Hissing noise

I own a 1997 Harley Dyna Low Rider, it has a CV carb that was rebuilt not to long ago. About 12 thousand miles on the bike.

Yesterday I started it up and heard hissing sounds coming from the engine, can't really tell where it's origin is. I noticed when I pulled the choke out the engine runs very fast, a lot faster then it used to when in neutral. I also noticed that there was a wire coming from the Carbuerator Enrichener knob that had been touching the head, and it was burnt, but not all the way through...looked like it wasn't damaged. It's not a constant hiss, just when the engine turns over. It runs, but coughs and backfires more now. I checked the sparkplugs and the oil and they were fine.

Anyone had this problem before?

Seems like an intake leak....take an unlit propane torch and with the bike warmed up and idling check around your carb to manifold mount/seal and manifold to head mounts...if the idle speeds up,you found your leak...

vacum hose off the back of intake to pep **** ? happens some times when they cough!

Thanks, I checked it and the hose is still on. For some reason I'm thinking it could be a bent pushrod. The engine runs, but not good.

"bent pushrod" making a "hissing" noise?!?!?!?

I concur with Lucifer. If you're not comfortable using an UNLIT! propane bottle, try spraying WD-40 around the connections. It's a little messier, but you'll have the same results.

I did what you said, I have a propane torch...The idle did speed up, so I figgured there was a leak like you said. I replaced the seal ring from the manifold to the carb. It helped a little but still have the same problem.(Itried the torch again) The intake manifold seals were replaced a little over a year ago (05/13/11) at the Harley dealership in Lakeland Florida. I may take it back there and see what they say, maybe the seals failed that they put in. It cost me $180.00 to get the work done, hope I don't have to get it done again.

Thanks for the info

When mounting the Carb to the manifold, it's a good idea to lube the seal with dish soap,vaseline WD40 or KY jelly LOL....helps the Carb slip in and leave the seal in place .... did you notice a change in idle when you put the propane around the manifold flanges??

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I took the carb back off this morning, did what you said...lubed the seal with WD-40, pushed it on as hard as I could. I put it back together, started it up and now it seems to be running fine..I tried the torch again and didn't get any faster idle speed, so I'm hoping its good now.

Thanks for your help

Jack

Thanks for all your input, I did what everyone suggested and my bike is running like new, you guys are great...I was splitting the breeze today, and I had a blast. Thanks for all the help.

Glad it was an easy fix and you have your knees in the breeze again.:biker:

$180 to replace intake seals. Yikes! They value their time VERY highly over there. I'm an amateur and it takes me about an hour and costs nothing but the cost of the rubber bands.

Glad you fixed the leaks and got on the road again.