Author Topic: 89 kx250 fresh top end  (Read 4328 times)

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mxrider503

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89 kx250 fresh top end
« on: July 16, 2005, 11:05:01 PM »
hail to the bike gods:)
                       Yet another interesting problem. We just got a 89 kx250 that was rebuilt by a professional for 800$   It ran decent (hard starting) for a while. I cleaned the carb and it ran great, now he can't even ride it because it just wigs out. Wig out - complete and utter chaos bike revs extremley high the kill switch doesn't cut the engine and when we hit the gas it just bogs. This just randomly happens when the bike is ridden a little more aggressive. I had to give him my bike recently while i babied his around the trails. The exhaust seals and springs are non-existent and we had to jerry rig it with some bendable rods twisted up a bit. I noticed when i came to a stop due to a large obstacle a fluid was coming out of either the gearbox or radiator overflow this may be due to the wiggin over heating the motor or it may be part of the problem. I know that a leaky seal could be the err of this problem but i have no idea how to diagnose the seals. My question to you guys is what should i do???? We are searching for a seal and spring kit compatible with the pro-circuit pipe. I don't know if you ct people know but in about 2 weeks our local government is going to  put a  ban on atvs which means no more thomaston. This being said we are trying to get this bike up and running asap so we can enjoy our last few days of riding before we have to drive an hour and a half to ride from now on. A quick and prompt reply would be greatly appreciated. thanks guys.
-brian

mikesmith

  • Guest
RE: 89 kx250 fresh top end
« Reply #1 on: July 17, 2005, 07:06:17 PM »
Sounds messy.Is the throttle sticking or the slide?Cable throttle tube or slide may be worn and full of dirt.If its hard to start your jetting may be to lean andpart of the cause.You need to check what fluid your talking about,trans fluid or coolant?If its overhearting or has an air leak that may be the problem.Get the springs, seals and use high temp silicone on the pipe before you ride again.

mxrider503

  • Guest
RE: 89 kx250 fresh top end
« Reply #2 on: July 18, 2005, 12:37:37 AM »
check

mxrider503

  • Guest
RE: 89 kx250 fresh top end
« Reply #3 on: July 20, 2005, 06:37:29 PM »
Hey guy.....got everything sealed up and went to start the bike but couldn't.....took the spark plug out and it was spotless....refreshing yet sad we have a head gasket issue. We got the motor out but haven't taken the head off yet..We did notice one of the rods that the nuts screw onto to hold the head on was freely turning (the one under wher the radiator hose comes out of the head). My question to you guys is one can we get away with a new head gasket and retorqing the out side bolts (how many lbs?) or do we have to take the cylinder off and retap it? I only know of this i don't know how so please be specific. Is there another solution??? I've heard of heli-coils being used but i don't think i've ever had the misfortune of having to install one. In sum any advice you guys have will be greatly appreciated. Also I'm gonna start posting pics of my bike and my buddy's. Also for anybody keeping tracks of my posts...per my other post entitled 96 kx250, I replaced my old fatty with a procircuit platinum and my jetting issues have all but dissapeared :) so if your having jetting issues and your pipe is a tad shoddy try replacing it before jumping into other solutions.
thanks
-brian

mikesmith

  • Guest
RE: 89 kx250 fresh top end
« Reply #4 on: July 21, 2005, 07:51:21 AM »
Unless you plan on adding to your tool collection,the helicoil kit may not be worth buying and cheaper to just have a shop install one,If you have a pulled head stud then theres why you blew a gasket.Its 18 ft lbs for the torque.

Rowdy-Yates

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RE: 89 kx250 fresh top end
« Reply #5 on: August 08, 2005, 04:53:27 PM »
I would retap and install a new stud. BTW I dont think i understood you correctly. Was the bolt loose or broken. Either way if you had air getting in you may have slightly seized your piston. Not locked up but enough to notice.