Starter won't engage when Hot

Hello all, my XJ650J has problems starting when the engine is hot after riding for awhile. The starter cranks but it doesn't engage. If I let it cool down it starts fine the same as it does when it's Cold and when I first start the engine. Usually on a truck it's the
solinoid but the solinoid is not hot. I've pulled the starter apart and cleaned it up but it didn't make any difference. II would appreciate any information on what direction to pursue. Thanks

 

The starter clutch is slipping, or in need of rebuild.
What oil are you using?

 

I believe Lucas 10-30w motorcycle oil.

 

What do you recommend for oil

 

Is it an automotive oil or does it say motorcycle oil ?
10w40 is preferable and it should have a JASO MA rating for motorcycles
Some automobile oils have too many friction reducer additives for wet clutch engines.

 

Im currently at work so I'll have to check when I get home. Im pretty sure it says motorcycle on it. Thank you.

 

Hello this is the type of oil I've been using. Do you have any other ideas that might be causing my issue?

 

Unfortunately the only other possibility at this point is that the starter clutch needs to be rebuilt.
That operation requires splitting the engine, which is more tedious than difficult (the cases have to be split, but the top end can stay in place), and gives you the opportunity to replace the alternator chain guide before it fails (they fail due to age).


Park her facing downhill, and deal with it next winter.

 

That's what I was afraid of. About how long does that job usually take? I may have to do it anyway it's embarrassing when your in town and your bike just won't start. Where do recommend is the best place to get parts?

 

I'm sure some of the more knowledgeable members can give you a better answer, but is it worth it to try some conventional oil that is of a heavier weight? Like 20w50? It may get you through this years riding season and then you can tear it down to rebuild over the winter. I would also suggest making sure your starter is up to par, spinning the clutch fast enough to engage. I realize your issue is only when hot but heat also equals resistance for the starter. Just my 2 cents.

 

I can try running some heavier weight oil. This bike sat for about 10 years before I got a hold of it. What do you think about running an engine cleaner or ATF in it to flush it?

 

This bike sat for about 10 years before I got a hold of it. What do you think about running an engine cleaner or ATF in it and flushing it out. Then trying a different oil.

 

You could dose it with Seafoam. That's one of the things we recommend doing if a low-friction oil has ever been used, before changing back to a JASO compliant oil.
That shouldn't be necessary in your case since you are using a JASO complaint oil (but maybe the PO wasn't, in which case that may be where the problem lies).
Another thing you can try is to remove the starter and spray carb cleaner onto the starter clutch to flush it out directly. Do that right before changing the oil.

Engine removal, case split, repair, and re-installation takes most of a long weekend. Budget two weekends so you don't try to rush things.
If you replace the alternator chain guide (and I think you should) be very careful when removing the bolts that hold the guide in place. They are held in with Yamabond, so a little heat will be needed or the bolts may snap off.

@chacal carries all the parts that you need, and won't sell you anything that doesn't fit.

 

Thank you

 

My seca 750 slips sometimes when hot , bought a spare engine , either going to tear it down , or swap it in and tear my engine down .

 

Sounds like a fun project

 

Having a similar problem. bought an 81 xj650 yesterday PO said the PPO probably used car oil causing the clutch to slip so today after work i changed oil/filter and now the starter only engages for a second HELP PLEASE?

 

See the reply in the other thread that you posted in.