I'd like to know if those of you that have 2001 DS and newer have a problem with excessive oil blow by. This week DemonDS
was over at my home and we were doing a little work on his bike and I noticed that his crank case breather hose was about twice the diameter as mine (2000 DS)- he says he's always wondered what the big deal was all about since he has no oil spillage what soever. It makes sense that with a larger diameter hose that the velocity of air being expelled will be significantly slowed and carry less oil- let me know if this is the case with all 2001 and newer bikes and I'll replace my hose in a heart beat. ( I'm probably gonna do it any way)
thanks

 

Major no spillage here either. I have not looked closely at a pre 2001 ds so I did not know that the line was a bigger diameter. But what you said makes sense to me.

Do you still have your line routed up under the gas tank cover, or is it somewhere else?

Bat

 

If you look carefully at the 2001, the breather actually has a smaller diameter hose inside a larger diameter hose.

If you're having blow-by problems you should perform a cylinder leak down test. Anything more than ~5% could be an indication of worn piston/rings/cylinder, assuming the leakage comes out the breather when running the test.

I had some broken rings on a stock piston. I had blow-by problems. The cylinder leak down was 6-7% (bad). After installing a new piston and rings with a cylinder in good condition the cylinder leak down was 2% and the blow-by problem was gone.

By the way, I noticed that 15W50 or 20W50 oil seemed to have more blow by than 10W40.

 

Scooby-I haven't performed a leak down test but my piston and rings only have about 10 hrs or so on them. I did notice that the first 2 or so inches were about the same diameter as my hose.

Bat - was your breather hose originally located to vent up into the gas tank cover? In the '00 model it ran back into the airbox and made a bit of a mess in there.

 

Sometimes new rings (hard chrome) take a little time to seal. It is important to have a good crosshatch and the least amount of egg and taper
hopefully you made sure it was all good or it might never seal.

 

New engine, old engine, it doesn't matter. I always have blow by with my 2000.

 

vegas650, some people increase clearances for high endurance racing motors. This could explain your blow by. Have you performed a cylinder leakdown test?

 

Major, yes my breather hose went up into the area directly in front of the seat, under the gas tank cover thing and it went into a hole in one of the plastic hoses that connected back into the air box. It was kind of funky.

Anyway, I took those big black hoses off when I went to the carb mount filter and I put a breather filter on the end of that breather hose.

Hope that helps

Bat

 

You can put me in the same class as vegas and i know jeff there with us too!!!!
jeffs being mister big bucks has a awsome system to keep his engine clean me i just cut the hose stuck on a crank case breather it works real well blowby is minn. no problem mine is a 2001 too

 

Any engine is gonna have oil come out the breather. Most have it ducted into the intake for emissions control. Look at a 400EX next time you're around one - they have a plastic cannistor on the breather line.
My '01 DS had the big hose slipped over the smaller hose with the joint siliconed, but this joint leaked. Made a mess under the motor, instead of behind the tank!
I lose only the tiniest amount of oil - I think its vapor condensing on the pleats of the filter - so I wrap it in gauze with a rubber band, and change it every ride. No more mess escaping the filter.