Yamaha part number 16G-13569-00
https://www.fowlersparts.co.uk/parts/view/16G-13569-00 (number 3, PLUG, BLIND)
I never really noticed until pointed out to me, but if you balance the carbs yourself you'll know like i do that these caps can be a nuisance to remove, so after a few times will start to weaken and perish due to the cold weather and hot engine temperature changes all the time.
If they leak any air at all it can cause all sorts of problems.
https://www.fowlersparts.co.uk/parts/view/16G-13569-00 (number 3, PLUG, BLIND)
I never really noticed until pointed out to me, but if you balance the carbs yourself you'll know like i do that these caps can be a nuisance to remove, so after a few times will start to weaken and perish due to the cold weather and hot engine temperature changes all the time.
If they leak any air at all it can cause all sorts of problems.
More people are born because of alcohol than will ever die from it.