squeaky backfire

[passingwindII]

i have a yam 40tlrt 95'.

have developed a backfire that resembles an intermittent chirp. the chirp is coming from the #3 cylinder. I've switched coils and plugs. still chirp comes from #3.(i know this because when i pull the spark plug wire off #3 it stops).I've cleaned all carbs. I did notice when i put my hand over intake of #3 the chirp stops.

i havent run a compression test

ty in advance

 

[99yam40]

Re: squeaky backfire

Do a better cleaning job on the carbs and make sure you do the link and sync as described in the service manual every time you reinstall the carbs