Stumped by a damn bing!

Hey y’all, haven’t posted on here in forever but here I am! I have a Ktm Foxi with an e50, 14mm bing and 65cc airisal kit. I’ve had this thing for almost a decade and it’s always been suspiciously reliable.

Lately its been acting up and I’m stumped. It will start but as soon as the rpms get up it dies on me. Sometimes if I let off the gas if will still idle. It very much feels like it is starved for fuel. Last time it died I went ahead and pulled the float bowl. There was a little bit of gas in there but it definitely was not full. Here’s where I’m confused:

1. The carb is clean all passageways aren’t clogged when.

2. The banjo fitting is definitely lined up correctly for max flow

3. I can see fuel in the line and it flows freely from the petcock if I pull the line.

4. The float height looks good. I bought a new one and threw it in just in case mine was bad, problem persists

5. It ran well for years with the current set up/jetting (I think jet is a 78)

I’m stumped. I’m hoping I’ve just been away from peds for too long and am missing something obvious. Any help is appreciated!

Re: Stumped by a damn bing!

Richard Eberline /

gas tank cap or bubbles in fuel line.

Re: Stumped by a damn bing!

There is a tiny little thimble looking filter in the banjo bolt, it doesn't need to be lined up to anything. Also the banjo spigot nipple thingy can corrode closed, I had that happen a few years ago and messed me up.

If you want to test it, leave the bowl off and install everything else as normal, see if gas pisses out.

If you are stuck running ethanol gas, start adding some stabil marine in there.

Re: Stumped by a damn bing!

Graham: I pulled the filter out of the banjo and the passage way is looking good in the banjo but good thinking! Gas is flowing.

I’m wondering now if an air leak is causing my carb to loose vacuum. Gaskets are definitely ready to be replaced but I’m not sure that would effect the flow so drastically? (edited)

Re: Stumped by a damn bing!

roots to wings /

If it's not what Graham said, meaning there aren't any snots in your banjo, banjo thimble, or the hole the fuel goes into the bowl thru, or snots in your jet, or chunks in your fuel filter, I'd be thinking condenser or points and timing.

Re: Stumped by a damn bing!

^bingo^air leak change out your crank seals, search for air leaks. You can test by enrichening your mix with extra gas, choking with your thumb, or tickling the tickler on your float bowl.

I know its a pain removing installing carb but adjusting the float to have a correct amount of fuel level is important.

Re: Stumped by a damn bing!

I'm betting it is less to do with the float itself but the float needle may be sticking and not letting fuel flow properly into the carb while riding at speed. But it trickles down and refills the bowl by the time you can get it all off to check. With a bing and fuel delivery issues it is the first thing I check and replace.

Re: Stumped by a damn bing!

roots to wings /

I was working on a new bike this morning and my float level was just a little off and combined with a slightly roached float needle causing the carb not to fill. I agree to make sure the bowl is filling

Re: Stumped by a damn bing!

I end up going over to a sha. But that is not exactly going to be an easy swap or straight forward tuning either. I just end up having better luck with my sha setups than my bing setups. They are two completely different animals tho.

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