stuck 250r jug!!

[aldochina]

this thing is stuck!! between the coats of crappy paint, and looks to be a bit of oxidation where the studs come through it doesnt seem to want to budge. i know the manual says not to tap it, buy i been crackin it a bit with the rubber mallet, and nothing! you guys got any tricks? or just keep at it with the mallet?? I'm gonna score around the base with an exacto to get through the paint, maybe that will help!

[Chazz of Blades]

I had the same problem with the jug on the 400, I tried everything from tapping it, to literally straddling the bike and picking it up by the jug to no avail. I had to take those tiny screwdrivers and VERY CAREFULLY tape them around the base, and after it opens up, go up a screwdriver size and continue this process. Don't go too big too fast though or you may damage the jug.

[RIDE-RED 250r]

I would really hesitate to use the screwdriver method and try only as a last resort in an extreme situation. Damage to the mating surfaces can easily occur that way..

Get all the paint off that you can and try a little propane heat on the jug adjacent to the studs. There are 2 steel alignment dowels mated between the jug and crankcase. Steel dowels tightly mated in aluminum holes=easy to seize in place. The 2 dowels are on the gearshift side, front and rear studs. Sometimes the dowels remain in the jug, sometimes in the crankcase.. But either way, my bet is the dowels are causing your problems, not so much the paint and whatnot...


Just be careful not to use too much heat, even with propane. You don't want to warp that aluminum jug. After heating both up a bit, try tapping side to side with your rubber mallet.. Once one side begins to separate, (usually the side without the dowels) you can slide thin pieces of plastic or wood in the gap and that will give more leverage to pop the doweled side loose. Anything you can fit in the gap that won't damage the case and jug mating surfaces will suffice...

I recommend replacing the dowels with new ones as the old ones are likely rusty and will go back in hard and could cause you to get a false proper torque when re-assembling the engine. Also, clean the grooves the dowels ride in thoroughly with a dental pick or whatever you have that can get the job done.

Good luck. They can be miserable, especially if the jug hasn't been removed in a number of years.

[aldochina]

thanks man, just the kinda info i was hoping for!!

[Xowner]

SPRAY THE trailprotrailprotrailprotrailpro OUTTA STUDS WITH PB BLASTER!

[Dirtcrasher]

Brass drift. Careflully placed; there are a few reinforced areas you can whack, then wiggle by the reed cage and exhaust port........

[aldochina]

thanks guys, i got it off. once it broke loose, it wasnt too bad. definately rusty dowels. i took some quick measurements, and the cylinder looks to be at stock bore 2.599, but the piston appears to be at the service limit of 2.594! first time into this, so i'm flying by the seat of the pants(and the manual)lol! the cylinder looks good i think, bottom end seems within spec. i will post some pics tomorow to see what you guys think!

[RIDE-RED 250r]

Make sure you measure the cylinder for overall diameter, out of round and taper per the manual specs. If it's close to max service limits at any axis, best to get it punched out .010.

Glad you got it apart... I had a CR500 engine about 10 years ago that gave me the worst fits of ANY engine I ever had to disassemble.. Doinked around with that thing for almost 2 hours before the topend came loose....

[Dirtcrasher]

It's even more fun when the piston is locked up :lol:

I always lightly grease new dowels upon reassemble. I center punch the lower case thin area on the 250R base area to prevent sucking in of the base gasket.

YAMAHONDAMAN taught that one to me and deepa.....

[aldochina]

ya, i gotta take some more measurements. i have nothing to measure the middle of the cylinder, but i can get the top and bottom, will this suffice??