I would like to hear from anyone running a Pilot cylinder on a TRX250R or any other similar type of swap.

If the bolt pattern was not the same, how was that handled (welding, adapter plate, ...). If the wrist pin was not the same size, what was done there (custom rod, spacers,...).

I have a CR500 top end that I want to put on an FL350R bottom end. This has been done before, but I can't find any information. I know of a few places that put CR500 jugs on Pilots (FL400R), but not a 350. Jay at ATV Racing gave me a price on doing it. I bought the CR parts and then he backed out of doing it.

The FL350 rod is the same as an '86 TRX250R. I can use the newer long rod to gain 4.7mm and not have to shave off as much on the bottom of the cylinder. Most if not all will come off the top.

The bolt pattern is the same front to back but 10mm wider, 5mm on each stud. An adapter plate does not seem to be an option because the patterns are too close. I don't like the idea of welding on cast aluminum which is common for the FL400 mod. It looks like I may be able to redrill the holes in the cylinder and use socket head bolts with offset washers.

The wrist pin is smaller than the 500. I can make aluminum sleeves with a lip on the one end that would fit in the 500 piston and over the 350 pin.

 

the best thing i can tell you is to call FTZ They do the pilot 400 engine on to a 250r at FTZ.