Hey everybody, This is long winded cause I have a lot to explain, but I’m Having some issues with my 03 R.
I’ve owned it for about 4 years, rebuilt it once about 2 years ago with all the fancy stuff, hot rods balanced crank, hot rods relived rod, kibble white stainless valves and springs, and so on.
Maybe 50 hours since that rebuild, and it was workin great with normal maintenance and whatnot.
When The problem started it was a quick cut out about 40 minutes into a ride. Decided to continue on back to camp, about 3 minutes away, it bogged and sputtered real bad, wouldn’t really run past 1/4 throttle without sputtering and backfiring real bad.
Did as much trouble shooting as I could while out in the desert (checked and cleaned the carb, disconnected tps, disconnected the killswitch, checked the flywheel/stator, tapped the coil/cdi box), and it kept having the same issue.
After about an hour of starting it several times, trying to rev it more than 1/4, shutting it down, and trying to change something, it finally clicked. Loud and fast lol...
Left side crank seal failed, the body of the seal made its way into the timing chain and caused it to jump time.
Tore it down, found the seal, and looked everything over. There was some witness marks where the piston contacted the valves, but they moved smoothly and easily, didn’t look bent, and doing a kind of leak test with some gasoline, the valves still sealed perfectly without any bleed through of gas. So I reused the entire head. Valves and all.
Got one of those wrench rabbit rebuild kits, got everything replaced, buttoned up, and installed back in the frame.
Started up first kick (for once) and idled real smooth (for once) and was real responsive with throttle input.
Well after a few heat cycles, checked the fluids and spark plug, everything looked good so I decided to take it on a ride. About 35 miles, never went over 5/8-3/4 throttle, did a few heat cycles while on the ride.
Got back to the house let it cool for about an hour and a half, went for another couple heat cycles, and the same 1/4 throttle issue started again.
I’ve checked the new left side seal behind the flywheel (previously failed), timing, spark, fuel delivery, throttle cables, and I’m loss as what I should do next. No matter what I do, the same issue with everything.
Any ideas? I can’t figure this out and I’m about ready to throw it in the trash.
Thank you!