Inlet manifold leak ?

[RJ9993]

Hello fellow 1300 enthusiasts. I purchased a low millage 1983 Voyager imported from Japan 12 months ago. This bike has the US VIN # so I'm guessing it was a personal import to Japan. I have the same over heating problems as everyone else which I'm working on now. The radiator will be flushed, new thermo installed & a stainless nut put on the end of the shaft to stop the bypass valve closing completely. Unfortunately the bike did over heat on a recent ride. I switched the engine off & allowed the bike to cool before starting it back up. There was a noise that sounded like an air leak or the inlet manifold sucking air. This noise increased with revs. I checked the clamps on the engine side of the manifold & found the right one was loose with fuel resin around the clamp. Tensioning this up did not stop the noise. The next day I discovered there was no noise on a cold start. Once the engine warms up to operating temp, it comes on & increases with revs in neutral. It is not as noticeable once I'm riding. I haven't pulled the plugs to check for signs of a lean burn. Anyone have any ideas. Thanks. RJ

[trikebldr]

No, you're not being ignored! It's just sounds like a strange issue!
Although I have two of these 1300's, and had a brand new '83 decades ago, I have never heard of such sounds. Mine have always run quite well. Too bad we can't post sound tracks on here so we could hear those sounds you describe. What's puzzling is that it comes when the engine is warmed up! Anything on the intake side shouldn't react that way. Have you checked the air bypass covers and system on the top of the engine yet. They would make the sound you describe as well as be affected by engine temp. Gotta pull the gas tank off to check them. Might look around each exhaust pipe right at the head for any signs of leakage, too.
Buying any used bike means taking a chance on how the PO's have ridden it and cared for it. Since it has a U.S. serial number on it, probably owned by a military person who shipped it over there while he was in Japan, then decided he didn't want it bad enough anymore to ship it back.
Would love to work on yours with you if you lived closer! Sounds like an interesting problem.

[Me Again]

While you had it apart did you check the circlip on the water pump ? Although I think the sound would be a little different it is one of the main causes of overheating .

[trikebldr]

RJ, one of the best ways to locate the exact source of a noise is to use a 24"-36" length of 1/4 fuel hose stuck in your ear, then move it around to find the noise. It WILL show up very loud when you get close!

[RJ9993]

Thanks everyone for the feed back. She's still up on the work bench. I've decided to ceramic coat the headers & have the mufflers opened up. Once she's back together, I'll check for that noise with the tank removed. Cheers RJ :)