Supercharged bike blowing oil cap off

[Justin Lakes]

We keep losing oil cap/dip stick off. I'm thinking it's under hard acceleration. Is anyone else having this issue?
Is there a way to remedy it ? Venting crankcase to exhaust or better venting in general.

 

[Tripps]

I think @Claviger was doing some experimenting with that, but I don't remember the details.

 

[WyldCFH]

@warp9.9 & @R-III-R Turbo may be able to assist. Both have forced air bikes.

 

[warp9.9]

We keep losing oil cap/dip stick off. I'm thinking it's under hard acceleration. Is anyone else having this issue?
Is there a way to remedy it ? Venting crankcase to exhaust or better venting in general.

You are suffering from the detorats!!!! Check your rear crank case vent your probably blowing oil out it too.
Easily fixed by changing out the bad piston or pistons. That's where your boost is going by and pressurizing the lower crank case!!!! You can scope the pistons to verify or run a compression test. In the picture below the almost white section on the pison edge is the top compression ring.

The only other thing it could be is your rear crank case vent is soaked with oil to the pressure blows the oil cap off. I suggest you try the scope or at least a compression check when you do the compression test make surre all the plugs in the other two cylinders are out.

 

[Jvheli]

Sounds exactly like this bike. Sorry dude, but I think Scott is right. Compression test will tell. See the end of the attached video.


https://youtu.be/HnKBdkwOFhg

 

[R-III-R Turbo]

As above, possibly blocked breather but more likely blow-by past your pistons. Do comp test and go from there...

re claviger iirc he was trying to make a slight vacuum in his NA motor crankcase by using the exhaust for a venturi, like exhaust scavenging only this would be crankcase scavenging, to lower wind resistance on the pistons coming down.
I wouldn't try it in this case.

 

[warp9.9]

As above, possibly blocked breather but more likely blow-by past your pistons. Do comp test and go from there...

re claviger iirc he was trying to make a slight vacuum in his NA motor crankcase by using the exhaust for a venturi, like exhaust scavenging only this would be crankcase scavenging, to lower wind resistance on the pistons coming down.
I wouldn't try it in this case.

I did something like that but run it thru a baffled oil cat can with a tell tail on it. But before you freak out check the crank case vent first. I have noticed some of the oil caps come out easier then others. Maybe yours is a loose one ?

 

[Tal]

My thinking is the pressure being built is from a blockage or resistance from the breather.while it's a difficult thing to get at, you need to get at the crankcase filter and maybe run a hose from there to a filter...makes for better maintenance.
If the filter is junked up the oil filler cap will pop....a bit like holding your nose and blowing...your ears pop...

 

[TURBO200R4]

a bit like holding your nose and blowing...your ears pop...

i have an image in my head can u post a picture

 

[Jvheli]

If needed, I have a set of used pistons with rings.....not trying to be a glass half empty guy here. Free if ya need em!