[Mr_Gently]

Had only been riding a few minutes, maybe 2 miles from the house when she lost power very suddenly and seized up.  Pulled in the clutch and coasted to a parking lot.  Put her back in neutral and you can stand on the kickstarter with not the slightest budge.   Other than bottom end bearing failure or top end seizure, is there anything else that can cause this?   She's got plenty of oil in her and it's clean. Hadn't ridden her far enough for her to even get particularly hot.   

[cyrusb]

Year? Mileage?

[Mr_Gently]

2001 Military, 4300 miles.... all stock except for right foot shift conversion. I'm the second owner. 

[cyrusb]

If you put it in last gear and rock it is there any movement? If you have electric start the sprage has been known to chock the primary with broken pieces, rocking it may disloge them. Having said that, piston seizures are not that uncommon.

[Mr_Gently]

It is an electric start bike.  I I put it in 4th gear and rocked it back and forth a few times. Put it back in neutral and the kickstarter is still froze. 

[neil]

Hi Mr. Gently:

Electric start means your  bike is equipped with sprag gears. Do you use the electric start or do you kick start it? If you use the E. start has it been making a loud bang from time to time when you press the start button? Just checking if the sprag could be the root of your problem. My sprags failed several times and at least twice they hung up in the primary and locked up the bike. No E.start or kick start would free up things until the primary was opened and the offending broken gear parts were removed. Were you down shifting or up shifting when this happened? I had sprag failures while I was riding and down shifting.

Dealing with sprag failure is a bit more easy than rebuilding the motor. Thought you might want to check out the simple stuff before getting to the more serious possibilities.

Neil

[Mr_Gently]

It all happened so fast that I couldn't even tell you if I was shifting or not when it happened.  I had just made a left turn at a traffic light and was probably either in second gear accelerating or maybe shifting into third. I wish i could remember.  There was a noise when it happened and I grabbed the clutch, so it's possible that I already had the clutch pulled in to do the shifting when it happened.         

I've heard a lot of moaning and crying and teeth-gnashing over the sprag clutch issues..  I had been considering trying to swap out for a kick only bike recently as a result of those complaints. Or, upgrading to one of the new EFI bikes.

[The Garbone]

I think you might just need to pull apart the primary case and try to isolate the seizure to either the engine or sprag.   No matter how you cut it you have some work ahead of you.

[Mr_Gently]

My gut is telling me that it's the sprag, but I haven't pulled the primary cover yet. The bike wasn't hot, and it was full of clean oil and was not being ridden hard or fast or lugged or anything of that nature.  Just a quiet little 2 mile ride to Wendy's to get a salad for lunch. 

Maybe tomorrow afternoon I'll pull the primary cover and see what sort of carnage lies therein.  On the bright side, that seems like less trouble/money than a screwed up crankshaft.  If it turns out to be the top end, which just doesn't seem that likely, I'll probably go with a new alloy barrel,  If I don't pass it on to the next rider to worry about.

[Jinx]

Could have dropped a valve? Or valve seat. That locked mine up.   No bad damage but required new valves and seats.
 Hope it's minor no matter what.

[Rosetap]

Also very likely the oil pump spindle could be stripped, making it an engine seizure.

[Mr_Gently]

Pulled the primary cover off today and found a couple of loose nuts that had come off of the mounting studs for the alternator lying in the bottom of the primary case.  The oil residue remaining in the case after I removed the cover seemed to have some very fine grey residue in it.  Don't know if that means anything or not.           Haven't removed the alternator or the primary chain or clutch.  Everything except for the couple of loose nuts seemed normal.         In the event of a sprag failure, one would expect to see all sorts of bits and pieces in the primary case, correct?           Is it possible for a nut or some other crap in the primary compartment to get caught in the chain and make the engine unable to turn over?   Seems unlikely as the momentum of the engine would probably just chew up anything that got caught in the chain, or if it was big enough, destroy the chain itself.         I also put the bike in gear and rocked it back and forth a bunch of times to see if anything would get jarred loose, but when returning it to neutral the engine was still completely immobile.     

[n1acguy]

Unless there's a nut or broken piece of sprag jammed in the electric start gears behind the alternator, I'm afraid it sounds like your engine seized.
The grey residue is just some wear of the clutch and other components, and of itself, is normal.
I'll cross my fingers for you and hope there's something jammed in the gears.

[barenekd]

Pull the alternator off and see if the rotor has been rubbing it. You should be able to release the clutch and if the wheel moves, it's most likely the engine Then remove the primary chain to separate the engine from the gearbox and see which one still turns. . Anyway, grab ahold of the rotor and see if you can rotate it or feel any up and down movement. If it won't rotate it's pretty obvious what's stuck. If you get much up and down movement the main bearing is gone. Either case, you're in for a teardown.

Bare

[The Garbone]

Take everything out of the primary, clutch and all.  

You will have to remove the clutch assembly and plates as well as the big bolt in the center of the basket.  It might take some work to get the primary chain / clutch basket off.

Once everything is out you should be able to spin the starter gear with your hand or a screwdriver.  If it it does not move that is you problem.  You should also be ably to move the transmission and rear tire with the kicker.

I would remove the spag/ starter stuff anyway if at this point and put it all back together.  

If the seizure appears to be in the engine when all is said and done pull the head and check for a dropped valve.   The last thing to check would be pulling the timing cover,  but if you get that far it could be very bad...

[baird4444]

you say a couple of nuts from the alternator...
      is it possible the stator coils have jammed against the center?
      Try removing the existing nut and swing the coil up and rest it on the
      case....    are you still locked up? 
     it may not be this simple but never over look the obvious...
                - Mike

[drewmann]

Hi ,mine did same thing and was key in rotor shaft had sheared off and locked up on stator ,nut holding rotor on had snaped off as well ...good luck !

[neil]

Hi Mr. Gently:

If you have failed sprag gears, you won't be able to see them until you remove the inner primary case and remove the small metal pocket on the rear that holds them. You may have to gently turn the partially exposed drive gear in order to pull the engine sprocket prior to removing the inner primary cover. Then you will be able to tell if it's sprag gears or engine failure.  My sprags failed the way you are describing. Everything locked up and I had to tear down the primary before I could make the determination. When I was satisfied the sprags had failed again, I went for the kick only solution.

Neil

ps. If you go kick only, dump the lumb on the inner primary and get the correct inner primary. It'll make your life much easier for down pipe and muffler changes.