I bought an ex-race bike that I'm currently going through top to bottom. One thing I noticed is that the previous owner had eliminated the crankcase breather hose and simply clamped a cap over the bung on the top of the valve cover. Is this OK or should I try to rig up a crankcase breather filter that just stubs out from the valve cover? There is no airbox lid and it has a DNA filter setup.
Crankcase breather questions
- Thread starter TT2
- Start date
1JZSupra
Active Member
You should not have that capped off. Does your air box not have the hose ports? Have a closer look.
Thanks. Just took a second look. The airbox does have the port with a short piece of hose attached with a plug in the end. I suppose the builder thought that this would keep the intake air temp lower. He failed to compensate for venting the crankcase though. I'll look for an appropriate breather filter.
1JZSupra
Active Member
I have an oil catch can on mine.
B7ACKTHORN
Member
Capping it off is a bad idea as it will cause excess pressure build up inside the engine. Either it's vented or vented positively or as 1JZS said, using a catch can works best if all three is a menace. With the treehugging policy taking hold, race bikes are waived off from this, but if you're a law abiding citizen, it's better to vent it safely than not to vent it at all with the predicament of a low engine life.
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