My FIL called me this afternoon asked me to take his bike (1998 XL1200) to get inspected. He hasn't ridden it all season but he had charged it up and it did start for me right away. As soon as I started riding away I knew something was wrong. When I roll on the throttle power dies and the bike almost sounds like it's getting flooded. It doesn't respond by producing more power.

Rolling the throttle in neutral causes severe backfiring from both the front and rear cyclinders and now, there is gas draining out from a vent tube that runs from the carb to the front of the bike (vent tube).

I tried draining the tank and refilliing it with fresh gas. Used some carb cleaner in the tank and some spray cleaner in the carb venturi (if that is the right term)...no help. Bike is still backfiring.

It idles fine - it just won't respond to increased fuel with more power.

Any ideas? Thanks for your help - my bike is a 2009 XL1200C with EFI - carbs are not my thing. I guess I need to get back to the basics.

 

To me it sounds like the carb probably needs taken off and cleaned/rebuilt. The slow jet sounds like it's gummed up & not spraying enough fuel causing the lack of acceleration/flooding effect. The fuel draing out the overflow is probably due to dirt causing the float to stick.

 

Thanks Hogrider - that was my assessment too. I'm probably not the right guy to try to rebuild the carb, but I'll pick up a manual and see if I can figure out the basics.

 

Heres a place for parts and tips and tricks for the CV.

Harley Performance

 

Freebird - awesome link. Many thanks!

 

Your Welcome.

 

Yep carb is where to start, could be a sticking float too.

 

I had about the same problem on my 96 1200c after hauling it several hundred miles on a trailer.
I took a siphon gun and hooked the siphon tube onto the carb inlet and held a white towel infront of the siphon gun nozzel and then hit the air.
Got a little crud out but noticed the fuel lines were getting mushy so I changed them to alcohol resistant fuel lines since we are now getting Alcohol blended fuel which will cause problems in old style fuel lines. Then I filled the new fuel line with gas and blew into the fuel line which backflushed the neddle valve seat area. No more problems. If you try blowing air into the new fuel line DO NOT make a direct connection with your air gun, only blow air gently into the line. This resolved the problem. The siphon gun I used develops about 5-7 inches of vacuum. Hope this helps,,,,,Mike

 

Update -

I took off the carburetor and removed the bowl. Cleaned the jets and tried to clean the float valve...I did not remove the floats (wasn't quite sure how).

Put everything back together and restarted the bike. It was still backfiring through both cyclinders but it stopped venting gas through the overflow (for a while).

I messed with the mixture screw in the bottom of the bowl (at the rear of the bottom)...first I leaned it in until the motor nearly stalled then turned it out 2 or 2.25 turns. Still backfires just off idle when there is a load on the engine, but it will smooth out as higher rpms. Once the bike starts coasting it starts backfiring again.

I didn't touch the top of the carb - didn't check the diaphragm for any damage or dirt. I ordered a rebuild kit tonight and a stage 1 jet kit from Harley Performance (actually, I had to order the rebuild kit from Bike Bandit since H P is out).

Oh, yeah - bike started leaking fuel through the overflow tube after I got done test running it and messing with the mixture.

Will update next week after I receive the gaskets and jets.

 

With the bike off, close the air fuel screw all the way. Then turn it out 2 1/2 turns. Then tune it from there.