I have a '98 FLHT (carbed EVO)and I have a running issue.

When I am at cruising rpm, and sometimes during acceleration, I get a brief slight power loss and a "POP" which I think is coming out of the carb. It does this fairly regularly, but not always, and it happens at a certain part of the throttle (I can almost tell when it is going to happen based on feel). If I go above or below the spot in the throttle, it does not do it. Just seems like it is at that one spot.

I have played with the mixture very slightly, but no improvement.

I think I am just going to replace the intake gaskets and rebuild the carb, but would like to at least try and diagnose it before I do so, just to learn. If its simpler than I am making it, that'd sure be nice.

Any thoughts or suggestions?

(and sorry if I did not provide enough info, let me know what other info you may need)

Oh yeah...a can of Seafoam didn't fix it...

 

Intake manifold seals, or carb to manifold seal. Or both.

Quite possible your carb needs a good cleaning. How's the idle???

 

You might have solved it by saying intake leak. Maybe even Exhaust leak.? Carb Pop, Advanced timing.?

 

Most likely jetted too lean. Mine was doing that. Took it to a good independent shop and it's all better now.

 

Exactly like my bike was doing at 70 mph. Roll the throttle on easy, and it would 'miss' and pop out the carb.

New manifold seals and a clean carb, solved the issue.

 

My 87 FLT had a kehin butterfly" not a CV" carb that did that. tried lots of things to fix problem, "adjusted timing, intake seals, exhaust seals, riching up fuel mixture, etc." Ended up chunking the thing over the fence, "the Carb.", an put on an S&S super "E", Problem went away. I'm pretty sure it was a lean condition caused by the old Carb. Used to get around 40mpg with the Kehin, now getting 35mpg, Oh well!!! She don't spit in public no more.
Killer

 

My '86 had a problem due to the accelerator needle not seating under nozzle resulting in no gas squirting on 2nd twist of throttle.

 

All things to check, you can use carb cleaner and spray around the intake seals, listen for a change in rpm that would indicate a leak.
Another thing would be the cable adjustment, had this happen before turned out cables were out of adjustment and when the acc. Pump sprayed it would hit the butterfly, you could smell gas and would get a pop when the"puddle" would get sucked into the air valve on the carb.
I also just did the exhaust gaskets on my 06 last guy never tightened the bolts and two were gone the other two just on, it was pretty evident by the pop and you could tell there was a leak by looking at it.
If you guys have a winter like us now I would be rebuilding the carb with cvpreformance parts, new gaskets intake and possibly exhaust while you have the time. The cv Caribs easy to work on and you will gain another level of understanding your ride.

 

Thanks for the replies. I didn't get to do much on it this weekend, just a lot of cleaning and waxing.

Will do the carb cleaner test this coming weekend, then pull the carb and rebuild it and replace all the intake/exhaust gaskets as I get some free time this winter.

Hackd, the idle seems fine.

 

After running at highway speed for a bit, and then going to a stop, does it seem to idle higher than normal? Or does it consistently settle down to the same RPM?