bike locked up and wont shift into 3rd gear, any ideas what it could be?

mthalt10

mthalt10

PR Member
i have a 08 KX 250f it has a fresh top-end including a new head..the only thing that has not been replaced is the crank..while riding at battlesburg yesterday i came over the whoop/roller section and the motor completely locked up on me when i was in the air going over the first double..luckily i did not crash..but now the bike is locked up and it will not shift into 3rd gear when trying to shift thru the gears manually. i am not sure if there is something caught between the gears, or if i broke a gear, or what?? any ideas to what could be wrong with the bike? i plan on taking it apart sometime this week to figure it out, i was just trying too see what some of your ideas were on what could be wrong with the bike??
 
I'm confused......you said the motor locked up, but it won't shift into 3rd gear. Are you saying that the engine will run but the transmission won't go into 3rd gear? Stalls when you try to go to 3rd? Or the engine won't run period.
 
Too many things it could be. Your going to have to tear it down. Start by taking off the clutch cover and remove the entire clutch basket. If you cant find anything there then remove the top end and check every thing there. Less likely to be here but your going to need to remove it anyway. After that the motor comes out and split those cases !
 
Scotty810 said:
I'm confused......you said the motor locked up, but it won't shift into 3rd gear. Are you saying that the engine will run but the transmission won't go into 3rd gear? Stalls when you try to go to 3rd? Or the engine won't run period.
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sorry for the confusion... the bike will not run at all..it will not kick over at all and is locked up at the kickstarter..the rear wheel will spin freely in neutral.. but, when just operating the shift lever without the bike running..the shift lever will go down to 1st-N-2-then it will not shift into third or past third into 4th
 
you more issues than a tranny problem, if it's in neutral and the motor is locked up. My first guess would be crank. You stated it has a new head/piston, why ? did you dropped a valve ? If that's the case your crank could have had damage from the piston hitting the valve.
 
Yeah but it wont shift right. You have tranny issues too. Sounds like you got big $ in your future !
 
@evomx244
If you lock up the motor, that doesn't interfere with the transmission. you could pull in the clutch and shift gears all day? Please explain? What would that have to do with not being able to shift past 3rd gear??? Just curious.
 
evomx244 said:
you more issues than a tranny problem, if it's in neutral and the motor is locked up. My first guess would be crank. You stated it has a new head/piston, why ? did you dropped a valve ? If that's the case your crank could have had damage from the piston hitting the valve.
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the bike has a new head because i dropped a couple of valves and t messed the old head up completely. i am going to have to disagree with you though, because i believe if it were the crank or anything in the top-end it would shift passed 3rd gear. i guess i will find out this weekend when I tare into it..
 
"the rear wheel will spin freely in neutral" Still think it's the crank (could be wrong) , your taking a chance using your old crank after dropping valves reguardless.
 
well as much as it kills me to say this........we were all right about why the motor was locked up..the rod broke off the crank and when that happened the remaining of the crank went into my transmission and mangled that up pretty bad..not to mention the whole it blew in my cases..so now i am looking to buy a whole new bottom-end and then it should be good to go, i hope...thanx for your thoughts guys
 
Wow! You must bleed green haha. If I dropped a valve and but a new head on the bike. Then snap my crack, id go buy a Honda. I have most of parts you need, PM me if interested.
 
To me the gamble with the crank was where you went wrong. It sucks but more often than not your better off spending the extra coin when your in there esp on a 4 stroke. I've seen too many smoked Kawasaki and Suzuki 4 strokes. Not hating on them but of all the bikes I hear having issues these 2 seem to take the cake in the 4 stroke category when it comes to valves and cranks.
 
mthalt10 said:
well as much as it kills me to say this........we were all right about why the motor was locked up..the rod broke off the crank and when that happened the remaining of the crank went into my transmission and mangled that up pretty bad..not to mention the whole it blew in my cases..so now i am looking to buy a whole new bottom-end and then it should be good to go, i hope...thanx for your thoughts guys
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This just made me feel like I was at the end of an old "60 minutes" episode.

"And now you now the rest of the story"!

Problem is its not good...
 
MX724 said:
To me the gamble with the crank was where you went wrong. It sucks but more often than not your better off spending the extra coin when your in there esp on a 4 stroke. I've seen too many smoked Kawasaki and Suzuki 4 strokes. Not hating on them but of all the bikes I hear having issues these 2 seem to take the cake in the 4 stroke category when it comes to valves and cranks.
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i know one thing now..i will never buy another kawi or suzuki..this was the first kawi that i bought and its going to be the last..lol..going back to honda or yamaha
 
I've seen plenty of Hondas with the rod sticking out of the cases.....

Here's the problem. In order to overcome the inherent extra weight of the four stroke engine, all components have been shaved and slimmed down as much as possible to save weight. On four strokes it is much more important to stick to the maintenance schedule to avoid catastrophic failure.
 
PitRacer said:
I've seen plenty of Hondas with the rod sticking out of the cases.....

Here's the problem. In order to overcome the inherent extra weight of the four stroke engine, all components have been shaved and slimmed down as much as possible to save weight. On four strokes it is much more important to stick to the maintenance schedule to avoid catastrophic failure.
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Makes sense. Much less expensive (and easier) to change oil and filter and clean the air filter. Than rebuild the motor, trany.
Still very painful to hear. And these after the fact pointers aren't much consolation. Sorry.
 
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