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CRF 250x won't start after being put away no compression

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Hey guys, what would make a bike not start after it was put away and have no compression? I literally drove it into my shed and the next morning it wouldn't start and has no compression. Any help would be appreciated thanks!

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If the compression has actually dropped then something has gone wrong.

 

Start by removing the cam cover and check timing and valve clearances , if all ok then remove head and check piston and valves.

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What shawn said. Sounds like a valve is hung open.

Jim.

if a valve is stuck open will I need all new valves?

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This sounds like a case of the intake valves clearance

going to 0. Check intake valve clearance.

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if a valve is stuck open will I need all new valves?

 

 Don't panic yet, could be the decompressor hung up as well but yes, if a valve is hung up, then you generally are going to want new valves, new guides, and the seats cut.

 

 As Shawn said, pop the valve cover off and have a look.

 

 And this is assuming it is as you said; drove it into storage, went out the next day and no compression and no start.

 

Jim.

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2008, not sure of when the top end was last done its my dads bike and the valves were adjusted at the start of this year and only had around 15-20 easy riding hours this year. Bike had tons of compression the last time I drove it and didn't run any different than it ever had before but when I tried to start it the next day it had no compression. The only thing it does while trying to start is back fires every 10th kick or so and it never ever backfired while running

Edited by JMOrides

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I don't know how fast it can happen but I had a 450X that had the rig stick in the piston.

In my case I washed it, put it away for the winter and when I got it out in the spring, it wouldn't start, no compression. Took the head off and found the issue.

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My dad decided he's gonna bite the bullet and just take it to someone who knows how to work on fourstrokes, we don't have experience working on them and there fairly tricky looking

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Check your valves its more daunting thinking about it than doing it ,at least then you now whats what !!! I started a race at 12pm and by 1.45 pm my valves had tightened ..I would not advise bumping a 4 stroke but if you were to bump it and it started you can be pretty good chance  its valve related ..

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Check your valves its more daunting thinking about it than doing it ,at least then you now whats what !!! I started a race at 12pm and by 1.45 pm my valves had tightened ..I would not advise bumping a 4 stroke but if you were to bump it and it started you can be pretty good chance its valve related ..

I was thinking if it was a stuck ring it would destickitize it.

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i am sure rings can become hung up but i have not really come across that in a long long time and the only time i did come acoss a ring causing issues was either with wear related problems or  the installer putting the ring in upside down (not me) bump the bike if it starts check the valve gap if you dont fancy bumping it just check the valve right hand side inlet should be the firs port of call and go from there ..

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befor you try anything else ensure the de compressor lever is not stuck in the open position try pulling it in a few times and make sure the lever has some free play hope you get it sorted ...after riding 2 strokes forever the 4 stroke felt to me sometimes like it had not compression .Make sure the valves gaps are good its a worth while practice as with all 4 strokes you will always have to check them ,make sure the battery is good even a slightly week one can make starting hard ..Make sure a mouse has not moved into your air filter and that its free from dirt and obstructions ..Fuel if you have fuel a spark it should go..if all things are good valves etc it will start let us know how you get on..good luck

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