Problem from HELL 2000 CR250 won't stop reving up

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Sep 5, 2007
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#1
My cr250 had a serious problem, every time I hit at least 3/4 throttle and some bumps the rpms stick and I can't get it to rev down until I grab the clutch and stomp the rear brake, then it finaly raps down. I've replaced the throttle housing, cable, cleaned the carb, checked the pin, serviced and cleaned the air box and everything else I could think of. What am I missing? The throttle is not sticking, it has a factory cable that links up great. What could the problem be? An air leak of some sort, something is causing some serious cruse control and I could use some advice as to what that could be. Thanks
 
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Dec 18, 2002
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#2
definately not the above reply...it is an airleak..please do not ride the bike as is..it sounds like a seal has gone in the engine..apart from getting hurt your engine could seize so get it fixed
 
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Oct 21, 2002
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#3
like blanc said could be an air leak. if the problem occurs on bumpy ground, then check the condition of the rubber intake manifold the carb fits in to. if its cracked it might be flexing when the bike shakes and sucking in air causing your bike to rev. one other possible senario is the throttle cable is jammed some how under the tank or is generally too tight and when the bikes suspension moves its holding the throttle on a bit.
good luck and be careful, stuck throttle condition scares the crap outta me! :yikes:
 
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#4
lol the last time i had a stuck throttle it was on a gasgas trials bike, not fun...lol
 
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#6
Yeah look for an air leak in the fuel line or carburator...

i know when my bike was running out of gas i hit the throttle to try and get me a boost closer to the shead and it did it... Scared the crap out of me... The kill switch didnt work..

but i was empity on the gas so i was sucking air... so it was acting as if there was an air leak
 
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Mar 12, 2001
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#7
Even when the throttle cable gets stuck, the kill switch doesn't work. Scary stuff, has happened to me more than once. Now inspecting my throttle housing is part of my normal maintenance.
 
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#9
checking for air leaks can be tricky depending on where the leaks coming from. a manifold leak is often fairly easy to see with a torch as you can move the carb slightly and see if any cracks in the rubber open up etc.. crank seal leaks can be checked visually on the l/h side if you remove the flywheel and then the stator assembly. a leaking seal normally has some oil residue around it (which is why the r/h seal is harder to check as it lives in the gearbox and requires more work to actually look at it..)
base gasket and case gasket leaks can sometimes be picked up by just looking, but the best way to check for ANY leaks is to carry out a leakdown test of the crankcase using low pressure compressed air. this takes a wee bit of doing and unless you are fairly competent then i reckon its a job best left to a workshop. however check the basics first as it may be just a simple thing.
 
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Apr 28, 2007
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#10
You guys are giving me flashbacks.

Farmkid to stupid city kid when throwing her unprotected onto faulty snowmobile:

"The throttle sticks a little. Oh, and it can die when you are going downhill- You'll need to give it a little gas"...

Oh, if only I had a picture of the damage after a large tree grabbed me off that out of control sled By My Face... :yikes: :yikes: (Saving my life, undoubtedly.) :whoa:

I hid from people for over a month.

I hate farm kids. (jk)
 
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Oct 29, 2007
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#11
Maybe the floats are sticking. When you go over a bunch of bumps it shakes up the fuel in the bowl. If your floats are to low then you will have alot of airspace in your bowl feeding the engine a mix of gas and fuel fumes which is a little like starting fluid. Check your plug and see if you are running a little lean. If not I think your floats are either stuck or set to low.
 
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Oct 30, 2007
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#13
it seems odd to me that it only happens at over 3/4 throttle. usually with air leaks you have the symptoms all over the RPM range. theres not by any chance a small bur inside your carb holding up your slide past 3/4 throttle? have you have you removed your air box and looked through the carb to see how the slide is working when you use the throttle?