Buddy was riding my 1985 yz 250 he said he was downshifting from high speed n engine idle fast then die all gears seem to work (towed it with 490) got in neutral easily obviously am newb w/ engines I know you guys know what has happened Thanx again for all kick ass input like always
250 kicker like cement
- Thread starter Slipperypickerl
- Start date
Piston? What's worst case scenario?
How do you know the gears are working? Does the piston turn over in gear while being rolled in gear? Is the kick starter the only thing sized?
two things can happen here, you can pop that two stroke motor cherry, or the junkyard gets a new resident.
You've got nothing to lose, heck it's already broke. get cracking!
two things can happen here, you can pop that two stroke motor cherry, or the junkyard gets a new resident.
You've got nothing to lose, heck it's already broke. get cracking!
Here's what I think.
I'm thinking top end needs to be rebuilt. Worst case $350 to rebuild.
But, the kicker is frozen stuck which leads me to believe that your buddy's rapid downshift to over whined engine may have beaten down the bottom end.
Expect any of the following:
Broken crankshaft or crankshaft drive gear busted.
Broken primary drive gear shaft.
Busted inner/outer clutch hub.
Broken secondary gear shaft.
Good news is that it can be fixed.
I'm thinking gears are OK cause I can shift it into 1st n it seems like it is in gear then I can shift it back into neutral can't tell if piston is moving ya push on kicker it is dead stop if looking from side kicker stop at 11 o clock
Pull the cylinder, if the crank moves freely then it's a top end, but like Mike said be wary of lower end problems also, if when you pull the jug the crank still doesn't move, then it's a seized crank bearing. Let's start here.
Thanx for all input will start tearing her down
....stupid everything cost money
....stupid everything cost money
Got her all apart piston is shattered used magnet to get all pieces I could see crank moved free but not do a full circle I got it to move all way found hunk of metal stuck to crank got it out seems to move free all way in circle but one spot seems little tight like is more metal possibly pretty positive bike is stock seen all kinds of different pistons how do I know which to get
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First flush out the crank case with pre mix or diesel fuel until your sure all the debris is removed, then inspect for any damage to the case caused by the piston, I've done this multiple times over the years and the bottom end always turned out ok.
So take out oil pan plug and pour pre mix in where I put in my gear oil to flush.. sorry bro like I said am plumber new to this engine stuff I'm 51 this is first engine I've ever taken apart was fun but a bitch to get to some of bolts desert gas tank bolts were hardest Thanx for all the help
