My '02 FLSTC was running great until a couple of weeks ago. The bike would generally run well up to highway speeds, but somewhere around 60-70, it would start to sputter, backfire, and lose power--not every time, just sometimes. The dealer replaced the crank position sensor, and the bike ran well--for a couple days. Then the problem reared its ugly head again.

I made an appointment to have the dealer look at it again, and the bike sat for about 36 hours. I took off to take it to the dealer, and for the first time, the bike started acting up at slower speeds. I didn't even make it out of third gear, not even warmed up, and it started up again. Even so, I somehow managed to ride it the whole 20 miles to the dealer without having to get it towed. That was yesterday morning--the Fourth of July. Obviously they didn't look at the bike until today.

Well, guess what? (You probably see this coming already!) The dealer can't get it to act up. One of the mechanics and then the service manager both rode it, and it ran just fine for them. Don't you just hate intermittent problems?!!

The symptoms seem to scream "crank position sensor," but that's what they replaced only a few days ago. Obviously it's possible (but unlikely) that the part was bad out of the box or has gone bad prematurely, but what else could it be?

Help! Any ideas?

 

Is this a carbed bike? Could you have gotten some bad gas or has she been sitting a bit with ethanol fuel in her?

 

Is the bike EFI? Pin hole leaks in the in tank fuel line.

 

Dont mess with Sasquatch

 

Oh, yeah, I forgot that some '02 models have EFI, but not mine. It has a carburetor and, of course, NOT a fuel pump.

The bike hasn't been sitting; in fact, up until the problem arose, I'd been riding it virtually every day. In two months, from late-April to late-June, I put about 4K miles on it. I don't think I got any bad gas, but I suppose that's always a possibility.

 

If you can do the work yourself, start with the simplest, cheapest possibilities.

Pull the carb, disassemble it and use compressed air to blow out the passages and jets thoroughly.
Check the vacuum piston to make sure there are no holes or leaks.
Do the same with the accelerator pump.
Check the float level to make sure it hasn't drooped, running your engine out of fuel.

Next thing is to replace the intake manifold gaskets.
These are less than $10 but are alot of work to change bit it's worth the cost and effort.
Getting the bolts out of these gasket flanges requires a short reach, or ball style allen wrench.

 

is the bike putting out any codes?......

 

Does the same situation occur at the same RPM but a different gear?
Reason:
Trying to figure if electrical as in crank or cam position sensor or coil.
If fuel related then it should occur at same RPM but different gear since consumption should be about the same.

 

Im with the guy check your intake gaskets with a little wd 40 or carb cleaner check them when cold and when warmed up if your bike races up that is the problem. Alot of intake seals are going in this heat. I just had to replace mine.

 

Sorry, guys, life got crazy for a while, and I never had a chance to get back here and give you the scoop. Long story short, it turned out to be the fuel supply valve. The bike is running great again. Thanks for your input!