Squeaking chirping sound from front cyclinder area

[skaalster]

Good day fellow Visioners, I parked my freshly restored  82 last night after a evening run, she's been running great this last year but have definitely seen a recent reluctance to start lately when the engine is warmed up/hot but the probably another issue.
Upon starting her up this morning she was difficult to start, and emitted a strange and unnerving chirping/squeaking noise which seemed to be emanating from the front cyclinder area, not metal on metal sounding almost like a loud rubber squeak sound. Ive pulled the tank/filter and checked all my vacuum hoses and everything seems tight. It was definitely related to RPM in either a compression or exhaust stroke and got louder as I rev the engine. Not wanting risk damaging anything I shut her down. I've done a quick search of the site and have only found a reference to incorrectly installed carb boots (on backwards) and I replaced both boots with new ones including seals over a year ago and don't think that's the problem.
So..maybe a Loose exhaust flange? leaking head gasket? Going to head to my shop and pick up a stethoscope to try and narrow down the exact area this afternoon. Any and recommendations or ideas would be greatly appreciated. Thanks in advance -Daniel

[jefferson]

The first thing I would check is the 4 screws that hold the exhaust pipes on. They may feel tight enough, but tighten them some more (just don't go too tight and strip them) and see if that changes anything. May need new gaskets in there.

[skaalster]

 Well I've made some progress, so far I ruled out that it was the front exhaust flanges,  sound direction is definitely subjective for my old ears lol  apparently the gas tank was channelling the sound from the carburetter area to the front of the bike...I blocked off the YICS (it's good, well sealed) removed the vacuum to the fuel pump and I blocked off all other vacuum connections and it still squeaks like a son of a bitch, when turning it over and when running.  Took some video which illustrates the sound pretty good  but not sure how to upload to the site. 
Removed the entire carburetter assembly and when I turn it over there's no squeak and before and after it flashed up momentarily..  so it's definitely in the carburetor somewhere.  I did note that when I removed the Carb assembly there was some fuel between the boot and the carb at the rear intake cylinder..don't know, maybe it was squeaking there? Inspected the elbow intake boots and they look solid and are nice and tight to the engine... other than the actual engine intake, without any vacuum connection to move diaphragms etc. not sure how that sound could be coming from the Carburetors. Hmmmn...going to disassemble them now and see what I can find.

[Walt_M.]

Do you have the vacuum operated flapper in your airbox? It could be a ruptured diaphragm in the actuator. Just trying to figure what could make a squeaking sound in the carburetor area.

[Struuner]

I had the butterfly linkage Rod end scraping Just the top of the forward cilinder carburetor boot bolt. It made a awefull squeaking sound. Now, that would go away when giving gas, as the Rod moves away when throttle open. But perhaps, you have some thing different Just touching and scraping causing the noise.

[skaalster]

Well figured it out with the help of some fine folk on the FB riders of vision page. After dismantling reassembling my carburetter thinking it was maybe a fuel pump issue, i discovered that the brand new carb boots and gaskets that visually appeared  sound after inspection were in fact warped with a1/8 gap between the mating surface and the incorporated ring seal (grrr cheap knock off parts) the surprisingly thin gaskets that came with the kit were singing (chirping)  like reeds in a musical instrument in between the gap with every piston stroke. It sounded cool but certainly made the bike run like crap. Thanks for all the suggestions. Time to make some new (thicker) gaskets and with some high temp gasket maker to fill in the gap, hopefully fix the problem. Cheers -Daniel

[fret not]

Congratulations on your victory!

[Lucky]

Great job, and I'll bet you had that stethoscope huh? :)

[skaalster]

Certainly would have helped in this situation Lucky!  lol...bought one years ago..but have never used it cuz it's buried somewhere in my shop and never handy...I learn something new about these bikes every week it seems. You guys rock! 😊👍🏻 Bike runs like a champ now!

[skaalster]

Hopefully this pic loads up to illustrate the gap on the aftermarket boots I experienced. FWD intake was good but did the same repair on it as the rear. (thicker gasket and some high temp gasket sealant lightly appalled to both sides of the gasket, lightly bolted into place till it hardened and then torqued down) both carbs were then re-synced with carbtune and WOW!! she runs better than ever...no dead spots throughout the rev range...feels like a whole new bike. Very happy as the "stumble" and uneven, hunting idle has plaugued me since I finished my resto...just couldn't get her to run like I felt it should. A rooky mistake I hopefully won't make again👍🏻😊