does anyone know if an F4 not F4i motor will fit on an f3 frame with the f3 fairings?

 

Neither can! f4 ,f4i motors have the swingarm bolted to the back of the motor.f3 have a separate swingarm and motor.

 

Not a direct swap no, i think the guy i saw do it said it was to wide in places, he had to chop and reweld the frame, the swingarm shouldnt be a problem as it goes threw the frame and the motor, i've fitted a F4 swingarm to a F3 and if it does have bits that get in the way you could just angle grind them off the motor as there just extrra bits of metal, not filled with anything.

 

thanks guys i knew about the swing arm bolting through the motor situation i just didnt know if the farings would work and if all the rest of the mounts would line up i decided im going to rebuild my f3 motor being i got it split in half yesterday the crank bearings are gone

 

if you are doing an engine rebuild, INVESTIGATE EVERYTHING! bearing caps can be expensive and i have seen people split cases and replace bearings on a bunk motor only to have to tear it all back apart later and repair another issue. also, get really good with a plastigauge. i cannot overstate this enough. these engines reve to 13,500 rpms, and the last thing you want is to get a spun bearing because of clearance issues.

 

I would try a rebuild. Unless you have access to a free f4 motor and free access to a good shop I would think you'd be cheaper to buy an F4 in good running condition than to try to shoehorn it into a f3 frame. I love to do mods, but some of the things I see people do just seems impractical and expensive. I feel like this would be one of those occasions seeing as you can buy a good f4 from $2000(if patient) to $3500. I'm all about being patient, I bought my bike in running condition for 400 bucks.

 

(BIG BUGEYES)

WOW!!

(find me one)

 

I am having a F2 spec motor built, my mechanic/machinist said it vital to replace valve seals when cracking open the motor. He said any motor over 10 years old is a must. They get dried out and fall apart when rolling them with your fingers. Even if the miles are low on the motor, doesn't mean the motor was started regularly to move around fluids properly.
If you are replacing bearings, replace the seals too.

 

I posted a pic of an F2/3>F4i swap awhile back. Was kinda ghetto, Have no idea what happend to the pic tho. I have a spare frame that I considered doing this to considering I can find F4i parts/motors for the cheapo