A budy of mine endoed his f4i last night doing a stoppie. it was perfectly upside down for 2 minutes or so. (resting on the handlebars and seat)

now it wont start. the fuel pump primes, so i don't think it is the tip over switch, or BAS. we tried to start it, won't turn over. tried push starting it, locked the wheel in every gear.

the compression is super high, like 300!!

any ideas?

 

any ideas? Not trying to be an a** or anthing, but try to stop doing all those stunts for your bike. Their made to ride. Thats why insurance rates are so high these day.

 

yeah, ok. it is a stunt bike. not street legal. its not mine, it s a friends. it was in a closed parking lot. no cars, no people.

ok?

 

that actually doesn't answer the question either.

 

I'm going to guess that since the bike was directly upside down for a while oil bypassed the rings and coated the upper cylinder walls, hence the ridiculously high compression.

I suggest removing the plugs stuff the holes with papertoweland turning the motor over a whole bunch.

All just a guess though....

 

it sat for 20+ hours, still won't turn over. is it possible the oil is still above the pistons?

 

Yep.

If the thing was upside down for a couple of minutes while the oil was hot then oil got to the top end. Even if the oil was cold it'd still pass thru the piston rings albeit not as much due to viscosity. Ifthe oil bypassed the rings the oil's still going to do its job and coat the metals regardless of where it is.

Furthermore, if that is the case and oil is in the top end, then chances are your plugs are toast as well.

Pull plugs, stuff papertowel, crank motor, check papertowel for oil.

 

oil will shoot out when you turn the motor with plugs open.

 

yep, your bike needs to puke....pull plugs crank repeat

 

lol, never heard it called that before..

but yeah, it does. The oil prob. won't naturally come down past the rings back into the case.