07 crf250 wont kick over!! Idk what else to try

Chance_Duvall
Edited Date/Time 3/13/2016 8:58pm
Hi my 07 crf250r refuses to kick over it was always a bitvh to start anyway !(only cold easy when hot) i tried changing the spark plug nothing changed and i even checked the ohms on the stator and its fine
It will bum start and start after warmed up but never when cold !! Help!!
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slipdog
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slipdog 3/13/2016 3:21pm
3/13/2016 3:21pm
You (most likely) need the valves and valve springs replaced and the seats re cut. if the seats have already started to chip then you'll need to replace the seats or the entire head.

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KICKERMAN360 3/13/2016 3:56pm
3/13/2016 3:56pm
Possibly up to $1000, depending on what you need done. On a 10 year old 250F, worn valve seats would be no surprise. Have you checked the clearance? Difficulty starting the engine is normally due to out of spec intake valves. If they won't shim nicely then you have worn the seats out. http://www.kenoconnorracing.com/prices.html has some decent prices I guess.
MxKing809
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MxKing809 3/13/2016 3:58pm
3/13/2016 3:58pm
It's the valve clearance that is causing your issue. This is caused by the seats being too hard and wearing the coating off the valve and moving it up, loosing your tolerance. You need the newer softer seats and new valves.
kzizok
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kzizok 3/13/2016 4:12pm
3/13/2016 4:12pm
Chance_Duvall wrote:
Theres no chattering at all wich is why i didnt think it could be valves
Its the valves.
hillbilly
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hillbilly 3/13/2016 7:00pm
3/13/2016 7:00pm
Chance_Duvall wrote:
Theres no chattering at all wich is why i didnt think it could be valves
They wont chatter, what happens is the wear on the valve seat lets the valve travel further to close. This causes a situation of no clearance at the cam and when the engine is cold they can even be open a thousandth which is why it wont start.

It is easy to shim if you have some skill with wrenches and a hot cams shim kit.

Before tearing it down and replacing anything set the clearance correct or have someone do it then ride it a bit.

Ive done a dozen bikes that have been way out of spec and they ran fine for a long time.
jloucks742
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jloucks742 3/13/2016 7:15pm
3/13/2016 7:15pm
The easy fix is a valve shim kit. The better fix is to have the valve seats re-cut and new valves/springs. Very common on the early Honda 250f's
Titan1
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Titan1 3/13/2016 8:16pm
3/13/2016 8:16pm
I wouldn't waste your time or money reshimming stock (or titanium) valves on that bike...they will be out of spec again in a matter of a few hours.

Replace the valves, springs, and recut the seats...and if you never want to have valve issues again get a stainless steel valve and spring kit. I was doing valves once a year on my 06 crf250...then I put stainless in it and never had another issue.
hillbilly
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hillbilly 3/13/2016 8:33pm
3/13/2016 8:33pm
Titan1 wrote:
I wouldn't waste your time or money reshimming stock (or titanium) valves on that bike...they will be out of spec again in a matter of a...
I wouldn't waste your time or money reshimming stock (or titanium) valves on that bike...they will be out of spec again in a matter of a few hours.

Replace the valves, springs, and recut the seats...and if you never want to have valve issues again get a stainless steel valve and spring kit. I was doing valves once a year on my 06 crf250...then I put stainless in it and never had another issue.
Yeah, sometimes if the bike has been rolled off a lot carbon builds up so when you sre shimming it is on carbon.

Start the bike,the carbon gets beat off and then check clearance again. This time they will usually go a while.

If you aint got money to blow on a bunch of parts and dont ride it ever day shimming it till you cant get a thinner shim will get you a lot of ride time for nothing more than the cost of the kit.
moore433
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moore433 3/13/2016 8:58pm
3/13/2016 8:58pm
If it's at the point of not starting when cold, you can shim it and maybe get a little more use out of it, but the valves must be replaced.

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