[GSX750E] 1983 Clutch main nut loose upon inspection

[fededevi]

So since I owned the bike it always did a light whining intermittent noise 'in time' with the engine rpm. The sound peaks around 4500 rpm and it happens only under torque (under acceleration), in any gear.

Since I disassembled the bike to change leaking head gaskets and do a head 'check-up' I decided to investigate the problem. I inspected the clutch which, by the symptoms, was one of the suspects.
What I found when disassembling the clutch was bizarre, at least for me. The 'main nut' keeping the whole assembly together was very loose (basically free) but still locked in place by the bent washer locked on the splined shaft. The basket and gear assembly was also kinda loose on the bearing and wobbling a bit.

Is the slight "wobble" of the main gear normal and what can cause the nut to get so loose?


Sorry for my english.
Federico.

 

[Carter Turk]

Not sure if APE in California makes a hardened steel nut for this particular bike, but the stock nut threads have been known to stretch over time, even with the proper torque specs put on them.

Maybe the helical gear on the clutch basket, forces pressure outward straining the nut over time.

I've found many loose ones over the years of ownership, once the washer is bent flat.

Suppose the roller bearing inside the clutch basket could wear out, causing the clutch basket to rock a bit, though I think a very small amount of "movement" is normal.

 

[salty_monk]

Common problem. I think the 1150 Stock nut is also meant to be a harder material. It's also a different wrench / spanner size but the same thread.....

 

[fededevi]

That makes sense, the big helical gear puts an unbalanced axial load on the assembly and and over time unscrew/stretch the nut. I wonder why they used a helical gear here, noise reduction? The load shouldn't be that high.

I suppose cleaning degreasing and using thread lock on the nut/shaft will make no difference? I might try to machine a larger nut with some slight interference on the threads or with harder steel.

I'm also tempted to replace the main gear bearing but I wonder if it makes sense to change the roller without changing the bearing surfaces. Also I can't really measure any wear on pins and surfaces, nothing greater than 0.01mm at least.

 

[Grimly]

That makes sense, the big helical gear puts an unbalanced axial load on the assembly and and over time unscrew/stretch the nut. I wonder why they used a helical gear here, noise reduction? The load shouldn't be that high.

They realised that most riders would whine about the whine.

 

[Guest]

I found the same situation with my 1100e when I was trying to track down a noise that ended up being a broken bolt on the starter clutch. I just installed an APE clutch hub nut the other day, I also had a slight rocking movement to the basket but inspected everything to conclude it was a usual thing...not alot of movement mind you.

 

[Guest]

Here is the 1100/1150 nut. http://gszone.biz/clutches.html

 

[fededevi]

Thanks for the info to everybody, I'll eventually check the starter clutch too then.