So I was out riding yesterday suddenly the engine died and rear wheel locked up.  Try to kick start it, wouldn't budge.  I was in 3rd and using about 1/4 throttle, and about 17 miles into the ride.

I have not ridden the bike hard at all.   I've put less than 4 hours/40 miles on this bike since I bought it used a couple weeks ago.  I had just finished tweaking the damping and preload settings too.   

What could have caused this?
*Radiator was full of coolant, looked very clean.  Reservoir was halfway between low and full.
*Oil was halfway between the hash marks

Might have broke a piston, a ring, dropped a valve, broke a cam chain etc etc. Very possible it hasn't been rebuilt in a long time if you just bought it.

It's hard to say what exactly it was that caused it, the guy above me gave a good example of what may have caused it, but you never really know until you start tearing it down... Let the fun begin!

Yes, let the fun begin.  I'm gonna start tearing it down tonight.

Do these engines just seize up over time if they are not rebuilt?

EDIT:  Also, probably about 12 miles into the ride, it started cutting out a little bit down hill, didn't think much of it at the time, figured I'd look into it when i got home. Guess that was a red flag

Edited by jamesm113, 23 April 2012 - 02:02 PM.

James,  Well, they can depending on the type of failure.  I bought an 03 YZ several years ago, and just rode it until it blew.  I put over 125 hours on it, just changing oil and filter.  The small cam gear wore out and allowed it to jump time.  I was lucky it didn't take the head out.  Did the valves and seats, chain sliders, chain, new crank- cams ok, and changed the piston, pin, rings, and keepers.  We ran a hone around 8 turns slowly to cross hatch it.  Spec was perfect,... in the middle.  That was 60 hours ago, so I'm about to freshen it up again.  The book says every 50 hours to do a piston and rings.  What I found was the piston pin was loose in the piston and on the small end of the rod.  So it was knocking at idle pretty good.  That's a sure sign.  Good luck.... they really are not that hard to do.

So, it looks like the kick starter is stuck... I'm able to turn the engine by hand via the crankshaft and was able to turn it over a few times that way, but the kick starter won't budge.

After that, I drained the oil, it looks like there are some tiny metal shavings.

The timing might be off a little though.  I lined up the I on the crank, and the outside dots on the cam sprockets are pretty close, but the other dots don't make much sense to me.

Timing mark pictures:
http://i1028.photobu...ng/DSCN5454.jpg
http://i1028.photobu...ng/DSCN5449.jpg
http://i1028.photobu...ng/DSCN5450.jpg
http://i1028.photobu...ng/DSCN5452.jpg

Yes your timing is off....all those lower dots should be in line/parallel with the surface of the head.
looks like your off a tooth or two.
time the exhaust cam first, taking up the slack on the chain then match up the intake cam to it.

IMO you need tO keep looking. Engines don't lock up because kickstarter is stuck. Kickstarters usually stick because the engine seized or the tranny broke or the clutch broke.

jzheesh people have bad memories! In 2001 and 2002 just about every owner advanced the exhaust cam to give the wr more yz like power. It more than likely did not jump time!

ickfinger, on 24 April 2012 - 12:23 PM, said:

he's at TDC in the pics so how would you explain his intake cam then....it should be inline with the head at TDC.
only the exhaust cam should be off the mark if he YZ timed it.....and that's assuming it doesn't have a YZ cam put in it.
and it looks like 13 pins between marks..... so guess again!

When I pull the head, I just can re time everything independently on re-assembly, right?  

Line the crank up first, then the exhaust cam, then the intake cam?

Although, I'm more worried about finding what's causing the kick starter to stick than a jumped tooth or two, so tonight I might take a detour from the engine tear down to investigate the clutch and transmission first

EDIT: I also have no idea if the PO is using a YZ cam or YZ timing

Edited by jamesm113, 24 April 2012 - 03:53 PM.

Even if the cam chain wasnt the issue this time...it wouldnt be a bad idea to throw a new one in with the rebuild. Inspect the guides and the teeth on the gears as well. I heard when I bought my 01 WR250f last fall that they have been known to wear prematurely, and obviously that does include hoursssss of use, lol. And its pretty cheap preventative replacement if nothing else.

I had mine apart to put a set of rings on and inspect the piston, etc because when i got it i had no idea how long it had been. Also put an 03 exhaust cam in for the decompression (the sheit if you dont have it, and i'd do that while you're in there as well)...so at that point, silly not to do a chain.

Edited by J_WR2fitty, 24 April 2012 - 05:23 PM.

Yea, I think I'll do the chain.  Still considering the '03 cam... it's $123 on ronayers.com...

Anyway,just popped the clutch cover off and there's some metal shavings:

yea well you can find them used on ebay too....for waaaaay less. Just gotta keep your eyes peeled, they get scooped up. I mean if theres no rush, then try to find one there first.

If you're going to spend $123 on a stock cam then you might as well spend a couple more bucks for a Hot Cam

http://lukesracing.c...egory_Code=HCYB

Got the head off tonight.  Here's some pictures of the cylinder.  Anything wrong?

I would say that's a good sign. I'm assuming your valves are intact, since there's no sign of the valves hitting the piston. Any thing more on the clutches?

Clutch looked OK to me,  I pulled the whole assembly.  Same thing with the kickstarter. The idle gear between the kickstarter and the clutch was a little loose.  Not sure if that is normal or not

jamesm113, on 25 April 2012 - 06:38 AM, said:

Sounds like your gonna be splitting the cases. Could possibly be a seized rod bearing.

Check these out. Could be of use to you.
http://www.ebay.com/...984.m1555.l2649
http://www.ebay.com/...984.m1555.l2649

jamesm113, on 24 April 2012 - 05:51 PM, said:

these would have me worried.  look on the inside of the flywheel and see if you have metal sticking to the magnets.