noise in gear box

[nighthawkes]

hey guys hawksy here , havnt posted anything in a while but I have a serious question regarding my 88 max, when the bike is in gear /anygear moving I get a whiring (bearing) noise on deceleration sound like straight cut gears . noise goes away when I disengage the gear box (pull clutch in) . hoping it would be the clutch throw out bearing ?(does it have one?)
sorry if this is a stupid question but am now getting concerned with the noise ( not getting worse,but still there)

bike has 38k on it .

cheers guys look forward to your replys

hawksy

 

[gleno]

Hey guys, I know this an old listing but no-one had a reply for it.

I have and '88 with 109,000ks on it and its just started making a similar noise in 4th and 5th gears. sounds like a bearing has gone bad and seem to be coming form the left side of the motor.

Most noticeable when I just gently roll on the throttle from coasting.

Any clues where I should start looking?

 

[NHVmaxpower]

lol I am having EXACT same issue tore down rear dif cked out ok . Now I will ck front bearings :-(

 

[gleno]

I found out what my noise was. I snapped the driven middle gear shaft at the yoke retaining bolt.

This left the yoke and the driven gear free to move and chewed out the driven gear teeth.

That pile of sharp metal is what a got out of the lower case.

All fixed now and no other engine damage.

 

[Rusty McNeil]

I found out what my noise was. I snapped the driven middle gear shaft at the yoke retaining bolt.

This left the yoke free to move and chewed out the driven gear teeth.

That pile of sharp metal is what a got out of the lower case.

All fixed now and no other engine damage.

Wow,

You didn't need to replace the middle drive gear too?

Would thought they would have chewed on each other....

 

[gleno]

You have to replace them as a set, so yes they both got done.

This is not a job for a novice as the clearances need to be very precise. (I got a very good bike mech to do mine).

The drive gear did not break any teeth (must be harder material?) but it does have obvious wear and micro-fractures in some of the teeth.

BTW: I reported this problem at 109,000kms. I fixed it at 116,000ms. The yoke and shaft were floating the whole time!!!!

 

[Rusty McNeil]

I buddy of mines PCW 1500 had the drive gear teeth fail, slightly damaging the driven gear.

We had to split the cases and replace both. Yes, it was a pain in the ass.

Turned out the "wafer spring/washer" (I do not know what it's really called) that puts pressure on the drive gear and pushes all the drive gear & tranny shaft thrust to right side of the case was not in the notch where it was supposed to be when PCW built the engine. This is easy to miss when assembling the case halves if not really on top of things.

You could tell by the wear pattern from where it had been flopping around on the driven gear shaft. This let the gear lash just be whatever it wanted to be.

PCW honored their work though, in parts at least.

 

[wildweasel_pt]

I repaired one once with the same issue, fortunately the shaft didn't creep inwards like yours chewing itself, i just replaced the output shaft and checked lash with original shims. worked ok. What keeps it from creeping inside is the ujoint sitting against the outer tapered bearing as soon as you shear the shaft tip it will allow it to creep inwards as the nut won't be there to keep it in place. These issues are more prone to happen if braking with the engine/gearbox by lowering gears very abruptly creating shuddering in the drive train, can happen either at front like yours or at the rear on the final drive pinion where the splined sleeve is bolted to.