Hiya does anyone have any information about doing a 660 conversion with a 3he bottem end and a 4jh (foxeye) top end ?

Reason for the 3he bottom end is so that the chain alignment on my 3he is back to were it should be

I haven't heard of it done, but you need to make sure the oil and water galleries line up. The 3he has a longer stroke than the 4JH soyou need to check the piston doesn't come up higher than the original other wise you may have the valves hitting it. Likewise if the piston is to low you'll loose compression.

You need
3HE crank
3HE or 4JH cases (4JH cases need custom oil seals for the crank, and you have to use the 3HE pickup)
4JH barrel, pstons and head
and then ether
3HE conrods bored out by 1mm (or FZS600 conrods, whch are the same length as 3HE rods, but have the wrst pn diameter of 4JH ones)
OR
a base gasket spacer plate the depth of the increased throw (2.6mm?) and adjustable cam gears.

I'm starting one myself, try FZRonline, plenty of information there

I used to use FZRonline.com until i cam across this site as have found the information on this site even tho its about 400's that i had been looking for a few months


Big problem with FZRonline.com is its mainly americans and they didnt have the later fzr6 (4jh)