Supercharged bike blowing oil cap off

[Justin Lakes]

Ruzz and Warp know.... A comp test may not be conclusive. If your rings are cracked up you may still get near stock compression readings, but have massive blowby when you have boost. If your comp test is ok, rig up a container which can both breath and catch fluid to your rear engine breather, tape the oil cap in place, and go for a short ride, give it the berries and check results. Assuming it is a TTS kit you may have up to 18psi boost. Much more than advertised. I have recorded this on several occasions. If you need pistons etc Jvheli has made an offer. If you have got it apart an want to make it go properly, you can add at least 50hp JUST by fitting cams with timing to suit forced induction and a re tune obviously. I also have some forged turbo/s/charged pistons here still. Going covid-19 cheap. Our $ is worth SFA.... Good luck.

Thanks I'll check into it.. it may be a bit before I start tearing into it.

 

[Justin Lakes]

Could take an old plug, solder or braze air chuck and hose and pressure cyls. with air and listen for leakage. Try and get piston on top and valves closed.

Crankcase pressurisation could also be leaking head gasket under pressure from high throttle openings. Is it blowing coolant as well???

How much boost are you running?

Probably 18ish

 

[ruzzle]

Coolant?

 

[Neville Lush]

Probably 18ish

" probably" ...... measure is good. What is your rev limit set at??

 

[Torque addict]

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

That's my video and my Rocket. Broken piston lands was the culprit. Your crankcase is most likely getting over pressurized by excessive blow by in one or more cylinders. Another vote for compression test here.

 

[Torque addict]

Just to be clear, I should add that after replacing the piston (all 3 actually) I've never lost another dipstick again.

 

[Rocket Scientist]

Are you opening the throttle fully when checking compression ? Makes a big difference.

 

[jlmealer]

My bike froze in my garage (I assume) and it pushed about a half guart of oil out of the engine. I haven't gotten into it yet because I have a car engine torn down, but does this sound like maybe water leaked into the bike's oil and froze? Again, it happened after a sub zero night in this rented house with an unheated, non insulated garage.

 

[Gerald]

My bike froze in my garage (I assume) and it pushed about a half guart of oil out of the engine. I haven't gotten into it yet because I have a car engine torn down, but does this sound like maybe water leaked into the bike's oil and froze? Again, it happened after a sub zero night in this rented house with an unheated, non insulated garage.

What does bike froze mean, no antifreeze?

 

[Gregger]

Need some info otherwise all you will receive are a bunch of guesses....

What do you mean by froze? Is there anti freeze in the engine or just water?? Is the engine stock? If not what mods have been done??? Does the bike have any other issues when running at normal temps. When did it spit the oil out, after a hard run hot, cold??? Did the oil come out of the dipstick or oil cap? Is there any discolouration of the coolant or engine oil?