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General Category => General Discussion => Topic started by: mneumann on May 06, 2020, 08:26:56 PM
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Hi there,
Hopefully this is the last question for awhile- I have been trying to get the timing correct on my G5 and am running into some issues. When I look at my flywheel I only have 3 marks. I have the D, S, and Arrow. It seems to be missing the two lines that go above the D and S. Has anyone encountered this? What is the best way to go about timing it?
I was thinking if I knew where the lines are suppose to be degree wise it would be easy enough to find TDC and then use a degree wheel on the front of alternator to correctly mark the flywheel and set the timing..?
Currently the bike is running pretty good but the right cylinder is running hotter than the left. I played with the carburetor setting and this did not effect it. I also just recently set the valve clearances to the .009" specified in the manual. This is what is leading me to think that the timing is the culprit.
As always any suggestions on how to proceed are welcomed.
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I would use a probe in plug hole for absolute TDC, should correspond w/flywheel marks. Then do the degree wheel on front. Arrow is for flywheel exposed, Lines up at centerline of cylinders for marks on the side.
AND yes I have seen those marks missing on a 850T. AND much more.
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put a straw in the right cylinder, revolve the alternator nut until the straw hits TDC, Take a marker on the alternator fin at 12 o'clock postilion (D side). Then the left cylinder will hit TDC at 3 o'clock (S Side).
Check the valves for clearance, you could be one revolution (360 degrees) out. (same as the timing marks)
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Once I find TDC how do I know where the static timing mark and advanced timing mark go? Is there a certain degree before TDC that they belong at?
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It sounds like your flywheel has the “D” and “S” marks to indicate TDC on the right (D) and left (S) cylinders, but no marks which would indicate when the plugs should fire in advance of TDC.
If that’s the problem, the solution is a “dial back” timing light. Like this one:
https://www.ebay.com/itm/Vintage-Snap-On-Tools-MT241A-Timing-Advance-Light-Used/124178570586?epid=1822147433&hash=item1ce99e9d5a:g:UmUAAOSw~y5eszsa
If the advance you want is, say, 10 degrees at 2000 rpm, you set the knob on the light to 10, rev the motor to 2000, and point the light at the flywheel mark. If your timing is correct, the light will flash at the TDC mark.
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So for as I know D and S are respective TDC for the left and right cylinder used for marks to adjust the valves.
I find marking the alternator fins an easier process. If you can can see the D and S timing marks, you're good to go. I still like the marker since it's much easier to see.
Have no clue about timing advance and ignition timing.
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Yes the D and S do mark TDC. Not sure how precise they are but they’ve worked well enough to get it close. I just figure if I’m going to put new marks I might as well check.
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If the advance you want is, say, 10 degrees at 2000 rpm, you set the knob on the light to 10, rev the motor to 2000, and point the light at the flywheel mark. If your timing is correct, the light will flash at the TDC mark.
That makes sense. Do the rpms need to be accurate for this? The bike doesn’t have a tachometer either. :violent1:
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The owners manual has the G5 ignition fully advanced at 31-33 degrees BTDC. When rebuilding my engine I checked the flywheel with a degree wheel and a dial indicator on TDC. The fully advanced marks were not only a little off, but also very lightly marked and hard to see. I filed new marks with a small triangular file and then painted all marks. Not really worth doing unless you have the gearbox off.
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S=sa lefta side.
D=datsa da right side.
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So for as I know D and S are respective TDC for the left and right cylinder used for marks to adjust the valves.
I find marking the alternator fins an easier process. If you can can see the D and S timing marks, you're good to go. I still like the marker since it's much easier to see.
Have no clue about timing advance and ignition timing.
D = Destra (Right)
S = Sinistra (Left)
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This is from Guzziology. it doesn't list the V1000, and there are three variations 1. V7 Sport 2. 850T LM 1-5 & big valve Cali III 3. T5,SPII Mille GT, small valve Cal3, late S3:
#1: Right TDC to the Static Mark = 26mm
Static to Full Advance = 52mm
Left Full Advance to Right TDC = 102mm
#2: Right TDC to the Static Mark = 16mm
Static to Full Advance = 52mm
Left Full Advance to Right TDC = 112mm
#3: Right TDC to the Static Mark = 4mm
Static to Full Advance = 62mm
Left Full Advance to Right TDC = 114mm
The flywheel is 722.5mm circumference, 2mm = 1 degree Rotation.
You can also determine distance by ring gear teeth. Divide the number of teeth by 360 and you've got it. There are 96 teeth, which works out to 3.75 degrees per tooth.
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D = Destra (Right)
S = Sinistra (Left)
To be pedantic and more correct, Italian nouns have 'gender' and their adjectives must agree with that gender. So, if we are talking about the 'right side' our adjective will change. 'Side' is a masculine gender noun 'lato'. The adjective becomes 'Destro' with an 'o' rather than 'a'. 'Lato Destro' = right side. The spark plug or 'candela' is a feminine gender noun. The right spark plug or 'candela destra' resides in the right side of the motor 'lato destro'.
Patrick Hayes
Fremont CA
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Even easier to remember, when translated into 'merican:
D = driveshaft side
S = starter side
Howard
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Dis side
Snot dis side
:cool:
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LOL - where'd you come up with that one, Chuck? :grin:
I remember it this way - Dexterous is probably derived from Destra. Most everyone is right handed, and not dexterous with the left, therefore...
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Dexterous is probably derived from Destra. Most everyone is right handed, and not dexterous with the left, therefore...
And left, sinistra/sinistro leads us to sinister because left handed people were perceived as evil.
Patrick Hayes
Fremont CA
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Nah....Frank might have been left handed.....
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This is from Guzziology. it doesn't list the V1000, and there are three variations 1. V7 Sport 2. 850T LM 1-5 & big valve Cali III 3. T5,SPII Mille GT, small valve Cal3, late S3:
#1: Right TDC to the Static Mark = 26mm
Static to Full Advance = 52mm
Left Full Advance to Right TDC = 102mm
#2: Right TDC to the Static Mark = 16mm
Static to Full Advance = 52mm
Left Full Advance to Right TDC = 112mm
#3: Right TDC to the Static Mark = 4mm
Static to Full Advance = 62mm
Left Full Advance to Right TDC = 114mm
The flywheel is 722.5mm circumference, 2mm = 1 degree Rotation.
You can also determine distance by ring gear teeth. Divide the number of teeth by 360 and you've got it. There are 96 teeth, which works out to 3.75 degrees per tooth.
Awesome, I'll try to do some digging and see if I can find what the G5 is suppose be. Thanks!
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These are some creative ways to remember the D&S :grin:. I did have those memorized, the problem I was having is there is no marking for the static mark and advanced mark so trying to figure out where they belong in regards to the D and S or TDC.
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To be pedantic and more correct, Italian nouns have 'gender' and their adjectives must agree with that gender. So, if we are talking about the 'right side' our adjective will change. 'Side' is a masculine gender noun 'lato'. The adjective becomes 'Destro' with an 'o' rather than 'a'. 'Lato Destro' = right side. The spark plug or 'candela' is a feminine gender noun. The right spark plug or 'candela destra' resides in the right side of the motor 'lato destro'.
Patrick Hayes
Fremont CA
Lol, moto is feminine... there are so many ways to explain the right and left using either gender (la sinistra della moto vs il lato sinistro della moto). i was just pointing out the origin of S and D.
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Awesome, I'll try to do some digging and see if I can find what the G5 is suppose be. Thanks!
My guess is the G5 fits category #3. Category 2 are the high performance bikes with higher compression and large carbs.
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Bring the right hand cylinder to TDC on the compression stroke (D) , then go back 8 teeth and mark the flywheel with a dab of white paint.
Do the same for the left hand side (S) and again go back 8 teeth and mark the flywheel with yellow paint ( the colours are for easy visibility )
That way when you use your timing light you'll be able to verify they are at least equal , from there you can fine tune your timing to what
works best for your bike (and riding habits) . This has been a favoured method to allow one to get started. Peter
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you could be one revolution (360 degrees) out. (same as the timing marks)
???
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Are you doing a tune-up? After getting it to operating temp. Pull clutch in and stab the start button. If it starts without cranking. Your timing is spot on. Don't screw with it.
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Are you doing a tune-up? After getting it to operating temp. Pull clutch in and stab the start button. If it starts without cranking. Your timing is spot on. Don't screw with it.
It does start right up once warm. I know it’s close but the problem is that the right side is getting hotter than the left. It also backfires once in awhile. It’s close but not quite there and It’ll drive me nuts until I get it right!
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Rotating the crank. If your looking through the timing hole, you would rotate the crank up. If your using the bolt on the alternator, you rotate clockwise.
Now if you want to look at it one more way. While sitting on the bike in riding position (which is normally how the right and left of a bike is decided), it rotates counter clockwise.
IF you don't want to go though the effort of making advance lines, again, get the timing light with the advance feature. Just make sure your TDC's are correct.
I also believe your bike should be #3. D should be 2 degrees BTDC and S should be 3 degrees BTDC. Full advance timing should be 33 degrees.
Make sure your valves are correct. .008 inch for both is the book IIRR. Pete Roper said to go .005 intake and .007 exhaust.
Tom
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Rotating the crank. If your looking through the timing hole, you would rotate the crank up. If your using the bolt on the alternator, you rotate clockwise.
Now if you want to look at it one more way. While sitting on the bike in riding position (which is normally how the right and left of a bike is decided), it rotates counter clockwise.
IF you don't want to go though the effort of making advance lines, again, get the timing light with the advance feature. Just make sure your TDC's are correct.
I also believe your bike should be #3. D should be 2 degrees BTDC and S should be 3 degrees BTDC. Full advance timing should be 33 degrees.
Make sure your valves are correct. .008 inch for both is the book IIRR. Pete Roper said to go .005 intake and .007 exhaust.
Tom
Tom that does make sense. If I verify TDC and use the light to time the advance do I not need to worry about the static timing? The valves I just set to the book spec earlier this spring.
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The 2 and 3 deg static can be set with the bike at idle with a light. Or you can use a multimeter hooked to the point and ground and watch for the point to open.
Tom
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It does start right up once warm. I know it’s close but the problem is that the right side is getting hotter than the left. It also backfires once in awhile. It’s close but not quite there and It’ll drive me nuts until I get it right!
Sounds like that RH carb is running lean. When was the last time you cleared the jets? Some of that real fine grit that is in the carbs (white stuff) could be starting to plug the main jet on that side carb. One thing you can do is check the air flow through the carb mouth with a 1/4 " fuel line while the bike is idling. (after reaching op. temp.) Don't stick the tube in your ear but place it to the outside of your ear.
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Sounds like that RH carb is running lean. When was the last time you cleared the jets? Some of that real fine grit that is in the carbs (white stuff) could be starting to plug the main jet on that side carb. One thing you can do is check the air flow through the carb mouth with a 1/4 " fuel line while the bike is idling. (after reaching op. temp.) Don't stick the tube in your ear but place it to the outside of your ear.
Just rejetted and cleaned the carbs. That’s a good idea with listening though. I’d think carbs as well but the fact that the left is fine (maybe slightly rich) makes me think timing.
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The 2 and 3 deg static can be set with the bike at idle with a light. Or you can use a multimeter hooked to the point and ground and watch for the point to open.
Tom
It has dyna ignition. But I did use a 12v light to set it. The problem was I didn’t have an exact point to set to. I just ball parked where it should be based on what I’ve seen online of the markings. That way I could at least get the bike on and go from there. I’m liking the idea of a timing light with the advance. I’ll be near harbor freight this weekend and pick one up.
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Consider that the fine tuning of your bike is of 2 separate single cylinder engines that need to be synchronized together. Definitely check your carbs for flow.
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Why not use a Piston Stop and Degree Wheel to find exact Compression TDC for one cylinder?
Then use the Shop Manual and the Degree Wheel to to determine and mark all the timing locations on the flywheel.
That way you have standard reference marks forever.
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You say you re-jetted. What did you re-jet to?? What carbs? What slide?
For everyone here...... Can a Dyna ignition system timing be off on one side? Sorry, I don't know Dyna.
Tom
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Why not use a Piston Stop and Degree Wheel to find exact Compression TDC for one cylinder?
Then use the Shop Manual and the Degree Wheel to to determine and mark all the timing locations on the flywheel.
That way you have standard reference marks forever.
I was thinking I will do this as well. Now is there a benefit to a piston stop vs placing a straw and visually seeing where TDC is? Maybe that’s a dumb question but I have seen both mentioned.
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You say you re-jetted. What did you re-jet to?? What carbs? What slide?
For everyone here...... Can a Dyna ignition system timing be off on one side? Sorry, I don't know Dyna.
Tom
Rejetted to 140 main and 55 pilot. Needle on second notch. It seems to have great throttle response, idle and cold start.
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I was thinking I will do this as well. Now is there a benefit to a piston stop vs placing a straw and visually seeing where TDC is? Maybe that’s a dumb question but I have seen both mentioned.
Piston Stop handled with proper care is more accurate than a straw.
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Now is there a benefit to a piston stop vs placing a straw and visually seeing where TDC is? Maybe that’s a dumb question but I have seen both mentioned.
No dumb questions. The straw is a coarse instrument. The piston stop is precise IF you know how to use it. The straw lets you sort of 'feel' where top dead center is located, plus or minus a few degrees.
Set up a degree wheel and the piston stop.
Gently roll the engine until the piston rises and hits the stop. It won't go any further. Mark that point on the degree wheel.
Now gently roll the engine in the opposite direction of rotation. The piston will drop to bottom and then rise again until it again hits the stop and goes no further. Mark that point on the degree wheel.
Look at your two marks on the degree wheel.
Top Dead Center is precisely midway between those two stop marks.
Patrick Hayes
Fremont CA
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....and I can't overstress "GENTLY" touch the stop in both directions. Then repeat to be sure you didn't knock some carbon loose mid procedure and get a false reading. If both checks match then you probably have a good reference.
Piston stop has a ball end and too aggressive rotation could dent the piston crown decreasing procedure accuracy.
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Thank you Patrick. I had been wondering about the piston stop. Also been wondering about TDC while using a straw. How many degrees can the crank rotate while the straw or a dial indicator will not move??
This does not matter that much for valve adjustments, but for timing at 2 degrees, it could be significant??
Tom
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I fabricated a piston stop set you can borrow (if I can find it). Hole through allows escape of compressed air.
(https://i.postimg.cc/vT4jS0mC/MVC-906X.jpg)
Patrick Hayes
Fremont CA
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If anyone is interested. At least on my Ambo 750 and probably all round fin engines, the TDC marks on the block are 25 ring gear teeth apart.
Tom
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Tom - 25 teeth apart doesn't sound right to me.
With 96 teeth on the ring gear, it should be 24 teeth between TDCs since it's a 90 degree V.
Is there something I'm missing?
Do all the tontis have 96 teeth ring gears?
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I put a ring gear on my Ambo flywheel. I lined up the arrow on the flywheel with the pointer on the block for #2 cylinder. A ring gear tooth lined up with the arrow and the pointer.
I counted the tooth that was lined up as #1, then counted the teeth until I got to the next pointer and called that tooth #25.
I guess that you could also say that there were 23 teeth BETWEEN the pointers.
AFAIK, an per MG Cycle, I had the standard ring gear that would fit my Ambo, Eldo and V1000 (not sure what bike, G5 maybe).
http://www.mgcycle.com/index.php?main_page=product_info&cPath=193&products_id=2460
Edit: I checked my ring gear and flywheel. There are 25 teeth as long as you include the ones at the marks like I stated. I also decided to put a TDC mark for #1 cylinder on my Ambo V1000. I also verified that a mark I put on the timing gear cover for #1 was correct. I made the mark while the engine was on my work bench.
I lined up #2 on TDC on my belt pulley, then turned it to the #1 TDC mark I made using the bolt on the nose of the crank. Then I put a mark on the flywheel, center of the timing hole on the bell housing. Then I turned the ring gear one tooth at a time with a screwdriver. I was expecting 25 teeth, I only made it 23 pulls of the screwdriver before it lined up. As I mentioned before, there are 23 teeth between the marks, I think that is why I only made 23 pulls.
Tom
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Thank you all for the information! I found a section in Guzziology that listed the G5 specs. TDC to Static is 4mm (~2deg), Static to full advance 62mm (~31deg), and S Full advance to D TDC is 114mm (~57deg). I'm going to go with these unless I hear differently. It has seemed a little confusing on the wording of which way to rotate the engine between different manuals, however my take away has been that the new marks belong above the D or S if you are looking into the window at the flywheel.
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Tom said "I counted the tooth that was lined up as #1, then counted the teeth until I got to the next pointer and called that tooth #25."
I think that's the difference. I wouldn't count the first one. It's like saying the starting line is one foot, when a foot long isn't till a foot later. LOL
We're talking about a unit of distance here. If there's a tooth at the starting line, that doesn't mean there's already a distance of one tooth. A tooth is 7.5mm - look at it that way.
I guess the way you did it can communicate - but make sure the other guy knows the parameters. It's not actually the distance of 25 teeth, it's in the way it's counted.
mneumann - yes, you've got it. The engine rotates clockwise looking at it from the front. The full advance and static marks are above the TDC mark.
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I should have posted a picture to show what I was trying to say. Sorry for the confusion :embarrassed:
Tom
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No dumb questions. The straw is a coarse instrument. The piston stop is precise IF you know how to use it. The straw lets you sort of 'feel' where top dead center is located, plus or minus a few degrees.
Set up a degree wheel and the piston stop.
Gently roll the engine until the piston rises and hits the stop. It won't go any further. Mark that point on the degree wheel.
Now gently roll the engine in the opposite direction of rotation. The piston will drop to bottom and then rise again until it again hits the stop and goes no further. Mark that point on the degree wheel.
Look at your two marks on the degree wheel.
Top Dead Center is precisely midway between those two stop marks.
Oh that's good stuff...so to be clear..
The piston stop doesn't need to be at TDC? You set the stop, close, but no need to exactly hit TDC. Or anywhere. Could be an inch before TDC. You roll backwards 180 degrees through a cycle, and boom! Split the difference is TDC?
I've got six, oops, now seven mopeds that need that....
Patrick Hayes
Fremont CA
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Chuck - the reason for using the piston stop is because the piston moves very little for quite a while at the top of the stroke. It's better if the piston-stop is close to TDC, but works as long as it's not inches away. Besides, the piston stop is only so long anyway.
I've never really needed a piston stop, but it's looking more and more like I'll be making one. I'll probably put a hard rubber insert on the end.
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In place of a piston stop, some guys with too much time on their hands have made a TDC gauge. Like this one for a Centauro:
(https://i.ibb.co/ftcTYTX/D8044258-DDAF-4-D00-8-D56-77-E48-C215-BBB.jpg) (https://ibb.co/ftcTYTX)
private image hosting (https://imgbb.com/)
Because of the “dwell” at TDC, though, you still need the degree wheel. You use the tool to find the dwell position, and set the dial to zero. Then you turn the motor in one direction to drop the piston, say .020, then turn the motor the other direction back through the dwell position to .020 again, noting both of the .020 measurements on the degree wheel. TDC is then read on the degree wheel half way between the two .020 measurements.
More accurate than a piston stop? Maybe. Make any difference on a street motor? I doubt it.
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I have a dial indicator setup. Is it more accurate than a piston stop and degree wheel? Not really. It is certainly easier, though, when you are dealing with cam timing.
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I get concerned that the indicator slide is being pushed from the diagonal rather than along its axis. This is not how those long travel indicators were meant to be actuated. That push direction is sliding the indicating shaft across the top of a debris covered piston. Indicator is fine if head is off and indicating rod is parallel to the bore resting on a single portion of the piston. Otherwise I would be suspect of TDC readings made at an angle through the plug hole.
Piston stop just touches one spot on the piston. It is the identical spot in either rotation.
Don't make the tip out of hard rubber. Use steel. Rubber will deform and impair accuracy. A spherical end handled with a reasonable amount of care will not damage your piston.
(https://i.ibb.co/tzzs0HV/1589067410126-1988398211.jpg) (https://ibb.co/tzzs0HV)
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That’s not the purpose of the indicator. Since the spark plug hole is offset and angled in relation to the piston’s direction of travel, an indicator screwed into the spark plug hole will not show the actual distance the piston travels — that is, if the indicator shows .020, that doesn’t mean the piston actually moved .020 down the bore. The purpose of the indicator is just to give comparative measurements for the degree wheel.
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That’s not the purpose of the indicator. Since the spark plug hole is offset and angled in relation to the piston’s direction of travel, an indicator screwed into the spark plug hole will not show the actual distance the piston travels — that is, if the indicator shows .020, that doesn’t mean the piston actually moved .020 down the bore. The purpose of the indicator is just to give comparative measurements for the degree wheel.
Never said purpose was to derive exact measurements. The object is to detect when piston travel reverses.
I'm just saying that it is poor technique to actuate a long travel indicator by applying a pressure load that is not parallel to the axis the indicating rod moves. Namely, push the rod straight in. That's how it was designed to work.