I have an 03 GP800R that I rebuilt a couple of years back after an oil line came off. Thanks to the help of everyone here, I did all the work myself and it has been running strong ever since. I recently took it out for the first time this year, and it was running great. But late in the day I noticed it felt like it would momentarily lose power at speed, then come back, then pose power, cycling back and forth. I took it home and did a compression check, and it was perfect (same as it has been since the rebuild). So I was suspecting something with the power valves or carbs. This morning I went out riding to do some troubleshooting. At first it was doing the same thing. It pulled hard until it got to about 6000 RPM, then felt like it would if I let off the gas just a little, dropping down to about 4600 RPM, then accelerating back to about 6000, and cycling back and forth like that. I was wondering if the power valves were cycling right, so I took the seat off and rode so I could see the valves. Wouldn't you know it, but the problem went away. Rode strong for quite a while. Later in the morning it had the issue again, so again I took the seat off. Again the problem stopped.

What I could see while riding with the seat off is that the power valves open above 6000 RPM (is that the expected RPM?), and close when dropping below 6000. I tried unplugging the connector to the power valve servo motor, and it maxed out at about 6200 RPM. My suspicion is that something electrical is happening intermittently causing the power valves to open as expected, then close right away, and when they close I lose some power. Any other ideas or thoughts on how I can troubleshoot? For the most part it runs great, and I don't think this problem will cause any harm to the engine. My suspicion is something electrical got wet causing an intermittent issue. Maybe it will dry out and be fine. Or maybe the intermittent problem will get worse until it is bad enough that I can find the issue. Any thoughts would be appreciated.