Noticed the primary has a bad bearing sound when coasting / slowing in low gears. Also same noise in low gears while maintaining speed. Sound goes away with clutch (lever) released (engaged). Cruises in 5th gear very quietly. Accelerates and shifts through the gears without the noise.

Again, it's only when maintaining speed in 2nd, 3rd, or 4th gear, or coasting / slowing down does this rattley, irregular whirring sound appear.

I did tear into the primary and installed a new stator / rotor (followed all instructions). The noise wasn't there until this spring, about 5k miles since having taken it apart.

I just rechecked the primary chain tension and it's set perfect.

I don't think it's the compensator type issue, but maybe?

I'm leaning towards it being the clutch hub /pilot bearing. Anything else I should be looking for?

 

5th gear is straight through the tranny, could be a bad bearing or gear in the tranny. Drain the tranny fluid and check it with a magnet. We also had a loose clutch act like that once.

 

Since it's only in some gears and not others, you would think that it would be transmission related. Unfortunately, the primary case is like a big megaphone. Any noise from the transmission or primary usually sounds like it's coming from the primary because of this.

The two bearings that will make the most noise are either the bearing inside the clutch pack or the main shaft bearing of the transmission. Does the noise follow the speed of the engine or the back wheel? Clutch bearing noise will change when you shift gears since it's running at the speed of the engine/primary. Transmission main shaft bearing noise is constant with the speed of the bike and doesn't matter what gear you are in.

If it varies by gear and it's not either of these then it could be the small needle bearings inside the tranny. Finally, there's a bearing on the inner primary cover. Did you replace this bearing and seal when you had the primary off? The manual calls for replacing at least the seal any time the primary is pulled.

 

I never pulled the clutch pack but it looks like that may be the next concern. Certain years of EVO you are able to take the compensator off completely without aving to pull the clutchpack and chain.

Noise does follow the transmission activity. When freewheeling (coasting) it makes a lot of noise. Under load of acceleration I'm not hearing it. When downshifting as I come to a stop the noise follows the speeds of the transmission gears. Shifting to nuetral and coasting no noise.

I'm going to triple check the primary chain. It sounds like slop in the chain to me. The primary adjustment can be misread. I guess there is a point where the slack is adjusted by the tensioner and it equals out the top and bottom chain slack so there's no sloppiness to the chain. From what I understand you can misread the tension (play) if the bike is in gear at the time. You need to have the transmission in neutral and measure all the excess chain play out. I guess when attempting this in gear you can have play in the lower portion of the chain but not read it by just measuring the top chain freeplay. In other words with the transmission in neutral you can check the upper portion of the chain and not have some slack in the lower portion of the chain giving you a mis-read on the actual tension.

At least it's simple to go back in and re-check the chain.

So can anyone tell me what noise you hear in the primary when the chain is loose?

 

A loose primary chain doesn't make much noise at all unless it is so loose that the chain is slapping the side of the primary. You get whining from too tight a chain. Too lose just causes a lot of sloppiness when applying and releasing torque between the motor and the tranny and the associated noise of the chain tightening up. It doesn't make worn bearing sounding noises.

From your description, I would guess that it's time to change the clutch bearing. That bearing is pressed in. Pull the entire clutch pack and you can inspect the bearing. If it's making noises, you should have no problem feeling the slop and roughness while turning the bearing by hand. At the same time, you might want to look at replacing the clutch plates if they're getting worn or upgrading to a new, stronger clutch if you're in the market.

 

Thanks for the responses.

I've done a lot of reading today and think it's the clutch hub bearing. Now I need to tear into it and see.

 

I had a moment to go out to the garage and check what I could hear while sitting in the drive, I had been going down the road all the other times.

Clutch lever engaged / Clutch released: a clattering, churning noise begins and a slight "out of balance" feel in the bike, along with a scrapping / grating sound.

Clutch lever released / Clutch engaged: slightly noisy, noise stops when putting transmission in gear.

The scrapping sounds to me like the primary chain is dragging and contacting the case.

The wobbly, or out of balance feel makes me think a bad clutch hub bearing / loose compensator that would allow them to shift and wobble when disengaged and in neutral.

The scrapping grating sounds are probably the primary chain as it loosens and scrapes along the case from the wobbling hub / compensator.

It's odd how when under load accelerating the chain slack noises seem to go away, and when coasting in gear it's noisy.

Can't wait to open it up. Have to fit it into my schedule.

 

Well I had a chance to tear into it today.

With the primary cover off I can see there is no issue with the chain, and the noise is in the clutch.

It's a bit noisy when engaged, but when you disengage the clutch there is an unusually excessive rattling noise.

I'm on my way to get my dad's impact driver to pull the compensator and clutch pack and check it closer. *** UNLESS someone can tell me what else my issue is and I don't have to strip the primary down.

I don't see anything oscillating, or wobbling in an odd fashion inside, like the clutch pack. But it's kept in place somewhat with the chain still on it.

More later ... I'll check back soon to see if anyone has any more helpful ideas.

 

I'm still betting on the main clutch bearing.

 

Yep sounds like the clutch basket bearing is going bad. However it could also be the mainshaft tranny bearing. I hope it's the clutch basket bearing.