Yamaha WR250, Bike is very hard to start... Help needed

Joined
May 9, 2007
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#1
Gday,

I just bought a 2001 Yamaha WR250. It is a great bike, heaps of fun etc etc.

Anyway it starts easy when i first take it out and the engine is cold, but once i have been riding it for more then a few minutes, if i stall it and i need to restart, it is practically impossible. I have tried hot start, cold start etc with no luck, the only way i can get it to start again is to wait half an hour or so, then it just starts first time. I decompress it before i try and start it, but doesnt seem to help.

Any advice tricks or suggestions would be greatly appreciated, thanks.
 

splatt

Resident mental case
Joined
Dec 1, 2001
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#2
Have you checked your valve clearances. If they are getting too tight that will make it hard to start especially when you get the bike warmed up.

Steve
 
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Sep 4, 2005
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#3
Had the same issue with my '02 YZ250F. I replaced the exhaust cam with an '03 and the starting issues disappeared. The cam profile is the same, but the starting routine is just so much simpler. Pull the hot start and kick. No TDC, no decompress, just kick. There are those who will tell you that changing the cam doesn't have anything to do with ease of starting, but my experience has been very positive. Best $130 I've spent.

The pilot jet may be a bit on the rich side also. That helps when the bike's cold, but is a problem when it warms up. You can try turning in the adjusting screw 1/4-1/2 turn and see if that has any effect. What elevation are you? Might the bike be jetted for somewhere lower?
 
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#4
I am pretty tall, the guy who had the bike before me was short as. Also today, something bad happened.

I was riding it, didnt really wait for it to warm up, stalled it, heard a bang, and since then i have been unable to start it. Feels like there is no compression or something. The kicker just keeps turing around with insufficient pressure. Think i might have busted something in the engine
 
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#5
That sure sounds like only 4 of your valves are still intact. Put it on a center stand, put it in 2nd or 3rd gear and see if it will turn over by rotating the wheel. If so, get ready to take out a 2nd on your house to rebuild the engine. Regardless of whether it was a valve, there's going to be some disassembly in that engine's future.
 
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#6
should have listened to the first guy. tight valves and you may have now snapped the head off a valve. if ya didnt hurt anything else it wont be to bad (new valves-50$ a piece, lap in new valves - 30$ if ya do it yourself , gaskets- 65$+ get a complete kit so you get the valve stem seals also) if your not gonna do it yourself and ya hurt more stuff then yes it will be 500$+
good luck
 
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May 9, 2007
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#7
Thanks for the advice guys. Not to concerned about cost, but i am real busy now and wont have time to take it to a shop for about 2 weeks, but i have a dirtbike holiday that i have to go on in 4 weeks. So worst case scenario, how long will it take for a shop to fix it?
 
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#8
It depends on how much damage there is. A broken off valve head can do serious damage to the piston and cylinder head and other valves. If that's the case, it's unlikely that all the parts will be in stock. Actual time required to replace the top end is less than a day. Getting the parts and getting to it will be the bigger issues.
 
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#9
If ya not worried about cost buy a new engine and swap it over.
Or just get one of ya mates to drop off ya bike.
Sorry about ya bad luck with ya bike.