How damaged does the piston look? Does it need to be replaced?


Would this cylinder head work? It is for an F4i, does that matter?


F4i cylinder head on eBay

 

I cant really tell the damage to the piston from the pic. is the piston cracked? if there are no visible cracks or holes it is probably ok. As for the f4i head, Ive heard its been done, so you could search forum for that. I dont see any cams with that head either.

 

No, the piston's not cracked, it moves smoothly within the cylinder.

Any ideas what may have caused this to happen in the first place? I'd hate to get a new part and then have the new part fail after a week due to the same thing.

Anything else I need to check? Thanks!

 

it would honeslty be more cost effective/better piece of mind to just buy one off a wrecked bike and swap it. the one you have now will need to be torn down and completely gone through to make sure theres no pieces left in it, so youre looking at a complete gasket set, everything basically. new head, timing chain, etc etc. the list would be forever long of tiny things.

 

Swap out the whole engine?

 

what type of oil and what intervals were you running? the only other culprit could be a blockage or pump. I used to remanufacture cylinder heads for a living. that head you have is no good except for scrap metal. you could salvage the valves that arent bent, the lifter buckets and shims, springs that arent broke or weak, retainers and locks, MAYBE the exhaust cam (the bad one was on the intake side right, im too lazy to check the pics again), the sprockets, and i think thats about it. IF you wanted to go the CHEAPEST route you could get another head and see what happens, but I would do a thorough teardown and go over evertything in the block to check for wear and clearances. Also cleaning is your best friend.

 

Do you do wheelies? I still wonder why you only had oil starvation on #1. You could buy another engine out of a wrecked bike, but you still wouldnt know its internal conditions either. If it were me I would either buy a diff engine and hope for the best, or I would buy another head flush the engine to recheck for metal shavings(I know you said you didnt find any before) put it back together. Verify CCT is functioning right. Probably would leave valve cover off( I know its gonna make a mess) to see if its pumping oil to all cylinders. I can't figure the oil pump being bad if the other 3 cylinders were lubing fine. I would bet on a blockage, but the questions is where, in the bad head?

 

there definantly looked like metal shavings to me in the pic of the oil pan. up in the corner.

 

No I don't do wheelies, but I don't know about any owners before me. I bought it used just about 2 weeks ago.

Are the metal shavings from the cylinder head? The cylinder head was pretty messed up.

 

Most likely, but i would go ahead and tear the bottom end down as well. Check the rods, mains, wrist pins etc if you plan to reuse the bottom end. If not go ahead and tear it down anyways just for the fun of it just to see what it looks like. That will give you a clue as to the maintenance thats been done.