Not a solution to a world problem but I have been unhappy about how short a time the rubber vaccum caps (squirrel condoms) have lasted on my bikes. Found some silicone caps that are used in powder coating industry (from Eastwood via Amazon). The 0.140 inch version is a good tight fit to the vacuum ports on the carbs/manifold, but it only comes in white as far as I can tell, and it is rather thin walled so was afraid it would blow off at the slightest engine stutter. So, what to do. Using a black rubber cap that the white silicon cap fit into I trimmed off the silicon cap to match then used a spring clamp to keep the whole thing on the port. So far it seems to be working and I am hoping that the silicon insulates the rubber from the heat a bit and will make it last longer, but even if it cracks the silicon will keep the port sealed.
Please note that the spring clamp pictured is a larger size than the ones I used but didn't have an extra smaller one to photograph, and please forgive the low quality cell phone pics.
