Two Stroke Motocross
Two Stroke Motocross Forum => Technical => Topic started by: Ready2rise on March 14, 2011, 11:47:09 PM
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Hey, guys I recently encountered a shifting problem with my bike, was wondering if someone could lead me in the right direction to solving the problem before i take my engine to a dealer and let them tell me that everything in the book is wrong with it. Ok, so this past Friday I took my bike out for a short ride, hadnt changed anything recently other than the clothes on my back, went out shifted up the gears a few times and back down then I parked her. Bam, problem! I cant get her into neutral? tried searching around with a light foot on the lever and then even my hand...nothing ??? i get one click up and that one click back down but nothing further or in between in either direction? If i keep tapping down i get nothing, no click just the return of the lever ive tried rocking her a bit but same results, and i have to pull in the clutch to push her in or out of the garage. What may be the problem? I didnt change a thing from how i rode it before and im no expert with gear boxes so any help will be highly appreciated because id love to get back on her soon! :'(
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clutch might be shot, crap in tranny, bent shift fork, bad bearing, shift lever might be too loose to properly engage, start it up and see if you can get it neutral, if you can, change the oil. The 03 KX250 was known for notchy shifting, how many hours are on the bike?
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Yeah, it could be a number of things. Will it go into N if you rock it back and forth in gear to move the trans components?
Like Myc said, check the lever.
Does it shift through all other gears ok? Just no N?
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Good suggestions here by both Myck and Charles. Give those a try and report back.
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Ok I'll give those a try, but i can for sure tell you that i cannot get her into neutral. Like you know how when you go all the way down to first the lever doesnt move at all then you give it that "lil" half a click for neutral...well the lever on my bike still goes down like im still up there in fourth gear or something just without physically clicking into gear as usual. the lever returns but it doesnt go into any gear, thats when i hit down on the shifter. now when i pull up on the shifter it clicks up "once" but thats it so im guessing its up there in fourth and fifth gear because when i pull the shifter up i cant go any further than that??? when i started her, i did it while it was on the stand but the rear wheel was spinning like crazy but either way i couldnt get her out of whatever gear its stuck in. If the clutch may be shot then would it still roll when i pull in the lever if its trapped in gear? Oh and i really cant give an accurate reading of the hours on the bike because of course...i bought her used. but i havent actually had her to the track as its been snowing and raining like crazy here in st louis missouri. Oh i want to add that i thought all 2strokes could be started in gear??? well i cant, she rolls forward when i try to kick her over in gear and has done that since ive had it. thanks again and if any more suggestions/questions ill try a little harder to thoroughly explain what its doing.
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Drain the trans. oil and coolant out of your bike and lay the bike down on it's side on milk crates (clutch side facing up),the idea being that you can still rotate the rear wheel and get at the shifter while the KX is elevated.Remove the complete clutch side cover assy (waterpump included) and then remove the complete clutch assy.If you now look closely you will see your complete shift selector assy. and the shift selector ("star").Have someone rotate the rear wheel while you move the shift lever,you should see the shifting pall indexing on the shift selector star.Your shift selector assy. could be damaged,the neutral detent (the neutral detent is shorter then the gear detents) could be chipped (powder metal casting) or the problem may lie between your centre cases in your shift drum/forks assy..As well,see if you have play in your transmission shafts - you could have a bearing failure.Good luck! :D
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If there is not a lot of oil between the clutch plate, the bike won't want to start in gear. Thats about all I know haha.
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Go right up to top gear then count as you change down, i'm guessing you're stopping at 2nd cause of shift fork or drum issue's.
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yeah, they don't like to be started in gear when they're cold. but once you get some fresh oil on the clutch plates....... :D
I've never been able to push my bike easily while in gear with the clutch pulled in, it aways drags a little, no matter what gear it's in. But I can sit, idling, in gear, with the clutch in, all day. IDK I bought it brand new and keep 3mm of free play at the lever.
Maybe it's just all this sand down here in Florida. ;D
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ok while this video is basically the same as the post i made it at least somewhat shows the shifter action that i get when going up or down and so you know i cant go any further up than what ive shown in this vid. Bike won't shift stuck in one of the upper gears (http://www.youtube.com/watch?v=LsLAIR66iOU#)
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I've recently repaired two ATVs with symptoms similar to your KX ie: stuck in gear.The gearboxes in the ATVs are basically identical to your bike.In one ATV the selector pin was sheared off of the shift drum indexing "star" the result being that the shifter pawl could not index (move) the shift drum and so the bike was stuck in that gear.In the case of the other ATV the shifter pawl itself was broken so it could not move the indexing "star".In both cases I was able to replace the offending part without having to split the centre cases.In both cases these parts broke as a result of the shifter being kicked.
I could be wrong but I'm quite certain that if you pull off your clutch to expose the KX's shift mechanism you'll find the problem.
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I've recently repaired two ATVs with symptoms similar to your KX ie: stuck in gear.The gearboxes in the ATVs are basically identical to your bike.In one ATV the selector pin was sheared off of the shift drum indexing "star" the result being that the shifter pawl could not index (move) the shift drum and so the bike was stuck in that gear.In the case of the other ATV the shifter pawl itself was broken so it could not move the indexing "star".In both cases I was able to replace the offending part without having to split the centre cases.In both cases these parts broke as a result of the shifter being kicked.
I could be wrong but I'm quite certain that if you pull off your clutch to expose the KX's shift mechanism you'll find the problem.
Exactly.
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I've recently repaired two ATVs with symptoms similar to your KX ie: stuck in gear.The gearboxes in the ATVs are basically identical to your bike.In one ATV the selector pin was sheared off of the shift drum indexing "star" the result being that the shifter pawl could not index (move) the shift drum and so the bike was stuck in that gear.In the case of the other ATV the shifter pawl itself was broken so it could not move the indexing "star".In both cases I was able to replace the offending part without having to split the centre cases.In both cases these parts broke as a result of the shifter being kicked.
I could be wrong but I'm quite certain that if you pull off your clutch to expose the KX's shift mechanism you'll find the problem.
Ill definately check this out today, was there any debris or pieces left behind from the things that were broken?
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In the first case I was able to find the broken pin and in the second the return spring kept the two halves of the shifting pawl in place. :D
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Ok, had the day off today so i went and pulled the engine out of my bike to get to the bottom of this shifting problem. Well, my problem is solved, but not without considerable doubt that it'll be back sometime soon. You see I say this because I never actually touched anything??? I laid the motor on its side and I was getting ready to pull off the right side cover and the clutch assy and it made a click! I left the shift lever on as I had it hoisted up so that it didnt come into contact with anything and bend but also to operate it while checking around and now it shifts??? 1-N-2 etc...works like the problem was never there. I set it upright and tried it again...works! Why in the world would it do that? Something loose maybe? Anyone ever had a problem mysteriously fix itself as soon as you take the time to disassemble it lol? I'm happy but I will still get in there just to check things out..for loose bolts or anything.
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If it ain't broke, I can't fix it.
sounds like something on your gearbox came loose and is in there, get a magnetic drain plug, or just drain the oil, and see if it comes out to determine what it is, if nothing comes out, roll out, roll the motor around and use a telescopic magnet to try and fish it out.
(http://i20.photobucket.com/albums/b243/myckmcclung/03kx250trans.jpg)
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You coulda pulled the engine case with the motor still in place. Couldn't you?
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no the motor mount bolts go through the case halves, he could have taken off the clutch cover with the engine in the frame, but it still sounds as if he's got a major problem.
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no the motor mount bolts go through the case halves, he could have taken off the clutch cover with the engine in the frame, but it still sounds as if he's got a major problem.
Yeah thats what i meant, you can expose the shifter mechanism this way though without pulling the motor.
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I've recently repaired two ATVs with symptoms similar to your KX ie: stuck in gear.The gearboxes in the ATVs are basically identical to your bike.In one ATV the selector pin was sheared off of the shift drum indexing "star" the result being that the shifter pawl could not index (move) the shift drum and so the bike was stuck in that gear.In the case of the other ATV the shifter pawl itself was broken so it could not move the indexing "star".In both cases I was able to replace the offending part without having to split the centre cases.In both cases these parts broke as a result of the shifter being kicked.
I could be wrong but I'm quite certain that if you pull off your clutch to expose the KX's shift mechanism you'll find the problem.
Im extremely appreciative that youre a member of this website! I bought a new shift mech. and it cured my ailments! The old parts had lots of wear and even some of the thread lock stuff was chipping and floating around in there. I got everything fixed and running again, it was a first time experience for me to have my bike apart trying to be a mechanic lol but thanks to the guys that left feedback Im up and running again ;D Thanks!
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Try changing the oil once in a while, that will really help add longevity to your transmission, and give you an idea what's floating around in the bottom
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Glad to be of service. ;D