Motor Choking Out At 50 MPH

[baja]

I have a 92 Softail that was stalling at idle and backfiring when I let off the gas. I changed out the jets and the manifold seals and the backfiring stopped but now I've got a new problem. Once it gets up to about 55 and I keep it there, it starts to sputter and sometimes completely cuts out. It seems like it's starving for fuel. I had blown some compressed air into the slide piston so I thought maybe I damaged the diaphragm. I changed that out but no luck. I just cleaned the whole carb really well and changed the gasket on the float bowl.
When it starts to sputter, if I lay off the gas for a couple of seconds then roll back onto it it has plenty of gas and get up and go, but then it will sputter again and the whole thing starts over. From a stop it'll take off and get up to speed fine. It's just once I'm up to speed and remaining at a constant speed that I have this problem. It's like my float is sticking or something, but I'm not getting any overflow of fuel when I'm stopped. Somehow I'm using more gas than it's supplying at a constant speed. Kinda stumped and looking for some advice. Thanks in advance for the help.:newsmile07:

 

[HDDon]

Do you have an inline fuel filter? Have you taken the petcock out and checked the screen? Do you have the original type petcock or aftermarket? Do you still have the VOES or aftermarket ignition?

 

[baja]

I havent taken out the petcock or checked the screen. No inline fuel filter. I think the ignition is stock. It's a used bike so I'm not positive. I wasn't having this problem before I removed the carburetor and cleaned it. I'm wondering if I screwed up the accelerator pump somehow. The only problem I have is maintaining speeds at about 1/2 to 3/4 throttle in top gear.

 

[fin_676]

From the description of the problem i would guess that there is insufficient flow of fuel to maintain a sustained use
first thing i would do is pull the fuel line off the petcock and see how the fuel flows from the petcock
also check that the fuel line is not pinched reducing flow to carb there is a hole in the centre head steady to accommodate the fuel line if it is not routed through that hole it would be pinched between the head steady and the manifold

Brian

 

[Bodeen]

Fin has got you covered here. Fuel flow problem. Check the petcock screen and fuel line run. After that, the fuel float adjustment maybe too low. You may have inadvertently changed the float adjustment when you had it apart. Let us know what you find.

 

[glider]

From the description of the problem i would guess that there is insufficient flow of fuel to maintain a sustained use
first thing i would do is pull the fuel line off the petcock and see how the fuel flows from the petcock
also check that the fuel line is not pinched reducing flow to carb there is a hole in the centre head steady to accommodate the fuel line if it is not routed through that hole it would be pinched between the head steady and the manifold

Brian

I agree with Fin. It sounds like fuel isn't flowing from the tank enough to feed the engine at 55 MPH. Time to pull the tank and clean it out as well as removing/cleaning the petcock and screen then replacing it and fill with FRESH gas.

 

[TQuentin1]

I havent taken out the petcock or checked the screen. No inline fuel filter. I think the ignition is stock. It's a used bike so I'm not positive. I wasn't having this problem before I removed the carburetor and cleaned it. I'm wondering if I screwed up the accelerator pump somehow. The only problem I have is maintaining speeds at about 1/2 to 3/4 throttle in top gear.

Unlikely it is the accel. pump. That works when you open the throttle quickly. But it is a very simple device, so open it up and clean it out. Make sure the diaphram is OK, and chase the port with carb. cleaner spray.

As said above, probably junk in the tank restricting flow. You might consider replacing the petcock with a full flow from Pingel. That will give you a new sock anyway. Clean out the tank and make sure the internal coating is not coming off. If it is, it needs to be cleaned out, stripped and recoated.

Power-Flo™ Fuel Valves

TQ

 

[Jack Klarich]

Check the gas cap, is it venting and not creating a vacuum in the tank?

 

[baja]

I'll check those things out and be getting back to you guys. Thanks a ton for all of the replies!!