Carb Boots

[Glyn.G]

Hi Everyone,
It's been a while and 8 years since I restored my 1977 GT380 and it's still running well but yesterday whilst out for a ride I noticed the idle speed rise to 1500 revs. When I got home I had a quick check round and found the rubber carb boots/sleeves had split and started to turn to a sticky mush. It is only the two outer ones that have split and the middle ones are still perfect.
Has anyone found an answer to this sticky problem or should I just take this as the norm. I thought maybe covering the rubber with a thin smear of silicone grease inside and out, but I don't want to make them rot even quicker.
Cheers for any help you can provide,
ATB,
Glyn.

[Craig380]

Do you mean the rubber bellows around the carb slide lifter rods, or the actual carb-to-cylinder mounting rubbers?

If it's the rubber bellows, don't worry, just adjust the idle down and maybe tweak the pilot screws a little. My old 380 ran perfectly well with totally perished bellows for 18 years. While a little extra air might get drawn in at idle (when carb vacuum is high), as soon as you're riding that extra air is negligible compared with what's going through the carb venturis.

[Glyn.G]

Do you mean the rubber bellows around the carb slide lifter rods, or the actual carb-to-cylinder mounting rubbers?

If it's the rubber bellows, don't worry, just adjust the idle down and maybe tweak the pilot screws a little. My old 380 ran perfectly well with totally perished bellows for 18 years. While a little extra air might get drawn in at idle (when carb vacuum is high), as soon as you're riding that extra air is negligible compared with what's going through the carb venturis.

Yes it's the rubber bellows, I already have a new set to put on but I just wanted to know if there was a solution to the problem as it looks a mess when they perish.

[Craig380]

Those bellows just don't seem to last anymore, perhaps it's the change in fuel composition over the years or maybe they're just made of an inferior material now. But yes, they turn into a horrible sticky mess.