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Discussion Starter · #1 · (Edited)
Fixing an air leak and I can't find a clear answer on this so I wanted to pitch it to the experts:

What is the proper way to affix the rubber carb boot to the cylinder head? I've read on here that if you torque it too hard, you can bend the metal base and cause it to seal incorrectly; but does it seal correctly with just a dry gasket? Is there any Hondabond or sealant needed, either on the gasket surface or around the edges once it's attached? This is the second time I've dealt with a carb boot air leak on this bike (with new boots, to boot), and I'd like to put it to bed once and for all.
 

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Are you using hex bolts? The originals are JIS screws, which are tough enough to tighten without stripping using a Phillips head, let alone overtorque. I don’t usually encounter leaks between the head and the boot using new gaskets - it’s generally the old boot rubber being cracked (or expanding to crack when heated). Are you using new boots?
 

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Discussion Starter · #3 · (Edited)
1) Yes, I'm using hex bolts which were what were on the bike when I bought it. No idea that Phillips head screws were OEM spec.

2) Yes, the boots are/were brand new, though at this point (1+ year after rebuilding) I can't remember if I bought new Honda-brand insulators or the much cheaper generic reproductions. Regardless, I'll surely spring for the $40 Honda boot this time, but I want to make sure I put it on properly as well.

Edit: Also, the leak was definitely between the boot and the engine; when I removed it to check I could see where the gasket had been blown by, and the metal of the cylinder head surface was a different color than the rest where the gasket had been sealing it.
 

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Interesting. I’d use very gentle torque on those, they don’t need to be He-man tight - honestly, if you’ve got a screwdriver style handle for your sockets, I’d use that. Keep in mind how much easier it is to apply loads of torque with a ratchet handle than a screwdriver, which would explain how you might deform the plate.

I’ve had better luck with Honda boots than eBay specials, though the $40 does bite. I’d just make sure the head is clear of any remaining gasket material and then screwdriver tight with fresh gaskets. No other special tricks to my mind, though others may chime in.
 

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use honda boots, use correct fasteners, use honda gaskets, coat with permatex copper spray for a little extra protection.

before installing make sure your gasket surfaces on the head are perfectly flat and clean. add a dab of blue locktite to screws

install with screw driver and they will never leak
 
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