Hitchcocks Forum

I've just rebuilt my tuned classic/kiskstart Bullet (after blowing it up on the Santa Pod dragstrip several years ago) and it's running really well apart from one problem.

The brand-new latest type crankcases I bought have a different breather system to the traditional Bullet's crankcase breather located on the upper left side, and I'm still puzzled how it is supposed to work - I think the crankcase must have an internal vent directly into the oil tank? One breather from the upper timing cover is working fine with just the supplied pipem and a duckbill. However, the main breather comes directly out of the top of the oil tank, and this is currently pumping out oil at the rate of 100 ml in 10 miles - which is rather excessive! I hope it's meant to have some sort of one-way valve instead of just the pipe and duckbill I've fitted - can anyone with a later type engine enlighten me, please?

(I was previously using the excellent Hitchcock's breather conversiion, but it can't be used with these later type crankcases.)

Martin,the breather system for your new motor uses a breather box assembly,see under Parts book online,model 65.
The tube at the timing side is actually a return for excess oil.The breather box??has a duckbill inside.
Works satisfactorily if the rings are sealing proper,otherwise this system can give heaps of trouble.
Jack
ps hadn't heard of the blowup but remember the 612 at the drags.

Have a look here http://www.whfolk.co.uk/REOCHUMBER/Arti ... eather.htm

Hi Martin If you haven't put the engine together, you could seal the crankcase hole with "J-B WELD" resin and with a small amount of drilling and tapping, re-install the left hand side crankcase-neck breather fitting so you could fit a breather tube with Duck-Bill valve.