Small Breather Pipe?

[MPO]

Does anyone know why we have this small breather pipe that connects to the Trumpet Base?




Cheers

MPO

[MPO]

Sardonicus said:

Yes, it's a vital part of the positive crankcase ventilation system

Sardonicus


Thanks for your reply, it got me researching a little more It seems that the small pipe is to give positive pressure when the engine is idling and the butterfly closed (the larger vent pipe would be inoperative at this time). Makes sense now!

Thanks

MPO

[MPO]

As an update, I purposely blocked this crank case vent system (that would stop the large and small breather pipe operating) last year and tweaked my 14CUX maps accordingly getting the AFR I’m looking for.

I have seen no adverse effects in doing this, no lifting of the oil stick no oil seepage either . So, I will be blocking off both the small and large pipe on a more permanent basis to prevent it entering the combustion chambers and probably effecting performance. Everything will be reversible…

Temporarily, I am venting to the atmosphere with the original flame trap in place and a suitable filter on top. I may add a catch tank this year…

Cheers

MPO