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2005 RM Z250 hole in crank case above tranny, runs fine

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My sons 250 started leaking oil during a race. He finished the race, there was oil on top of trans and i had just filled it prior (minor sprocket shaft seal leak), So I figured i had overfilled it and it spit some out the vent. He run his final race. So then I had time to give it a close inspection. It broke a tiny hole in the RH case on top above the tranny gears, about where the rh end of the the output shaft would be. (opposite end from the sprocket). I caught the hot oil and it has NO chips of steel or aluminum in it and looks normal. Bike runs normal. Not sure if it picked up something stray from the bottom of the case or what caused this. The hole is at the parting line on the rh side. I understand the engine is kawasaki made and the cases from the Kawi is the same. Are some weld repair possible without warping the case? Its not much of a hole unless that is a high stress area. It is just behind the kick starter gear and I wondered if it cound be stress cracked from the starter, but it does not apaear that way from the outside. I'm a diesel tech so I'll likely tear it down myself. We got the bike second hand but have put about 25 hours on it and did a valve set, bike seams pretty solid up to this point.

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Jb weld until you afford a used case half off ebay. More a problem to build than to afford. Gravity is on your side.
Well we tore it down without riding it further. Good thing, 3rd gear had a broken tooth and the rest of 3rd were chipping, as well as the gear it run on. Poor drain plug design makes it hard to drain chips with the oil. So 2 new gears. Magnetic drain plug.
Sent the crank out to have it checked. It was due so rebuilt. Head and cylinder checked out good. New seals, gaskets,timing chain, piston. Hopefully start putting it all back together this weekend.
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Well it took me long enough but finally got back to this project this past week and installed the rebuilt engine back into the frame. Installed rebuilt forks and shock from Factory Connection. So from a pile of parts to a running bike with the only minor hickup being the stator plug is quite stiff to seat and we had no spark because we did not get it in fully the first time around.

 

The only other issue seem to be hot start is not great. Idles and runs ok, but shut it off and ir will need several kicks. Cold seems good. When a bike is at a warmed up idle should depressing the hot start cause the engine to slow down of it that a indication of too lean at an idle

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