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[B]97 cr250 screaming uncontrolably[/B]

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i have a 97 cr 250 that had a blown base gasket i replaced it when having the jug off cleaned it with this really strong aluminum cleaner. but anyways bike ran when i took it apart fine but now kick it and she screams til you pull the plug wire the kill switch will no work at the high rev. the carb is not stuck open or anything. maybe the aluminum cleaner got on my reeds and messed them up? the bike has boysen rad valve reed kit. but please anyone help... i dont you could have a air leak so bad to cause this...

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i dont think reeds could cause this. it has to be cable to carb thing. its gotta get the air/fuel from somewhere to scream uncontrollably.

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check cable make sure its routed correctly, not binding. does the throttle seem to work fine? also, air leaks can cause a high idle, make sure carb boot/intake tightened.

are you saying screaming like 1/2 throttle or just high idle?

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I had this exact same thing happen to my 98' cr250. You can check my threads about it. It happened to me once just starting it up. I didn't even have a kill switch installed on the bike at the time. It WAS a freaking nightmare. Then I rode for like a month, bike ran great...Then all of a sudden a month later I am at the track doing a little wheelie up a hill and I got 40% of the way up and it went WFO on me again. Bike did a complete backflip ripping off the rear fender. Ran great again after that and since.

The only things I can think are my slide got stuck somehow. Also my throttle cable/tube/and whole assembly was like a decade old and dirty as hell. Also my cable was routed wrong. It was going over the spark plug and coolant hoses instead of under them. So we replaced all of that and correctly routed the cable.

Everyone on here was basically ignoring that and saying I had an air leak. We literally rebuilt my top end and replaced my reeds this past week. Whole new bike, so it's hard to say if it was one thing or the other. Could've been my base gasket, but one of my reeds had a crack in it, and also my reed block gasket was torn but not in half, so my knowledgeable mechanic buddy said it wasn't a problem, which I still don't believe. Anyway, I'm not sure if a cracked reed could've caused all that. The bike was harder to start and had a surging idle that I know was the reed, but not sure about the WFO throttle...

Take your carb apart make sure the slide AND needle are not catching, worn or bent...Check and lube your throttle tube/housing/ and cable....

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are you saying screaming like 1/2 throttle or just high idle?

He is saying his bike is going to the highest utmost possible RPM

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i put new crank and top end kit in the bike in july 2011. then i rode it til about 1 month ago with a friend rode it and said the power valve was not opening. so i to the jub off fix that. then about a week ago i blow a head gasket and i thought it was base so i replaced both gaskets. as far asthe throttle its opens and closes fine.the bike also seams to re over rev limiter. i really want to go ride soon as my brother got a brand new ktm and its talkin crap now i guess i will start with buyin new reeds the rebuild and jet my carb. the bike also ran perfect befor the gaskets and cleaning the jug besides running hot.

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Yea you've replaced most everything else that can leak other than reeds, carb boot, and carb situation. Not sure what you've done about those, but one of the other things that could be leaking is your crank seals. Ignition side is really easy but you don't have to split the cases to replace them or anything.

Could a crank seal have a big enough leak to cause a WOT condition like the OP is talking about? I would think it'd have to come from his intake/carb

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Yeah...Definitely check the air leak route but I feel like people over diagnose the air leak situation all the time...I found they weren't even listening to the facts I was presenting but still calling it an air leak. Check your reeds, your carb, and especially your entire throttle assembly.

Just as I learned, powervalve can't cause this problem. An easy way to check for obvious external air leaks is to start the bike and spray it down with carb cleaner, if it revs up you've found your leak...You can use starting fluid but that will cause it to want to die, then you've found your leak that way...But with this method is only checking for obvious external leaks as I found later I sprayed down my intake area, no rev up but later we checked the reeds and I had a nice crack in one. I hate that you're experiencing this I know how it feels. You can't ride the bike and realistically try to get better without thinking it's going to do it on every lip of a jump or whenever....We rebuilt my entire bike minus the bottom end and I still feel sketched out.

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Yea you've replaced most everything else that can leak other than reeds, carb boot, and carb situation. Not sure what you've done about those, but one of the other things that could be leaking is your crank seals. Ignition side is really easy but you don't have to split the cases to replace them or anything.

Could a crank seal have a big enough leak to cause a WOT condition like the OP is talking about? I would think it'd have to come from his intake/carb

yeah i don think that crank seal would cause anytype of WOT scenario.

even a huge air leak wouldnt give it a WOT problem, it would definatley give high rev thou 1/8 throttle possibly.

to get a WOT rev it also needs fuel, so in my mind a WOT scenario is morethan likely cable/carb problem (slide/needle getting hung up).

this is only my opinion, and how i look at things, im wrong alot of the time but i also nail a few too. goodluck

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yeah i don think that crank seal would cause anytype of WOT scenario.

even a huge air leak wouldnt give it a WOT problem, it would definatley give high rev thou 1/8 throttle possibly.

to get a WOT rev it also needs fuel, so in my mind a WOT scenario is morethan likely cable/carb problem (slide/needle getting hung up).

this is only my opinion, and how i look at things, im wrong alot of the time but i also nail a few too. goodluck

Exactly. Not sure why the over diagnosis of air leaks around here.

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What happened with mine was either the slide/needle getting stuck or had something to do with my insanely old and dirty throttle tube/housing/cable or the cable itself not being routed exactly right...

Cuz you think it's scary when it does it on the stand...try it in the middle of stand up wheelie! FML...Could've killed me had I been off a jump, or into a tree. The throttle doesn't just stick where it's at, it goes to the highest possible RPM the motor can go, and on a 250 that's pretty high.

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so a friend came over and looked at my bike. turns out the boot between the carb and rad valve was torn almost half way around it so theres my airleak. i ordered a new one and will post more when i put it on. thanks for all the help u guys.

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