Help needed........

Hi,i have stumbled accross this great site while looking for some info regarding an 1980 XJ650 that a mate and i am restoring.Its good to know there are other folk out there that have an interest in these bikes.


I am hoping that someone may be able to help me.
We have split the cases as the starter clutch appears to not be engaging.As we removed the bottom half of the crankcase,a small,single ball bearing fell from somewhere,and despite much looking and scratching of ones head,we cannot find where it came from.

Can anyone give me any idea as to where it may have come from??

Thanks

 

The starter clutch. It uses three such balls in a "sprag" arrangement; it quit engaging because the housing is cracked at the ball races. When you take it apart you'll find (hopefully) the other two balls and the broken housing.

 

Thanks for your reply Bigfitz.

We seperated the starter clutch assembly and it was all intact.
I was expecting to find the housing cracked but it wasnt.

The ball bearing we found was about 1/4 inch in size and having thought about it for most of today,i still have no idea as to where it goes.

Is there any part of the clutch assy that has a single ball????

Thanks

 

The oil pressure relief valve perhaps?


grz Thijs

 

The only thing that jumps to mind that would use a ball that big is the shaft bearings for the tranny and output shafts. The starter clutch uses rollers, not balls so that is eliminated as a potential. There just isn't anywhere else in the engine that a ball bearing could be sourced from. Is it possible that some twit dropped one into an unguarded oil filler cap at some point? Do you know the history of this machine?

 

Thanks Thijs and Robert,

We know very little about this bikes history.My mate picked it up cheap as a winter project.When we hooked a battery up to it the starter motor would attempt to turn the engine over for a split second before spining freely.
Suspecting the starter clutch to be dodgey,we split the cases to have a look.
The cases had been apart before and there was some damage to the lower engine case where the timing chain tensioner locates.

Possibility that the timing chain has let go previously which explains the cases having been split and the damage.

If there is nowhere in these engines that has a single ball bearing,then i guess it has either been dropped in there,as you suggested Robert or there has been a major bearing failure in this bikes history,and its a stray ball that wasnt rounded up during the repair.
Would love to know either way.

 

It looks about the right size though. Since the cases are split anyway, you could check the bolt which holds the oilfilter (and housing) to the block, since the ball should be located in there.


grz Thijs

 

Good show Thijs! I didn't think of that unit. On my filter bolts, the assembly is spiked into place to eliminate it possibly working free and migrating but anything is possible...
Dave1965, time to start counting bearing balls...

 

Another thing just crossed my mind... It could be a plug which belongs in the crankshaft. (on both outsides) For manufacturing purposes they need to drill the crankshaft to supply the big-ends with oil. After boring they often use a ball from a ball bearing to plug up the hole.

I don't know if the engine has run since you have it, but I guess if it was a plug from the crankshaft, you definately should have lost too much oil pressure and should have heard the big-ends knock.

A nephew of mine once had a 3,3 l diesel engine with oil pressure problems, it appeared then that one of those balls had come out.


grz Thijs

 

Thanks Thijs,you may have just solved my problem.
I will be going over to my mates house at the end of the week and will be heading straight for that oil filter bolt.

I will let you know how we get on.

Thanks again

 

Already found something?


grz Thijs

 

Sorry it has taken until now to let you know what we found,but you were "on the money" Thijs. Dank je wel


The loose ball bearing belongs to the oil pressure bypass/ relief.



Just wanted to thank you all for your help and info.

We have a fair bit of work to do to get this motor back into shape,but look forward to getting it back together.

 

You're welcome . (graag gedaan )

Keep us updated with the progress, always nice to see progressing projects!


grz Thijs

 

That would also mean that you have a loose, steel, Split-Pin and the Spring to look for.

I imagine a small piece like that pins size would be close to the Oil Drain Magnet.
I've never heard of this happening before.