Hi last one I built I used 520 but I wish I stuck to the smaller chain as you don't need to remove any casing material when you reduce front sprocket size
its also much lighter and plenty strong enough to cope with the c15s power.
Hi as I understand it you will need to use the b25 head otherwise you will have problems around the push rod tube,this will also mean the use of a b25 piston to suit the combustion chamber, I assume that you are already aware of the need for a quarter inch
spacer at the base as the c15 conrod is longer.
good luck
hi GUYS i am at my wits end with my b25,i have now re built it for the second time,starts fine runs sweet and then as it warms up Awfull big end clatter.
Theres good oil return to the tank.
If i let it cool for a while it starts sweet again and then this orrible noise.
Any ideas or should i set light to it.