today when we went riding my buddys ds just started to blow oil out of the vent filter and i mean alot of oil!! covered the carb cylinder and exhaust. is this a seal that blew?? or rings bad?? what is it?? thanks....

 

presuming you havent just filled it up with several pints too much oil, im afraid to say it sound like a cracked or stuck ring since it hapend all at once and not gradualy.

i would check the oil level thing first then try a compression check, if you dont have a tester just check for the amount of air flow from the vent when running shouldnt be that much most motors sort of pulse as they suck and blow on alternate strokes of the piston.

A comp tester is a fairly cheap piece of kit just make sure you get one with a 12mm adapter for the plug hole on the DS.

 

just had a thought about the dry sump system on these motors, maybe that could cause a problem if it wasnt returning the oil to the tank fast enough, just thinking out loud maybe some one else can help out

 

it has brand new rings. maybe 18 hours on them.

 

Has it been blowing oil since the rings went in , or has it just started on the last ride?

 

no it was doing it before but not as bad. so we put new rings in it. after that it sill did it but not alot. until today it just blew up and was dumping oil everywhere. isnt there a seal for this but you have to split the case right? oh i better throw this in, the ds is undefeted at genoa!!hehehe... we started to run with the drag banshees. there was a yfz with a full stage 3 with a 120 rider. got him... and of course i couldnt beat the drag banshees[img]i/expressions/face-icon-small-wink.gif[/img]. sorry had to throw that in..LOL..

 

if oil is blowing out of the crank case breather the pressure can only come from the cylinder and there is no seal between the two the rings are all that keep the combustion pressure in the cylinder and out of the cranck case.

I would definetly go fro a comp check to see where your at, I have never had the DS motor apart so im not sure of the ring configuration in them, some motors have rings that have a leading edge and can only be put in one way etc,
Was the ring end gap to within tolerance when you measured up the new ones in the bore. also was the bore still in good shape was the cross hatching still visible.

Try starting the motor with your thumb over the end of the hose if its blowing air like its an air line it will need stripped down, It sounds horribly like you have cracked a ring while drag racing, but at least you were winning, every silver lining has a cloud

 

its not my bike....and yes we did a comp test came back perfect.

 

when the bike is running do you have oil flowing back to the oil reservoir?

 

geez i hope so but will check. 3/8 line right? on the left side bottom. its so weird it did it before rings and now after new rings.