XJ900F - Starter Clutch shot - Repair or break ?????

I have a XJ900F - 1989 model, which has done 31,000mls. The starter clutch (SC) has given up the ghost, and I have finally had to strip the engine down, splitting the crank cases to get to it.

On getting the SC out and on to the bench, I have now stripped it down to it's basic parts, only to find a scene from bike hell itself:

1 - The starter clutch gear is totally knackered, not only where the plungers grap the hub of this gear, it feels and looks like it's covered in nothing but ridges and undulations - should be smooth, but also the gear itself is copper in colour on the driving edge, no hardened metal left - great, this is scrap then, and will mean if I can replace, I'll have to change the idler gear and starter gear also! :cry:

2 - With the gear removed the thin plate that covers the rollers can be seen properly, and here I find a crack along the top and side - just great :cry:

3 - Remove the 3 scews and you get access to the springs, plungers and rollers, and can see the main part of the clutch that these rollers butt up too - Here I find 3 knackered rollers, and to make things worse, where the rollers push upto the metal body and are held in place to grip the starter clutch gear, this is cracked right through in 2 places - total scrap, just bloody great. :x

4 - On removing the circlip to remove the drive sprocket and check the cush drive and housing, the drive sprocket is very blue inside, and the teeth on the gear are also very blue and lacking the shiny hardened metal in many places - more scrap - it just get's worse - where's that rope :cry:

5 - On removing the cush drive, I find 3 bigs pieces of metal underneath and imbedded in the rubbers - are these the evil buggers that have turned my beautiful bke and engine to scap??? :evil:

The dilemma I am now in, is do I now scrap the bike and flog off all the good parts, genuine yamaha YICS tool and shim tool, or is it going to be possible to get the bits I need to replace all this nightmare :?:

I live in the UK, and I know this website is worldwide, so any advice any or all of you can give me on which way is best to go will be very appreciated.

 

Clean out all the crap & fit a new starter clutch complete, unless the gears have teeth missing they should be ok to re-use. Get the SC from Chacal (xj4ever) top right of the home page. If the mill had good compression & is not spewing oil, it should be worth the $$$$$$.

 

+1 to Wizard suggestion

Unusual problem....not come across it before...any thoughts on the cause? Weak battery?

 

+2 on the replacement.

You already have it apart, and parts are available to fix it.

Adrian. It is not all that unusual. It usually happens when the engine briefly fires the bike off, but does not get it to full running. That sudden surge on the chain sends a shock through the starter clutch causing it to eventually crack. The rest is the end result that the OP has to deal with.

A quick check on the parts shows that the 900 uses the standard 650 Starter clutch assembly with the exception of the outer assembly. The part that holds the rollers, and springs.

Ghost

 

Hi Guys

Thanks for all your input. Your explanation Ghost at least explains the probable cause of this mayhem.

Some of the parts don't seem available on the USA site, the gears and the main body part of the SC? I'll send Chacal a PM and ask him for some advice of availability of these parts.

The cost of doing this engine by the looks of this site is going to be quite expensive, and I really wonder if I would be able to recuperate the amount spent, especially if you include doing a proper rebuild now I've stripped the engine down to bits.

Let's see what Chacal has to say.

Cheers guys