Greetings, I have a 94 FXR 80" Evo that is stock. The bike ran fine for 9 years until a squeal on the right side of the motor got louder till the sound was unbearable. A HD dealership indicated this could have been the oil pump going. At about 73,000 miles I had the motor sent out from the HD dealer for a Harley rebuild of the motor.
The bike runs fine... when the temperature is under 80 degrees F. Above 80 degrees it starts to buck, back-fire, and run very rough. I took it back to the dealer multiple times with no resolution. Humid or dry air does not affect the bike... only when the temperature is above 80 degrees. Any ideas? Thank you, STLCHUCK

 

Was the ignition system (top to bottom, not just the module) refreshed when it was rebuilt?

 

A slightly rich running motor on cooler days will run awesome but on hotter days it could reek havoc. What do the plugs look like on the hot days?

 

I'm not aware if the ignition was rebuilt. I have not checked the plugs on hot days. I can barely make it back home with the back-firing and lack of power. I did have the tank refinished. They replaced the inner liner and petcock... three times. When I first rode the bike, it had no power... almost like the carburetor pump was not working. Subsequent trips to the dealer resulted in marginal improvements... until it got hot out. The mechanic indicated they were "messing" with the timing. Thanks, Chuck

 

check the sensor in the nosecone. you can test it with a heatgun when its working fine to make it hot and fail and a can of compressed air to make it cold when its not to see if it runs fine when cool.

as far as the squeel, i assume that part was fixed and its not still doing it correct?

 

Greetings,

I used a hair dryer on the ignition sensor cone. When it got hot enough the engine immediately back-fired and died. I replaced the sensor with one I purchased from Harley. I marked where the old sensor was positioned and installed the new one in the same position. I had to use the old male connector swapping the three wires. I did check the pick-up cup to make sure it was seated in the correct spot (it was).

The bike runs fine although I will most likely have to wait till next year for warmer temps for a hot riding test. I tried timing the bike with one of my old style timing lights; the light worked but I couldn't see the timing mark through the view hole. I have an old auto tester for the RPM but it did not pick up any signal.

Thanks for all the advice. Best regards, STLCHUCK

 

That mark is almost impossible to see unless you paint it with a bright color.
I use white Testers paint to color that mark when I'm timing a bike.

 

I've been using typewriter white out for a real long time. It has that little brush so you can paint that mark. Works good.

 

Yeah that stuff works good I ran out and my son does models so I switched to testors.