how to split cases

[tkcoz]

I am having problems spitting the cases on my 1985 atc 250r. I have never done it before. I have everything off exept for the electrical magneto thing and the counter balancer. i have the screws out of them but can't get them off. do i need to use a puller on them. i am lost. my cases do come apart about a half inch. i don't want to crack them, i need some advice.
i am splitting them because my crank keeps locking out and i think i need to put new bearings in the end of the crank. the main bearing is still good though, i think.

thanks [/img]

[J.D.]

I am exactly 78.483456304% sure you have to take the magneto off before you can split the cases.

[trikeman]

yea you have to take off the magneto, because it's on the crankshaft, after that you have to take the bolts that are in there and it should come apart.

[Dirtcrasher]

You really want to know how?? First get a manual and follow it step by step paying particular attention to where the thrust washers go longer bolts etc. Clean it spotless, set it on a clean workbench preferably with a large white cloth that NOONE will disturb including your pets.
Now follow the book, and lay out all the parts in order.
If you don't have a 25$ book your guessing your way through it and more than likely will damage some important expensive part.
Never force any items at all, use a plastic hammer and don't even go remotely near any air or oil tight surfaces with Mr. Screwdriver.
Or just guess, make mistakes so the kickstart doesn't work and it leaks air into the cylinder leaning out the mixture and seizing the motor.
Not trying to be a jerk, but you guys should realize if your not sure if a magneto has to come off and how to do it to split the case your headed down that long expensive local dealer road.
I screwed up my very first case splitting job 16yrs. ago. Ended up costing me 3X what it would have. Impatience gets you everytime!!
Good luck!