Repairing Intake Manifolds

Well after spending hours cleaning the carbs, replacing the valve cover gasket, and checking the valve clearances (all in spec) my stuttering when taking off in 1st and shifting up through 2nd and 3rd is gone. The bike runs great and is super responsive. Now, unfortunately, I've hit a little bump in the road. After the bike has time to warm up, it revs super high. I've seen a recent thread concerning this and it sounds to me like it's a classic intake manifold leak, or from the airbox. The air box boots to the carbs were kind of gnarly on the side connecting to the carbs and didn't have clamp on them. I've got them clamped down now and they don't appear to be cracked in any way. When I had them off, they were actually quite pliable so im crossing them off as the problem (for now). The intake manifold boots on the other hand are a different story. They are old, seem rather dry, and two of them have cracks long the edges where the clamps lock down. It didn't rev like this prior to my carb cleaning so maybe they shrunk a bit and i tightened the clamps too much. I had the carbs off for about a week. My best guess is that they're old and shitty and need replacing. I will resort to that if need be, BUT i'd like to explore a lower cost option if possible. Any tips on repairing those boots? I was digging into the idea of buying a roll of the self vulcanizing silicon tape and giving it a good seal. If anyone has in pointers, that would be great. Also after some brief shopping, all i've turned up as far as replacements is used ones on ebay (nervous ill just run into the same problem) and new reproduction gaskets (awesome) that are $70 a piece (not awesome). So any repair pointers would be great. Thanks everyone for your time!

-Nic

 

The classic, and time-tested method involves cleaning and degreasing the boots, filling the cracks with RTV, applying a coating of RTV around the circumference of the boots, and either smoothing it with a wet finger, or covering it with a length of inner tube. The self amalgamating tape can work, but it will slowly break down (I made that repair last summer. It held for as long as I needed it, but a repair that I made to garden hose three years ago failed from UV exposure). Some have recently started using electrical shrink wrap.

 

heres a few links provided by "xj550h" on the next page down, , someone was asking the same question
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Video of my Carb Boot Repair

carb boot repair-- heat shrink

Repairing intake manifolds with bike tubes
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second one down is my caferacer build thread
stu

 

That massive heat shrink is amazing. Slap some rtv down then shrink it... Should be damn near bulletproof after that. Having a hard time finding the 3" that isnt from China that will take weeks to arrive. Thanks for those videos!

 

Here is some I used to build up my tennis racket grip. It's nice and thick and measures about 5 1/2 inches in circumference. You would have to measure and see if that's large enough. It came pretty quickly.

http://www.ebay.com/itm/Tennis-grip...651847?hash=item3d07d8c547:g:0SgAAOSw0vBUfc7W

 

Found some 3" adhesive lined tubing. 4' for $12 delivered. We'll see how this goes.

 

I also used black rtv. Seems to be working well so far although I don't think the cracks in mine were all the way thru yet so it's hard to tell if it was actually a problem. I just did it anyway to be sure