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Atc 200x 1985
03-18-2024, 12:57 PM
Hello all once again. Just got a minor issue with my recently rebuilt 85 atc 70. I upgraded the oil pump, put an 88cc big bore kit on it, sandblasted all 3 cases inside and out, and all new gaskets. My problem is that, for some reason, when I turn it at high rpms, it seems to be throwing oil out of the crank vent on the case? Im assuming that is where it is coming from unless it is due to a bad gasket, and its causing it to leak from that. It only leaks from the top of the motor, and since its leaking from there, its making me think that it is coming from the crankcase vent. Any guesses on why? I guess oil is getting pushed up through the baffles (that are meant to stop this) inside the engine due to me turning it at a high rpm. its not much of an issue at the moment because its mainly used for trail riding, but every now and then, ill open er up and let it scream.
shortline10
03-18-2024, 03:12 PM
Either too much oil in the engine or the high compression piston hasn’t seated the rings yet and it’s making excessive crank case pressures and causing the leak .
Atc 200x 1985
03-18-2024, 05:46 PM
It turns out, the gasket was bad from where I had to take the clutch cover off. I guess I didnt notice it was ripped when I put it back together lol.
ATC King
03-20-2024, 09:08 AM
BTW...

Thank you shortline10 for taking time out of your day to answer and for giving free advice based on actual experience that you worked to get, which a shop would charge for.
shortline10
03-20-2024, 02:56 PM
No problem, I don’t mind giving free advice on this forum to keep the oldies alive .
Yeah I forget user mistakes , I was thinking logical issues :crazy:



BTW...

Thank you shortline10 for taking time out of your day to answer and for giving free advice based on actual experience that you worked to get, which a shop would charge for.
El Camexican
03-21-2024, 07:28 PM
No problem, I don’t mind giving free advice on this forum to keep the oldies alive .
Yeah I forget user mistakes , I was thinking logical issues :crazy:

Ha! Sometimes “garbage and garbage out” applies to mechanical advice as well as computers.
Dirtcrasher
03-23-2024, 03:36 PM
Lots of cars with "oil pan leaks" are actually valve cover leaks, darn gravity...