Odd Engine Seizure.... 82 xj650

Hello,
I hope you can help me get back on the road.
My beloved 1982 xj650 60xxxkm has decided to seize on me.
I rode it 10 minutes down the road and parked it, no issues.
When I went to fire it back up... Only the sound of the starter engaging, but not turning the engine.
I assumed it was a dead battery or faulty solenoid/starter, so I tried push starting it in all five gears, causing the rear wheel to skid every time I dropped the clutch.
If you have come across this before, or have some thoughtful advice... please let me know whats up.
Cheers

 

I think first thing to do is remove the engine timing cover and try to turn the engine over with a spanner with the engine in neutral.
IF there has been some kind of seizure this will rule out the pistons/crank etc. It should turn fairly easily, but there will be some resistance due to compression. As mentioned, take the plugs out as well.
If it rotates ok, put the bike on the centre stand, click into first gear, clutch in, and try to rotate the wheel by hand. You may need to give the wheel a good push/rock to overcome the clutch initially and help select first.
Bump starting any large bike can be a bit of an art if your on your own.

 

More likely you had fuel spill into the engine and hydro-lock a cylinder. If you force it any way you can bend a rod.

Pull the spark plugs, then try to turn it by hand. I bet you get a cup of gasoline out one of the plug holes.

 

Yup, pull your plugs before you spin the engine with the timing nut. If in fact this turns out to be a hydro lock situation, don't just clear the excess gas and think its cool to start riding it again, pull the carbs and clean them to free up the sticking float needle, then fix or replace your petcock. In other words, fix the cause, not the symptoms of this problem.

 

and don't forget to change the oil. if that is indeed the issue.

CN

 

Umm..... just remove the oil fill cap and take a whiff. If there is gas in the case you'll smell it; you'll also notice that there is no bubble at the top of the sight glass, indicating that the case is overfull.

 

tip the bike way to the right, and pull the left shifter cover. Look through the access hole and see if there's any pieces of the chain guide laying in there. It's a pretty good symptom of a broken chainguide piece jamming up the works. Many times you can work the piece out through that hole. tipping the bike way the to right like that allows you to do the job without dumping the oil all over.

Some of the sources that I use refer to this as the "Emergency Guidectomy" procedure.

But then again, it could be a number of things....we have to narrow it down.

Dave F