo, and noise went away.
Rick
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@Guido, stock springs. Not familiar with any type of Guzzi thrust bearing… :popcorn: I’m very interested though…
@Huzo, gear change doesn’t have an effect. Low RPM high load: less noise, low RPM low load: more noise, high RPM high/low load: much less noise. The frequency isn’t consistent with lower end stuff but I’m not confident in that either.
I don’t think I’m a paranoid shade tree mechanic, but this is not a regular Guzzi sound either.
@lazlo, is that like oil pump drive/gear, or full on oil pump chewed itself apart? FWIW, oil pressure light goes off immediately on start up, stays off for a good bit even after running hot. So it feels like I have good pressure from pump to front of cam (oil pressure sending unit). Not that these are very accurate ways of measuring oil pressure.
Good insight for sure, I hadn’t considered oil pump issues….
How was your oil pressure when this happened?
@bigbike, that was my first thought too. Bushings are fresh, wrist pins (fresh) look pretty good. I can’t feel any play in them, the wrist pins will turn with some resistance in the bushings. The right does have a minuscule amount of less drag it seems. I don’t have means of accurately measuring the bushings, but I could still see cross hatching from machining.
This old bike hasn’t been babied FWIW.
I appreciate the responses. So thankful! I understand that it’s pretty hard to diagnose a sound over a forum so I appreciate any insight.
Cheers!
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What kind of clutch does it have?
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Engine mount and frame bolts all tight? I had an annoying rattle on my SR500 that turned out to me a loose engine mount bolt.
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My 1973 Laverda SF1 made some pretty distressing noise on throttle, I thought the bottom end was coming apart, as I stripped everything down to pull the motor the last thing I did was pull the exhaust off, the mufflers are held by two silent blocks which fell apart on one muffler as it was removed.
So my failing bottom end was a harsh vibration travelling through the muffler to the header joint.
I would take a serious look at all the engine / transmission mounting points, the foot rest / muffler hangers, the center stand mount bolts etc…..
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Have you tried listening ith a stethoscope? Or even a screw driver on an engine part and the handle end to your ear? You probably know all this I bet.
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So my failing bottom end was a harsh vibration travelling through the muffler to the header joint.
I would take a serious look at all the engine / transmission mounting points, the foot rest / muffler hangers, the center stand mount bolts etc…..
The top would be my number 1 place to look. I, too, had this on a long trip that worried me constantly.. :grin:
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How about rocker arm end-float? Are you using the OEM springs or thrust bearings?
EDIT: No one has suggested cam end float yet...
Gotta say that rocker arm end float is the least likely explanation offered so far.
But, since you asked
(https://i.ibb.co/cYn44WP/20230520-090531.jpg) (https://ibb.co/cYn44WP)
These thrust bearings take the place of the springs on the rocker arm spindle. Not sure on clearance between outer race and support bracket but .005" sounds right? Ace Mallott explained that the rocker arm won't lift the valve until the OEM springs fully compress. Timing is slightly retarded and full lift is never accomplished. Been running them in the ex convert for almost twenty years and have not seen any wear. YMMV
Nominal measurements:
OD: 28mm (27.80)
ID: 15mm (15.06)
Outer race width: 1 mm (1.03)
Bearing width: 2 mm (1.99)
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@Guido, FWIW I did pull the top end and while the pushrods were out I tried to feel for play in the cam and couldn’t. Not scientific or anything. Also my timing is as steady as any Guzzi I’ve ever seen. If cam float would show up at the dizzy…?
@John A, SD TEC.
Those bearings are sweet, I suppose I might need them…
Thanks again guys for bearing with me. :bow:
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What you describe with the engine in”float mode”,sounds like small end rod bushings. I replaced those on my eldo, and noise went away.
Rick
I had a knock on one of my Guzzi's that I assumed was a rocker valve clearance issue. Could not adjust it out. Said to my self, ride it. At a gas stop, a guy walked up and said, "you have a worn small end bushing worn out". He was exactly right. New bushings and the noise was gone.
The noise was at mid range rpms.
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What you describe with the engine in”float mode”,sounds like small end rod bushings. I replaced those on my eldo, and noise went away.
Rick
That was my first thought also. That that pin is a little sloppy in the rod or the piston. They seem to act up in that "float" range as you say.
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the securing nut on the oil pump gear came off. My buddy was riding the bike at the time, he ignored the oil warning light that was starting to flash on and seized the crank in the rear bearing.
I only mention this episode as it was a case of a strange sound/vibration that told me not everything was right but I didn't find it in time
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I was worried about the timing chain and found the front tire would grow at speed and rub the inside of the fender. I was looking and had the wheel off and was able to see the rub marks . It had me flummoxed till I found it alright and wasn’t what I expected.
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I’ve been riding this bike a bit and the noise hasn’t got any worse.
It is definitely coming from the left side. I can’t get the sound from neutral on a stand only under load.
I’m going to re-Torque heads for the second time. I’ll also switch rocker arms and pushrods from left to right and see if the noise follows.
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Yeah, switching the upper valve train made no change… Guido was right.
It’s running so dang good and smooth. Especially considering the carbs are only “bench synced”. I can’t justify tearing into it.
I’m mildly frustrated…
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Sometimes they just make noise without anything wrong. It’s one of the benefits of liquid cooling, it masks engine noise. My first Ambassador sounded like it was disassembling itself for a hundred thousand miles before and after I fixed the chrome bores and put everything right. Disappointing alright so I figured I would let it develop but it never changed over the years.
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That’s kinda where I’m at John. It runs fantastic, is smooth and it doesn’t appear to be any worse. I just kinda wish it wasn’t there…
Knowing myself I’ll probably go looking for it this winter.
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That’s kinda where I’m at John. It runs fantastic, is smooth and it doesn’t appear to be any worse. I just kinda wish it wasn’t there…
Knowing myself I’ll probably go looking for it this winter.
I have the same noise in the RH side of my '89 Mille. Barely noticeable when cold, annoying while hot. Took the top ends off, no detectable play anywhere. Next is to shim rockers and if that doesn't work, replace both ends of rods.
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Temp has no noticeable effect on this one. It’s just combustion chamber pressure apparently, or vibration.
It’s light throttle at 3500rpm and more throttle makes noise at higher RPMs until it tapers off around 5500rpm.
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I did find the source of a noise on my 99 Bassa. On the right cylinder where the cylinder protrudes into the case , the bottom of the cylinder just barely touches the back of the timing chest. I had the engine out and upside down and noticed a slight amount of aluminum paste where it rubbed. I ground some clearance and that irritating noise was gone. I wouldn’t expect to see that on the smaller bore engines and it’s only on the farthest forward cylinder, closest to the timing chest. I’ve looked on another 1100 engine and it was close but not touching but it’s something to look for when modifying for I think it came about when I deleted the base gaskets and used flange sealant as an easy way to set the squish which came out to .040” without the base gasket. Without the base gasket cushion it may make the fins ring a bit more but I couldn’t detect any . They have hard rubber bits about an inch long that stabilize the fins that Guzzi uses on some engines and I use those if I have them but I can’t hear any difference .
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Has nothing to do with the noise , but why not install an actual oil pressure gauge and put yourself at ease . There's worse things you could spend money and time on ! Peter
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Agreed Peter.
I had changed the oil and oil filter (aftermarket sump w/ filter) recently and kept the filter for an autopsy.
First time ever taking apart an oil filter. Not a spec in it hardly. A few specs of aluminum. So that’s encouraging.
I might just leave this one alone.
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Just curious- no idea what you wear for a helmet, but do you wear earplugs? It may help you better identify the sound. It’s not very scientific or expensive (Guzzi content) but if a noise changes significantly or goes away when I wear earplugs it makes me think differently about both the noise and the source.
And the more paranoid about hearing noises you are, the more you’ll hear noises whether there are noises to hear or not….
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After a total refurb of my 77 850 LM a couple of years ago it was making a seriously upsetting rattle and I was looking at stripping the motor again but needed to narrow down the cause of the noise to give me a clue as to what I'd done wrong and now needed to fix. Long story short, it turned out to be the new standard breather box I had installed to replace the old one which had rust flaking from inside, and followed the Guzziology recommendation I had busted out the flapper valve but the bits stayed inside the air box. When it sat in the 'normal' position it rattled like a bastard and when I tilted it backwards the rattle stopped. You can imagine my relief at finding that the noise was not the 'new' engine about to grenade!
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My 99 bassa had an annoying rattle around 3k rpm.Took me a while to hunt down.Turned out rattle was inside fuel tank.Tightend electric petcock half turn no more rattle. (Low fuel sensor?) Good luck!
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You guys are absolutely making me feel better.
@Nev, I too did the re-pop breather box surgery. Only because after a mildly spirited ride my Sport was marking its territory through the breather pipe. Checked oil, was down .5 qt. Since then it hasn’t puked at all. Still rattles though.
If I get ambitious this winter I might try real hard to track this down with some authority.
I just can’t find any symptoms that align with my own. Therefore I have to assume it’s in my head.
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After around 400 miles with new breather valve, I went for a ride yesterday. Started puking oil again, checked compression R 150, L 165 three squirts of 2t oil in each cylinder: R165, L 185psi.
Fresh pistons, rings, cylinders.
I didn’t think these were horrible numbers. I’ll do a pressure test this week.
Am I pressurizing the case that extremely with those numbers? :violent1:
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Roughly a 6% loss at 100psi, mostly through the exhaust valve…
Went for a 20 mile spirited ride. No oil dripping…
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It’s best to flog it without overheating it. It’s the fun part.
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I still seem to be pressurizing the crankcase. I’m still suspicious of the small end.
Are telescoping dial gauges a good way to measure wrist pin bush (22mm)?
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I’m diving back in. She’s coughing up oil through the breather and going through oil pretty good.
I see some specks on top of the pistons, these don’t look like pistons with 1500 miles on them, eh?
(https://i.ibb.co/XV2TVKw/IMG-5294.jpg) (https://ibb.co/XV2TVKw)
(https://i.ibb.co/x5pSj99/IMG-5298.jpg) (https://ibb.co/x5pSj99)
(https://i.ibb.co/fYRCvbp/IMG-5299.jpg) (https://ibb.co/fYRCvbp)
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Hi Bill, I am definitely not an expert engine guy but those pistons look more like they have 15,000 miles on them.
The brown around the top of the piston looks suspicious and the scuffing on the skirts reminds me of my race bikes when they were due for a rebore. What is the skirt to cylinder wall clearance? If it's to great that would allow the piston to "wobble" as it goes thru its stroke and cause a slapping or knocking noise.
I know this is a fresh rebuild and I am thinking the new rings are sealing well enough for the good compression but those pistons look suspicious.
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My gut reaction;
Your rings aren't well-sealed, supported by the dry/wet leakdown numbers. If you're using synthetic oil, drain it and get some cheap lawn-mower grade 30w. Run that for a tank of gas, run it a gear lower than you normally would; keep the RPM up but the throttle opening lower. When the rings don't seat, you get oil coming up past them, and you get combustion pressure blowing the oil off the cylinder walls and piston scuffing. Higher RPM will keep the walls well oiled, low throttle will keep the blow-by reduced. I don't mean to say don't load it at all, you need to get some pressure against the walls with the rings but not overheat. The cheap oil will help as you actually need a little more friction to get the job done. I put new Total Seal rings in my LeMans, asking them how to break them in- they said "Run it like you stole it". Back in 883 Racing days, iron cylinders of course, I used WD40 for assembly lube and on first start held it up to about 2500RPM until the cylinders were pretty warm to the touch. That got the rings broke in before the synthetic could keep them from it.
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more rhythmic and not as fast as what I’d imagine a crank knock to be. It seems in rhythm to cam more than crank… if that makes sense.
If it’s not every power stroke, then I cannot see how it can be in the engine internals.
Each power pulse is under identical conditions to the previous one.
Are you certain it is not rearward of the gearbox input shaft ? This is why I suggest riding it in the regime where it rattles and immediately change gear. If the noise stops, it’s in the engine.
If it doesn’t, it could be gearbox output shaft, UJ, or bevelbox.
How good is your camchain tensioner ? My Norge suddenly developed a non rhythmic type rattle and it turned out to be the pathetic spring had broken on the Valtek tensioner, hence the gears.
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@thunder, I’ll have clearances measured tomorrow. Stay tuned…
@pressure, that is uslful info. I’d never heard using straight weight before. I’m going to re-measure ring end gap, plus I have fresh rings. Total seal? Mine are Cabre(?).
@huzo, I’m fighting this thing on two fronts. Well many fronts actually for a few years now. This noise started with these pistons, cylinders. Which are new aftermarket pistons and re-plated nikasil.
Stay tuned ya’ll
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were the pistons matched to the cylinders or vice versa. When I worked in the radial engine aircraft shop we had to have replated cylinders ground to fit the pistons as new ones weren't available. Pistons had to be FAA approved, nobody would get them approved as the cost couldn't be recovered with so few in demand. We would recondition pistons and have the re-chromer grind the cylinders to size. Check your clearances, even feeler gauges will give you a pretty good indication of what you have.
kk
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@ mopar, yes the pistons were sent along with cylinders to millennium for re-plating.
I finally got around measuring piston to bore. I have .002” with the pistons I was running(“C” kit, GPM brand). The original OEM pistons (“B” kit) were about .0002” smaller. The cylinder is showing no wear. Next will be ring end gap and wrist pin bush just for piece of mind.
.002” clearance seems a little much for a 82.5mm bore.
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Ring end gap was good on the compression rings.
There is a good amount of carbon behind the top ring on both pistons. Is this a clue to anything?
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Sounds like there is too much clearance between the rings and the ring lands for carbon to build up there. I haven't re-read the thread but I don't think this condition would lead to any noise issues.
kk
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So ring lands to ring clearance is impossibly tight….
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So a pile of rings on my bench after being removed with a ring removal tool. I look and see a piece of about 1/2” piece of ring….
Pretty sure this is the source of noise, oil consumption and atleast some of the extra bonding I’ve been doing with this bike :violent1:
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:smiley: :smiley: Well, at least you found it.