Hi,

I have a 1986 TRX 250R. It has a Pipe/Silencer, Rad Valve, Reeds, Reed spacer, Powerhead, 38 mm carb and K&N Air Filter.


I had originally jetted it to a 165 main jet and it ran fine for 2 years with this jet, but then seized one day on the road at about 1/2 throttle in 6th gear. I was just cruising on the bike when it happened and not running it hard.


Since I rebuilt it, I've been very concerned about the jetting, so I went up to a 175, then 185 and now a 192 in hopes of finding a jet that would make it sputter. It seems to run fine on all the jets. If doing woods riding, it will load up a little, but by the time it's wound out in 3rd gear, it's cleared itself out and runs fine right up to 6th. When I originally jetted it, a 168 would make it sputter on the top end. I did crank-bearings and seals during the rebuild incase there was an air leak there.


I can't understand how a 168 used to make it sputter and now it burns a 192 fine and there have been no changes. Any thoughts? One other thing, the packing in my Fatboy silencer is completely gone. I doubt this would change the breathing of the motor sufficiently to cause such a change in main jet size.

Any help would be appreciated.

Thanks,

Ken McLaughlin