03 XB9R - Fuel Pump or Clutch

[bottlefedbuell]

My Basketcase Bolt with 10K miles has recently developed a Real Bad Backfire/Surge at about 4500RPM.

Cruising at 4500 or so, it will suddenly and violently do a quick engine brake and the tach will jump up about 800rpm or so give a quick backfire and resume like normal. The first couple times i almost went over the handlebars.

Thought maybe the clutch was slipping, so i adjusted it multiple times trying to see if that was the case.
At lunch, i went out in the lot w/o my helmet and tried to see if it was better.
My pump has become real loud, to almost a squelling noise.
If the pump is having problems keeping up, will it lean out and cause the RPMs to surge ?

Its really hard to tell where the problem lies.
Newer battery, all grounds are good, and no codes.
Have not had a chance to data log it yet, afraid it will leave me stranded again.

Anyone ever have this happen?
Searched through the forums and found some cross referance to Walbro pump for Mustang V6, but others say it is not compatible.

Thanks for the help

[OldGeezer]

Hey Bottlefedbuell,

I'm just learning about Buell's myself, and you may already have solved your problem, but I do know a bit about motors and it sounds to me as though you've got either an ecm or a fuel pump problem.

The fact that this happens at higher rpm points more to a fuel pump issue than an ecm issue. I would bet that the problem gets worse if you try to increase the rpm. The squealing noise also points to the fuel pump.

If the pump cuts in & out quickly you'll get the sudden engine braking effect followed by a sudden return of power as it cuts back in. The ecm probably contributes to the problem as it senses changes and tries to compensate for changes in mixture etc...

Hope you get it sorted OK
G

[njdevils1990]

Have you ever ran out of gas? If so it can cause the pump to overheat and shorten the life of its self. But from what you have described it sounds like a fuel pump.
03-07 Buell fuel pump from ASB

[bottlefedbuell]

Well i have never ran it out, and always try to pace my mileage to fill up before light comes on. But i am 3rd owner and first 2 were NOT very nice to this machine. Have fixed many of problems from lack of care by previous owners. Pulled pump and checked for 'chaffed' wires, also replaced sock while in there. Unfortunately, could not find a definate answer on if the 'Mustang-Walbro pump' would work as a replacement. Only put about 2hrs on it after, and parked for the cold spell we just got over. Ran perfect the whole time, thought it was finally good....

Went to hop on it for work Wednesday morning and the darn Main Fuse blew. VR connector is good, and no bad wires that i can tell, but it instantly pops the fuse upon touching it to the holder. I did have it on the battery tender, while stored. But i don't think the 'trickle' charge would cause enough over-voltage to pop the fuse. With key off, i get about 12.2 volts across terminals at fuse, turn key on and jumps to 13.6 Could this be a bad VR ? Thought it would only blow the fuse while running... Will dig more into the harness after work today and buy more fuses.
Anyone try using the 'reseting' circuit breakers for this ? Could help the pocket a little at $4/pop.

[wolfo68]

the mustang pump works, otherwise I have 2 spares in assembly as well as a spare walbro, let me know if you decide to order one

[wolfo68]

when mine was blowing fuses it was a loose ground (can cause all kinds of craziness)

check your battery connections then the main grounds