My 1998 1100RT has developed a curious condition that I'm trying to narrow down. Symptoms...
- Engine misses abruptly; similar to what happens when I hit the rev limiter
- This occurs at 4,000 to 5,000 RPM, under load and full throttle, typically in 2 or 3 gear
- It's one, quick miss, and the engine returns to normal
- The miss is very noticeable; the result is significant enough to unsettle the suspension
- The symptom will occasionally repeat itself in a few seconds if I hold the throttle open, but it is somewhat intermittent
- No change in RPM
- I can't completely rule out some sort of abrupt slip in the drive train, but there is no RPM increase
- Bike has a slow leak into the driveshaft housing from the final drive; approx 15 cc leak in 2,500 miles; not making metal and no side-to-side play in rear wheel
- Bike runs normally under low to moderate load conditions
- No other changes to bike performance - starting, running, etc.
- Bike has 31,000 miles
- At 27,000 miles, spark plugs replaced (Bosch Platinum +4 4418), valves adjusted, throttle body sync
Since the onset is so sudden, I'm thinking this is electrical. I'm a reasonably competent home garage mechanic who performs my own maintenance. My first step is to replace the plugs, then the spark plug wires. I believe the wires are the originals, so they are 18 years old.. After that, I'm looking for suggestions. HES seem to fail around 70,000 miles or so and I'm not aware of these symptoms being associated with the HES.
Thanks for any suggestions you may have.