Bits in sump pan.

[SqDancerLynn1]

I stand corrected then,

[Froudster]

No problems with shifting CafeKid.

[TheCafeKid]

No problems with shifting CafeKid.

Then likely youve not had any of that stuff find its way into the tranny. As I said tho, I would get that dastardly thing out of there as soon as you can. Eventually, it will spill its guts completely, and then all that lovely metal will be floating around in your otherwise fantastic motor. Mine were actually getting enough force put against them that they were pushing out thru the backing plate of the starter clutch! Pretty crazy. Looked like someone had taken a cutting torch to it.

[Froudster]

What sort of mileage would be needed to wear the starter clutch to that extent, as this one has only done 25000?

[tfb]

What sort of mileage would be needed to wear the starter clutch to that extent, as this one has only done 25000?

No idea... but mine had over 100,000 kms when I got it. But for all I know that might have been the 3rd or 4th starter clutch!

Or, your machine might really be 125000kms... (which isn't a big deal, you can just rebuild the top ends on these things and then get another 1/2 lifetime's riding out of them!)

As with TheCafeKid, my old starter clutch had holes smacked right through the outer metal 'sleeve' of the clutch unit, presumably from the infamous 'kick back' that these starter clutches can produce.

What actually causes this kickback is a matter of debate, but personally I point the finger at the hub of the large gear which the clutch bearing engage with... it seems to be soft enough to get mild 'dents' in it from the 3 bearings, which then means the bearings can skip around it until they lock into a dent. Either way, not a good design, I'm afraid to say.

[Froudster]

A work collegue who has the same bike as mine (he's owned it for 28 years!!) is going to let me borrow the rotor locking tool and the puller tool to get it off, so I can investigate the starter clutch.
I'll let you know what I find

[Flying Fish]

What sort of mileage would be needed to wear the starter clutch to that extent, as this one has only done 25000?

The actual mileage might not be important, it's how many times the starter has been used. eg if the bike was used to commute to and from work which was only a mile away the starter has been used 25,000 times, if it's been used mostly for cruising 100 miles at a time then the starter has only been used 250 times.

[Froudster]

Very true Flying Fish

I have just had a look at the starter clutch from an 80's GSXR 750 and the set up is the same as the GS one. What concerns me is that the GSXR one is cast and riveted steel construction with the rollers and springs and the piece I have found in the sump is aluminium. I cannot believe that the GS would have used an aluminium construction....but I'll find out later in the week when I strip it down to investigate.

[hampshirehog]

The aluminium isn't from your starter clutch - that's all steel. A wild guess is that it's a bit from inside your stator cover but it could be from a few places other than that.

[tfb]

Yes, and that bit of aluminium looks like it's from some piece of engine casting that's suffered a whack on one side (small circular side) that has taken out a much larger diameter area on the other side...

I'm wondering if it's from an event unrelated to the starter clutch. [Perhaps the drive chain has broken at some stage in the past, knocked a hole in the crankcase, then the PO has repaired it without bothering to remove the fragment from inside the engine? That would be daft I know... but with some PO's all crimes are possible...]

Sorry, that's enough speculation! I should take up writing for the tabloids at this rate.

[76FJ55]

The large piece looks to me as though it is a piece of crank case where a blind hole was located and the PO put too long of bolt in it. then when tightened down it popped the back side of the case out. It appeas to be about a 10mm bolt that was threaded in there going by the diameter of the machined circular spot. Well, that is what ir looks like to me anyway. I don't know which spacific bolt that would be but if I come up with any ideas i'll post them.

[TheCafeKid]

Based on the BLACK colour of the backside of that large piece, the fact that there was some sort of bolt in it apparently, and the other items involved, i am still of the opinion it is part of the CAST STEEL (which has that rough black texture on the inside) rotor. Could be wrong, but bottom line is no matter what, you're not going to know untill you pull that stator cover off and have a looksee.

[Froudster]

The large piece looks to me as though it is a piece of crank case where a blind hole was located and the PO put too long of bolt in it. then when tightened down it popped the back side of the case out. It appeas to be about a 10mm bolt that was threaded in there going by the diameter of the machined circular spot. Well, that is what ir looks like to me anyway. I don't know which spacific bolt that would be but if I come up with any ideas i'll post them.

Alrighty then, just stripped the starter clutch out and it's as fresh as the day it was fitted. No sign of any wear at all
I'm gonna go with what you said above. Without stripping the entire motor we're never going to solve the mystery 100%. I suspect the bolt in question could have been the r/h side bottom sprocket cover bolt as the one I removed was far too long and the piece of aluminium pushed out would have dropped straight into the sump pan. The enclosed pic shows the mark left by the bolt when it was screwed in too far.

Thanks for all your help and suggestions.....And now I'm going to just ride the bike and enjoy the experience

[Jethro]

Haha, glad to see I'm not the only one to pull mystery meat out of the sump!

[tfb]

Definitely a starter clutch part in that lot, though. So what this now must mean... ... is that a PO went and fixed a stuffed starter clutch, but never cleaned out the debris.

So it looks like we're back to SqDancerLynn's original advice: just ride the bike! (aka 'don't worry, be happy').