Running rough in 5th gear

[fwbpastor]

I need some help.
I bought a 2002 Voyager XII 2with 37000 miles. Before I even put it on the road, I changed the oil, final gear oil, new tires, new spark plugs, new air filter, new oil filter, new fuel filter.

It has been running great, a real smooth bike. I have put about 1000 miles on it since I bought it. I was amazed when I was getting 50.3 mpg.
I have been using seafoam in the gas tank

Well yesterday, after riding about 150 miles, it started to miss in 5th gear (around 2500 rpm). It felt like it wasn’t firing on all 4 cylinders, either not firing or starving for fuel (I had over ½ tank of gas left). I down shifted and it picked right up again running smooth with no miss.
We had to cross a ferry, so it was off for about 30 minutes, and after we got off it ran good and smooth again in 5th gear for about 30 miles and then started doing the same thing, running rough.

Any advice?

Thank you,
Melvin Haas
fwbpastor@gmail.com
Blounts Creek, NC

[JHD]

The thing that is weird is that your saying it only runs rough when in 5th gear @ 2500 rpm. Does it run rough in any other gear at the same rpm?

[mountainman]

I'm curious if its a voltage problem. Check your alternator output, if ok check connectors and line voltage to ignition for proper power to ignition system. Because if your only missing if 5th gear low rpms that tells me weak ignition source.

[JimK]

You stated after it came off the ferry it ran ok for a while. So it runs rough in 5th after it warms up, that would lead me to think it might be a coil breaking down due to the heat. The heat is going to increase the resistance in the coil and in 5th gear you have more of a load on the engine. Don't know for sure but might be a place to check.