Bad Vibrations

[JEEPRUSTY]

Just thumpers, V twins and other designs with poor primary and secondary balance. Some of them even have balance shafts and still need bar end weights. Inline fours generally don't need them. Should be about as smooth as a car engine.

I took mine out and they are pretty darned heavy never ran the engine without them I Imagine they do a lot.

[raistian77]

I have put 4,186 miles on it since june 11

[raistian77]

Shim and bucket gurus isnt that an extreme amount of clearance loss in 2000 miles?

Is it possible that your timing chain jupmed not sure if this is possible without breaking the engine.

Also maybe you are not checking your clearance properly.
There is a video of a gs 500 being done on youtube but I dont know if the process is the same.

The service manual states to check with cam lobe straight up, prefered or intake straight back and exhaust straight forward. I did mine all straight up.
clearences are 0.001-.003 inch
1 I-.001
1 E-.0015
2-I-.0025
2-E-.005
3-I-.001
3-E-.00125
4-I-.009
4-E-.003

I have a metric set of feeler guages but they jump between ranges to much
my SAE guages are machinist guages they advance in .00025 measurements starting at .001

As you can see 1 and 3 are on the cusp of being to tight
2 exhaust is to loose as is 4 intake
4 exhaust is fine

[tkent02]

Use the Suzuki service manual method of lining up the cams, you get much more accurate readings. Looser is better than tighter, especially after having been too tight.

[raistian77]

Use the Suzuki service manual method of lining up the cams, you get much more accurate readings. Looser is better than tighter, especially after having been too tight.

That is the Suzuki method in the service manual

Straight up or to the rear for intake
Straight up or to the front for the exhaust

[tkent02]

Not quite, one of the pair up, the other forward. Measure them both at this position. So for instance, measure #3 and #4 exhaust at the same time, one lobe up, the other forward....
Maybe that's what you meant?

[raistian77]

Not quite, one of the pair up, the other forward. Measure them both at this position. So for instance, measure #3 and #4 exhaust at the same time, one lobe up, the other forward....
Maybe that's what you meant?

I usally check twice, once lobes up than pointed staight. But, in reality it should make no difference, when I ran a auto shop we had many cams ground to spec for us for blueprinted engines. Once you are off of the lift part of the lobe, the distance between the lobe and cam should be equall all the way around till you ramp up for the lift again.

[tkent02]

I usally check twice, once lobes up than pointed staight. But, in reality it should make no difference, when I ran a auto shop we had many cams ground to spec for us for blueprinted engines. Once you are off of the lift part of the lobe, the distance between the lobe and cam should be equall all the way around till you ramp up for the lift again.

The thing is the cam gets pushed out of line when one of the pair is pushing a valve down. Remember, unlike a car there are only two bearings on each cam. But it really doesn't matter, a slight error either way is not the source of your vibration problem.

[raistian77]

The thing is the cam gets pushed out of line when one of the pair is pushing a valve down. Remember, unlike a car there are only two bearings on each cam. But it really doesn't matter, a slight error either way is not the source of your vibration problem.

Good point, this is kinda fun learing the diffrences between auto work and bike work. But you are right that would not cause the vibration. However what do you think is causing the fast clearance changes?

[tkent02]

However what do you think is causing the fast clearance changes?

The fact that it was too tight. If you look through the spark plug hole while the valve is open, a good valve will have a silver circle where the valve contacts the seat. If you look at one that has been run too tight, there is no silver ring, it hasn't really been contacting the seat. You adjust the clearance, now it can close. But the sealing surface is a little messed up, not sealing as nice as it should. Maybe it's even burnt just a tiny bit. After the valve closes a few million times, that seal starts to get better, forms the silver ring again, the valve sinks into the seat a tiny bit further, the compression gets better. As it does, the clearance gets tight again. Not sure if my reasoning is correct, but they usually do improve, and they usually need a few valve adjustments along the way. I have seen this happen on four GSes this summer, probably will see the improvement on a few more once I get them on the road. Valves were too tight, adjusted them, the compression came up. They almost always get better with miles, and need a few adjustments along the way. Had a guy here today, shop told him it needed a rebuild, due to bad compression. Adjusted the valves, got 115, 115, 116, 115.
(Low numbers due to the elevation here, at sea level they would all be in the 130s)


Of course, if the valve has been burnt too much, it will never improve, but if that was that bad it wouldn't have come up to 100 psi right after the first adjustment.

[raistian77]

The fact that it was too tight. If you look through the spark plug hole while the valve is open, a good valve will have a silver circle where the valve contacts the seat. If you look at one that has been run too tight, there is no silver ring, it hasn't really been contacting the seat. You adjust the clearance, now it can close. But the sealing surface is a little messed up, not sealing as nice as it should. Maybe it's even burnt just a tiny bit. After the valve closes a few million times, that seal starts to get better, forms the silver ring again, the valve sinks into the seat a tiny bit further, the compression gets better. As it does, the clearance gets tight again. Not sure if my reasoning is correct, but they usually do improve, and they usually need a few valve adjustments along the way. I have seen this happen on four GSes this summer, probably will see the improvement on a few more once I get them on the road. Valves were too tight, adjusted them, the compression came up. They almost always get better with miles, and need a few adjustments along the way. Had a guy here today, shop told him it needed a rebuild, due to bad compression. Adjusted the valves, got 115, 115, 116, 115.
(Low numbers due to the elevation here, at sea level they would all be in the 130s)


Of course, if the valve has been burnt too much, it will never improve, but if that was that bad it wouldn't have come up to 100 psi right after the first adjustment.

ok, so my next step will be to mail off the shims I have to the club and get what I need to make all the adjustments to the loose side and put some more miles on it and see what happens.

Also oil added to the cylinders does nothing to the compression numbers.

[tkent02]

ok, so my next step will be to mail off the shims I have to the club and get what I need to make all the adjustments to the loose side and put some more miles on it and see what happens.

Also oil added to the cylinders does nothing to the compression numbers.

Great, your rings are fine.

[Steve]

Dang, I should have asked Steve to test run it when he was here

I can stop on my way home, but that won't be until mid-November.

The service manual states to check with cam lobe straight up, prefered or intake straight back and exhaust straight forward. I did mine all straight up.

That is the Suzuki method in the service manual

Straight up or to the rear for intake
Straight up or to the front for the exhaust

Not quite, one of the pair up, the other forward. Measure them both at this position. So for instance, measure #3 and #4 exhaust at the same time, one lobe up, the other forward....
Maybe that's what you meant?

I usally check twice, once lobes up than pointed staight.

As tkent mentioned, you set the cam lobes on one side so that both lobes are at about 45 degree angles to the valve. On the exhaust side, that would be one lobe forward, the other one up. Without moving the cam, measure BOTH valves. Because neither lobe is pushing on a valve, the cam is centered in its bearing, so you can get accurate, repeatable readings. I did not ask you about details on your adjustment process, I just assumed it was done correctly.

I usually start with exhaust 1&2. Check both of them, rotate the crank 180 degrees, check exhaust 3&4. Rotate another 180, check intake 1&2. Rotate another 180, finish up with intake 3&4. Actual starting point does not really matter, but the progression will be the same.

.

[raistian77]

I can stop on my way home, but that won't be until mid-November.







As tkent mentioned, you set the cam lobes on one side so that both lobes are at about 45 degree angles to the valve. On the exhaust side, that would be one lobe forward, the other one up. Without moving the cam, measure BOTH valves. Because neither lobe is pushing on a valve, the cam is centered in its bearing, so you can get accurate, repeatable readings. I did not ask you about details on your adjustment process, I just assumed it was done correctly.

I usually start with exhaust 1&2. Check both of them, rotate the crank 180 degrees, check exhaust 3&4. Rotate another 180, check intake 1&2. Rotate another 180, finish up with intake 3&4. Actual starting point does not really matter, but the progression will be the same.

.

I will recheck once I get some shims in, I don't think it will be to much diffrent than the reading I got today. In a car there is no point where the cam is not pressing down on a valve, but there are more than 2 caps on em also lol