Have a question for the group. I have a 1997 Soft Tail Custom with an SS Super E Carburetor. I recently had a new throttle cable installed. The tech also tried to tune in the Carburetor but was unable to do so therefore the Bike would turn over but not start. I had to trailer it home where my Brother and I were able to tune the Carb after about a half hour. She will start right up, idle no problem. She will ride strong with no problems with throttle or performance for about 1 to 2 miles and then the fuel starts cutting in and out with throttle then no throttle causing her to buck and lurch when the throttle hits again. If I let her sit a little bit she will start right up run strong again and then do the same thing again. Granted the day I took her for a test ride it was in the 90's so it may have vapor locked. Any suggestions on what it could be would be very helpful, thank you...John

 

Do you have a vacuum operated fuel petcock? If so get rid of it and install Pingel. Sounds like a fuel delivery problem..

 

No Sir and thank you for your response. When I got the Bike it had a stock almost impossible to turn petcock which I yanked and replaced with a Pingle which has worked great. I took the Bike for another ride last night after work, the temps were in the 60's and she ran fine, no trouble with fuel delivery so I am leaning towards the temps being to hot and causing the system to vapor lock on me. I have checked the lines, pulled the Float Plug (fuel clean), looked into the tanks (no gunk) and all looks well so I am hoping it was just the temps being to hot. The first time it happened was the first time I rode it after sitting all winter and half of the Summer in a shop that turned out to be a waste of time and money. I always fill my tank and treat it with Stable when I put Her away for the winter and She stays in a nice clean garage though not heated. I only run High Octane fuel, 92 -93 and here in Vermont the Ethanol is only mixed to 10%. I ride a lot so the fuel passes through the tank pretty quickly. Every fourth fill up or so I add a little Marvel Mystery Oil to the tank. I have been doing it since I got the Bike and I have never had any problems with my plugs or lines. I add it to my oil as well.

 

Have you check your float level?

 

Hey everyone I think I figured out what it was though some of you may not think it so. The day this all happened it was in the upper 90's regarding temps for the day. What happened was that the fuel delivery became "Vapor locked" causing an air bubble to form in the line thus cutting the supply of fuel to my carburetor. This had happened to me one time before a while ago and it was the same scenario then, high temps. I took it out the next night when the temps had fallen into the 60's and she ran great, no troubles. I rode her to work the next morning to see how she would handle a longer ride and again ---no trouble and it was a very nice cool morning. I have an older Bike with a gravity feed supply, no fuel injection or pump. Since then the temps have been no higher than the 80's and she has been running great. Tight on the throttle and no cutting in and out while I'm riding. Thank you all for the input, it is greatly appreciated!...John

 

I'd check the vented cap then if it's getting vapor locked.

 

I have Kuryakyn Flush Mount caps on my tank and there doesn't seem to be any problem with them?

 

There's a vent that permits pressure balance to avoid vapor lock either vacuum or expansion. find it and check it.

 

Yes I noticed a small vent hole on one if the caps and it states that it should go on the right side and the non-vented cap on the left tank, does that make sense or does it even matter? Thank you for your help Bro and everyone else as well...

 

Had the seem thing happen to me today.
Last time I worked on the bike I moved the fuel line from under the upper engine mount to above it to avoid the fuel line from pressing against the choke cable going to the carb. This was a mistake. As long as the weather was cool the bike ran fine, today with temps at or above 90 the engine would not continue to run, would start and get maybe a mile or two down the road then stop. Rest a couple minutes and would start run a mile or two and stop. Finally got about 4mi from the house and engine would not even start. Waited a couple hours and fired right up.

Figured that going over the top of the engine brace placed the fuel line in direct contact with the cylinder head, so the fuel in the line would vaporize and shut the fuel off to the carb.

Moved the fuel line under the engine brace and cured the problem completely.

So check your fuel line routing. Might help.