Hi all,

I'd first like to thank everyone for the incredible resource and help this site has been over the past couple years, but I've come upon a problem I just can't figure out. Hopefully I don't get too long winded, but I want to describe things the best I can.

Starting about a month back I noticed my bike would "hesitate" or "stutter" cruising down the highway at 80 or so. It would also backfire a bit as it stuttered. I was on a long trip and checked fluids, etc. when I filled up next and everything seemed good. So I sort of chalked it up to bad gas. The problem went away for a bit and then appeared again every once and awhile, usually only while cruising 65 - 70 or so down the highway. Never an issue just cruising around town. Now this past weekend it started this again, but much more often and at various times. Yesterday it was doing it quite a bit. Usually when on the throttle. It seems to happen more in the upper rpm's. I don't have a tach so I'm not sure exactly where. I continued driving home at 60 and for the most part it was good, but would still hesitate now and then. Often times taking off it seemed ok until I really got on the gas. Then it would stutter and backfire, but continue to keep moving down the road. Now when idling in the garage the motor seems louder, but that could be my head playing tricks with me.

To me it seems like a fuel problem (running too lean?), but what do I know?

Details of the bike are... 2004 Fatboy, K&N filter, D&D Fatcat exhaust, power commander III usb. Other than that it is pretty much stock.

Before I take it in the shop I'd like to have an idea of what it might be. Any thoughts or suggestions on what to check would be greatly appreciated. I'm not a mechanic obviously, but I can handle some of the simplier task.

Any ideas? If you need more info, don't hesitate to ask. Thanks in advance!

 

My guess would be misfires. Check your spark plugs. If there's a glassy deposit then that melts at high temperatures and shorts out the electrodes.

 

Pulled plugs today and they looked good. Cleaned them up a tad and took it out for a ride. After about 15 minutes (as usual) the problem reappeared.

 

Before you dig into it, spend $10 and run some techron or redline s-1 fuel system cleaner through it. 2-3 oz per tank of fuel. You could have a sticky injector. I run it 1-2 times a year in everything I own. The redline s-1 is the best as it is really all gasoline detergent and has no oil in it. You can get it at www.myoilshop.com you will find techron at autozone or AAP. BTW, the cleaners will degrade a little performance while cleaning.

 

Since it is only happening at High RPMS you may have a clogging fuel filter. To change this you need to open up the tank and get to the fuel pump. Some people say change the fuel pump to because that could cause the same problem. Might as well do both while you are in there.