- Sep 4, 2008
What would be the best crank case breather set-up (with part#s please) to achieve a vacuum in the crank case?
PJL said:Or, alternatively, a Ducati Paso breather valve, which contains a pair of reeds...
http://i476.photobucket.com/albums/rr12 ... 1239550036
http://i476.photobucket.com/albums/rr12 ... 1239550247
kommando said:If you have a checkvalve that lets the pressure out but not back in then after the downstroke when the pressure is released, the upstroke will then reduce the internal pressure as the air cannot return back down the breather. The lower internal pressure will tend to suck oil back in instead of excess pressure forcing it out. The check valve has to cope with up to 7000 rpm changes in internal volume so a reed valve copes better than a spring loaded seat.
PJL said:I got the valve for a few pounds off eBay, second hand. Then found some used hoses at a Ducati dealer nearby. The reeds inside are just like those you show.
There are some very nice machined from billet reed housings for later Ducatis, but they are expensive. They are also screwed into the crankcases so are not too suitable for the Norton (though they would be neat). The one I have is off a 906 Paso.
When I visited Pete Lovell in Smethwick (B'ham UK) last summer he showed me a very nice inline reed unit he was manufacturing for British twins, including the Commando. Perhaps give him a call?
Jeandr said:Thanks Phil,
I will look into it, either th Ducati side or making my own. I stopped by a scooter shop ( http://www.scootart.com/ ) yesterday and the owner gave me a kevlar reed, making my own housing should not impossible and I may just put it on the back of the timing chest instead of modifying the crankcase like CNW does.
chris plant said:hi jean, keep us informed, the back of the timing chest seems a better idea than the back of the crankcase,(utiliseing the timing chest volume)