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2004 WR250 Engine Jammed?

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Help! My WR250 came to a screeching halt after it idled about 1 minute. The sound from the engine was somewhere between a screech and a thud. The engine restarted OK but did the same thing after another minute. I tried the kick starter and it turned over freely with good compression. The engine was cold so it doesn't seem a seizure, but more like something was getting jammed. The bike only has 250 miles on it and I've change the oil 3 times, also check the oil level every ride. At this point I hesitate to run it anymore for fear of causing major damage. Any ideas?? Can the starter motor re-engage and hang up (the sound seemed to come from the front left of the motor)? During the last ride it ran great, however the valve train did seem a lttle loud when it got hot. I'm new to 4 strokes, so this is new territory for me. Any help would be appreciated!

2004 WR250, Grey Wire Mod, Airbox Modification, YZ Exhaust.

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if i had to take a shot in the dark at this i'd say your cams have galled their journals. just a guess though. my advice is to go to the 250F FAQ (see index link in my sig below) and follow the instructions for checking valve clearances:

http://www.thumperfaq.com/valves.htm

this inspection will take you around 45 minutes to an hour.

what you need to do is have a look at where the cams sit in the head. so remove the valve cover, then take the cams out and inspect the cam journals and the mating surfaces on the cams. if there are uneven, rough, or otherwise marred surfaces you have a bit of work to do. in some cases the cam(s) will have discolored from excessive heat; you may see a bluish-gray area where the cam meets the journal. if either the journals or cams are indeed hosed up i would contact someplace like

http://www.enginedynamics.com/services.shtml

and send them pics of your cams and journals for advice and/or a quotation on repairs.

note: when reinstalling yamaha 250F cams into the head you *must* use a 1/4" drive low range (20-200 in-lbs or thereabouts) torque wrench. mistorquing of the cam cap bolts is the #1 cause of 250F cam journal problems. ps, did you or someone else recently inspect your valves?

a few more questions...

what type of oil are you using?

is there any debris in the oil filter?

does the oil appear "milky" or look like thousand island dressing?

is there sufficient water in the radiators?

regards and good luck with finding the cause,

jim aka the wrooster

'01 wr250f

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Thanks for the quick response & advice. Regarding the oil, the first couple of oil changes was Yamaha Lube 20-50 and the last change (current) is Valvoline 10-40 4-Stroke Motorcycle Oil. I was a little hesitant using the Valvoline, but it did meet all the grading requirements? The aircleaner has not passed any debris, the oil filter was clean, and I haven't adjusted the valves as yet... didn't seem like there was enought time on it yet to bother. The oil is clean, not milky, and the radiators are full. I am actually baffled. I've raced MX with CR's, YZ's, and RM's and never had one just instantly jam/screeches to a stop from an idle, especially a bike this new! Guess that's where the expression "comes to a screeching halt" comes from...

Thanks again... I'll start checking it out.

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look at the bolt on the side of the head around the corner from The silver oil line that runs upto the head. take it out and crank the motor, if oil doesnt come out within 30 - 40 seconds you have a blockage somewhere in the oil galleries.

That tube is the feed line for the cams oil supply.

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"This may be a dumb question, but did you put the oil filter in backwards? It will fit both ways but the side with the hole goes towards the motor.Check it against the service manual."

You sure ? All my WR oil filters have only had one hole and thats for the 'tang' on the oil filter cover. You cant fit the filter backwards as far as I can see.

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OOPs!I was thinking about my xr250!I win the idiot of the week award this week.Disregard!

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I did check the filter no-problems there...also removed the bolt on the head to check for oil flow which there was. Next took off the valve cover and there weren't any obvious problems, although I haven't removed the cams yet to check for galling.

I did a quick measure of the valve clearance and on the exhaust side found it to be very tight (.003 inch). It was midnight and my first time checking, so I'm not confident in the measurement and will recheck. On the timing marks, there is one set of marks like this [__] (two vertical with a line between)followed by a single vertical line ]. Which of these is correct? When I turned the crankshaft to line up the marks it was nice and smooth, however when I went past the timing marks and had to turn it backwards there was a nasty feeling of something grating; is that normal??

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