Is the timed crankcase breather system a stock DS uses adequate for big bores?

What modifications if any are people using?

Thanks,

Scooby

 

I have to ask what you mean by "timed" crankcase breather?

On my 730 I run the stock crankcase breather to a small K&N, no problems to report. Are you having excessive blow by?

 

I run the breather off the magneto on a hose up over the radiator then down along the base of the frame. I just have it open to atmosphere. It terminates near the end of the plastic engine skid plate.

 

???

 

Good grief I'm slow![img]i/expressions/face-icon-small-blush.gif[/img] I just figured out why you are asking this question[img]i/expressions/face-icon-small-wink.gif[/img]

I think breather capacity has more to do with how much blow-by you have, not displacement.

A 650 that needs rings will need more breather capacity than a new 800..............or a 720 that gets out of round due to insufficient cylinder wall thickness and bracing will require one hell of a breather to keep oil lines from popping off eventually.[img]i/expressions/face-icon-small-wink.gif[/img]

My $0.02

 

I used to run a catch tank LOL now with my hpr cyl I use the stock line with a small k&n filter[img]i/expressions/face-icon-small-happy.gif[/img] no problems with blow by

 

Does any one see a problem with running the crankcase vent tube to the intake tube (between air box and Carb)? Like the stock carburetor slide breather line.

Thanks

 

I run mine there... there is a nub on the opposite side of the balance tube on the intake snorkle. I drilled it and put a brass 90 degree fitting in there. I extended the tube from the case breather all the way back... very clean and absolutly no mess. I set it up this way when I removed the airbox.

 

All of my stock bores blow oil out the vent like crazy. I have had a catch can on all of them, but it still made a mess. So now I just run a line up and over the radiator and back down below the machine.

Our two brand new engines both blow oil out like crazy. I think it has as much to do with the bumps as the blowby. IMO!

 

Could you be over filling your oil tanks?