Not being adequately familiar with RS125r NF4 engines is it possible to do parts upgrades to NX4 topend bits which seem far more widely available out there? (As in same cases and crank specs) Thanks for possible info.
Not really. You can change to the NX4 pistons if you make some changes to the crank when rebuilding it and then get the barrel modified. Is it worth it?? Probably not. Put your money into suspension and extra exhaust pipes as the originals break up after decades of use. parillaguy
So far none of the usual suspects even offer NF4 piston kits. So I'm looking for a workaround. Thanks, BTW! F
wossner have NF4 piston kit. http://www.wossnerpistons.com/produ...name/wossner-piston-honda-rs125-53-98-mm-bore 14mm piston pin (NX4 have 15mm piston pin) you can have NF4 crank rebuilt with a CR125 1988 rod kit or use the nx4 rod kit and piston, but you need to lower the cylinder by 1mm(like parillaguy said)
Learn from my mistakes. Just say no to wossner. I am not alone. Google it before you make a decision.
I bought a pair of Vertex piston kits which I trust from my own KTM experience. Not sure if lowering an NF4 cylinder affects port timing or flow but for now staying OEM spec works for my purposes. Down the road and for others the availability of NF4 parts is an issue. I suspect there are some options out there. ...Thanks!
