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View Full Version : 400ex blowing oil !!!!!!!!


markvette
12-26-2003, 03:58 PM
got a problem that is driving me crazy. got a 400ex, it had a sparks 440 kit with a ross piston. it would blow oil through the crankcase vent tube into the air filter and air box. i had 2 different sets of rings put in it andit still done it. took the 440 cylinder off and put a cylinder with a stock sleeve on it and had it bored to a 416 with a wiseco 11 to 1 piston. it still done it. i tore it down and checked the rings and everything was fine. put it back together and it still does it. not a lot of oil but enough where the filter gets wet and the air box has a coat of oil on the bottom. what is causing this ??????? also cant seem to keep a base gasket from leaking on this engine. any tricks for this, i thought you were not suppose to use any sealer on it but am at the point of using some type of good gasket sealer on it and trying that. HELP


Mark
xc400ex
12-26-2003, 04:04 PM
On the base gasket part I dont even use one i just use RTV sealant. You might try that. About the blowing oil everyone that this problem happens to ive never heard them say that fixed it. Ive always thought it had something to do with oil flow pressure to the oil tank and cooler. Im thinkin theres something blocking or hurting the flow somewhere and the oil pump is building up pressure inside the cases.
markvette
12-26-2003, 04:16 PM
i had thought about using yamabond 4 instead of a base gasket. everyone i now uses that when they put their cases back together. this thing runs great and dont burn oil or smoke, it also has 212 pounps of compression. thanks for the help. now if some one knows exactly why it blows this oil.

Mark
abcracing
12-27-2003, 01:48 PM
markvette i hate to tell ya that when they put ur motor back together i bet $100 that ur center case gasket is blocking the oil passage way in ur cases.its nothing major but it suck cause u have to tear ur whole motor down to fix it.look around the edges of ur side case and i'm sure u'll see a little notch where u can just see a little bit of a gasket.had it happen a few times to me.hope that isn't ur problem because of so much work to get it fix but i bet thats it. later BILL
markvette
12-27-2003, 03:35 PM
where would i look for this on the cases, top, bottom back or front. i almost hope your right, at least i would know what was wrong.

Mark
abcracing
12-27-2003, 03:40 PM
markvette its the oil passage on the top