So i picked up an 01 F4i. It was setup for track except wiring harness still there.
I bought it from a dud who told me he hadnt run it himself but bought it as part of a package deal with two other bikes. Looked pretty clean and he ven delivered it to me after i paid him. I got a ton of extra parts and plastics so it was a no-brainer. He had told me that the bike runs but smokes a little but the battery was dead so i took his word for it. So i get the bike home. Charge the battery and got her started. And indeed, just as he said, she was blowing some smoke. But sounded strong. I came to the garage maybe once a week since then and started it and let it run for a few. Until one day she wouldnt start and was floding out. I pulled the vacuum line off the FPR and fuel was pouring. Ok. No biggie i get a new FPR and install it. She fired right up. I still had the top of the airbox off while it was running. Then after about 30 secs it started spewing colant from the vent tube that comes from the top of the valve cover into the airbox. So i shutit quick. Dropped the oil and. As u can guess. All my coolant in my oil pan. My question is what are all possible causes of coolant and oil mixing. I wanna narrow it down before i pull the head off. I don mind doing a gasket i just dont want to do it for nothing. I appreciate any input!!!!! Thanks

 

only really 2 ways blown headgasket or cracked head block.you can do a leak down test to determine the extent of the damage before tearing it down.i would also do a compression test before anything . im not quite a motorcycle mechanic but i work on cars all day and theres only 2 ways.i think maybe the oil cooler on the oil filter could cause this but idnk its possible on cars with coolant oil coolers like these bikes have.maybe someone else will chime in

 

the bike has an oil cooler but i have no idea where the water runs through the engine, or if water cools it there.
i never delt with it but check where your oil filter is when its off maybe you can see the water lines
im guessing you probably are leaking water after you pressurized it into the cylinders, and normally had a leaky gasket

 

there are coolant hoses that run to the oil filter housing one could do a cooling system pressure test and take the oil filter off and see.also if you pressurize the system you may be able to take off valve cover and hear the pressure leaking.they sell leak down tests in harbor freight to pressurize the system and pin point the problem.id start with this and a compression test let us know ..

 

Well i had a friend come over and take a quick look. He told me that its quite common that the water pump impellar seal goes. So i took the water pump apart and its pretty grimy. And the impellar seems like its not spinning freely. I have a spare motor in the garage i got with the bike. Its an f4 motor though so its good for some parts as far as covers and stuff. Looks like th pumps are the same except for the pump cover has an extra hose. I think i will try and swap the pumps first and see if that does it. If not, i will be pulling a motor!! The water pump slides into the oil pan and is driven by the oil pump. I think its worth a try. I will let u guys know. Thanks for the input!!

 

sounds like a winner maybe you learn something everyday,Though im partly skeptical about a water pump leak causing oil coolant to mix.for your sake i hope so,but you could put your head and electronics on the f4 block so youre good to go with a little work anyways!!

 

So i got lucky. Problem was the water pump. I pulled the pump off the f4 motor and swapped it. The cover with the hoses wasnt the same but the pump itself matched up. Trying to iron out some idling issues but other than that she runs good. I wanna thank you guys for your help and im going to post pics of before and after. Track F4i to stunt f4i.

 

Head gasket, oil cooler, water pump, or possibly a cracked head

 

That ^.