2007 FXSTS
Engine idles fine. But at highway speeds (under load) 55-70mph engine starts cutting out (bucking) it gets real bad if i try to accelarate to make a pass.
Just got out of the shop a week ago for the same issue ran good on receipt. now the issue is back.
Any suggestions would be greatly appreciated.

 

FI or carb. Sounds like the engine is starved for fuel. I would check the simple things first. Clogged or broken fuel line. Petcock broken for carb, fuel pump for FI.

 

Fuel injected

 

Had a similar situation on my '06 Deuce, turned out it was a pinhole leak in the fuel line.

 

There were issues with 2007s and the fuel lines inside the tank. They would rub, get a hole, then starve for fuel, especially when the fuel level gets below the hole. Not an expensive fix.

 

And the )04's. 05's, 06's, 07's and 08's... have the same issue.

Lots of owners with different yr bikes are having same problem. Most are saying the Ethanol is causing the fuel line hose to go soft and the pressure from the fuel pump makes ahole in the like causing the miss issues.

For the OP, the best way to check to see if this is the problem is to fill U tank..

If the problem goes away but returns as Ur fuel level goes down, then it the pinhole in the lines.. Mine start missing about 90 miles after filling up the tank.

Others have reported more miles and some with less before it started missing out.

U need to replace fuel lines in tank and probably might as well put in a new filter also..

its about a 2 - 2 1/2 hr job...

I was away from home on vacation last yr when mine did it. Had to have dealer do it..no tools... total cost +labor was $335.. for everything new..


Also U can check to see if she throwing any codes.. that will also tell Ya.




.

 

I guess ethanol is the latest "boogeyman"?
Fuel system components have been designed with 10% ethanol in mind for at least ten years. Going a step further, people switch over to 85% ethanol (E-85, because it's like race gas) with no fuel system degrading problems.

 

Interesting. I have this same issue on my Deuce and I thought it may be from a bad tune as I have pipes and stuff but I also have a fuel pack with a good map installed. This only happens when I try to get on it on the highway to speed up past 55 if passing. The bike will just buck and act like its trying to die. I will have to replace this stuff and see if that fixes it before I have a shop look at it.