My 2007 EGC (20K Miles) just decided to abandon me???
Last week I heard a hissing / chirping sound around the intake for the first time since new. Cruising yesterday at about 45-50mph engine backfired a couple of times and then acted like it was going to stall and lugs down on acceleration. Throttle up and engine regained composure only to pop and backfire again. Acts like a timing issue. Tried to limp home…did not make it! Could hardly keep it running and had to rev up to high RPM just to take off from stop light. Once I got it moving in first gear it seemed to run a little better in second and then it lost power again and lugged down and popped and backfired. Felt like it was running on one cylinder….Came to a stop and died. After sitting for awhile, it starts up fine then on rev up it begins to backfire.
Can anyone Please help? One person says he thinks it is related to Intake gaskets or “O” rings on the throttle body / intake?? What do you think???

 

I would start with checking for any intake leaks with a can of WD40 yet? It sounds like a leak is causing one cylinder to cut off and when it cools off, it runs a bit better then. If there is a leak you will hear a difference in idle and engine running when you spray near that area. You didn't say if you had any mods done to the bike or the last thing that was worked on.

 

If the intake is leaking,the motors running too lean.Thus the spitting and sputtering.

 

Another vote for intake manifold cracked, or seals leaking.

 

Could be a hole in the in tank fuel line. If you fill it up with gas and all is good then that is the problem.

 

Not necessarily so. If the line has a hole you are loosing fuel pressure and the result is poor running.

 

I found this post because I had the same thing happen to my '97 Ultra Classic (EFI). I have been trying to figure this out most of the summer. Well I found the issue. After removing the air breather and the back plate. I found a vaccum cover was missing. So I checked the whole throttle body out and found there was a second one on the horn side that was missing as well. Just replaced and cleaned everything and no more chirping!

 

 

This is a good down and dirty diagnosis for leaky internal line(s).
If the bike barely runs on low fuel and much better (albeit not perfect) when filled with fuel. What happens is with low fuel a hole in the line gets exposed so the pressure goes way down causing an excessively lean condition. Backfiring would be expected.
When you fill up the tank the hole gets covered over with fuel which helps to keep pressure up a bit making the engine run better.

Also if you have good hearing and the tank is low on fuel, open the fuel cap and stick your ear to the filler...turn the ignition on (with kill switch to run) and listen for the hum sound and pissing on a flat rock rather than a hum only.

The best way is to measure the fuel pressure with the appropriate gauge.
Common occurrence in those years. The new hose is shorter which keeps it from getting rubbed through creating a pressure leak.

Bob