Crankcase vent issue

[racepaul1]

Looking for some input on a problem I am having. I am currently racing a 78 GS1000E, the motor was recently rebuilt with a 1025cc kit and I added CR33 smoothbore carbs. This past weekend the was the first time on track with this set up and it started puking oil from the crankcase vent hose, a lot of oil.  This only seems to happen on or about the second lap and definitely happening  on the long bank right hand turned which wide open top gear. We have done a leak down test and a compression test and both are fine, oil level is fine and the carbs are leaking fuel. if it matters I am running Motul non synthetic 5100. Any help is greatly appreciated.

Paul

[gs7_11]

Are you talking about a crankcase vent fitted to the oil filler hole?

[Simbec1863]

Any pictures of the set-up??

[Guest YoshiJohnny]

9 hours ago, racepaul1 said:

Looking for some input on a problem I am having. I am currently racing a 78 GS1000E, the motor was recently rebuilt with a 1025cc kit and I added CR33 smoothbore carbs. This past weekend the was the first time on track with this set up and it started puking oil from the crankcase vent hose, a lot of oil.  This only seems to happen on or about the second lap and definitely happening  on the long bank right hand turned which wide open top gear. We have done a leak down test and a compression test and both are fine, oil level is fine and the carbs are leaking fuel. if it matters I am running Motul non synthetic 5100. Any help is greatly appreciated.

Paul

The standard one on top of the rocker cover?

If you haven't added another to the oil filler cap hole then racing will pump the crankcases and oil will find its way out... add a breather.. AN8 fitting, oil filler adaptor and a bit of hose into a catch bottle