TOPIC:

Hello All, I'm currently in the process of getting my carbs rebuilt, and while they're off, I decided to replace the carb to block insulator boots. My question is, do you need any sealant between the boot and block? I haven't removed them yet, but it looks like possibly some sort of sealant was used, as there's 'residue' coming from in between the boot and block. Now, I'm unsure if it is grime/dirt/etc from over the years, or if it is, in fact, sealant that oozed out during installation. It almost looks like dried wood glue. Looking at the parts diagram, there's no mention of sealant, and no O-Ring showed between the insulator and block, which would make me think you just install the insulators as-is. Any help would be greatly appreciated.

Thank you!

Originally no, so have probably been replaced previously. Given when new they were perfectly flat both sides, 40 years later, who knows. So a very very thin smear of RTV is what I would do. You don't want an air/vacuum leak there.

That's what I was thinking. The boots still look good, but I can see what looks like the beginning of a crack, so I figured might as well replace so I don't have to tear the carbs off again later on.

Thanks for your response!

Diloret2 wrote: Hello All, I'm currently in the process of getting my carbs rebuilt, and while they're off, I decided to replace the carb to block insulator boots. My question is, do you need any sealant between the boot and block? I haven't removed them yet, but it looks like possibly some sort of sealant was used, as there's 'residue' coming from in between the boot and block. Now, I'm unsure if it is grime/dirt/etc from over the years, or if it is, in fact, sealant that oozed out during installation. It almost looks like dried wood glue. Looking at the parts diagram, there's no mention of sealant, and no O-Ring showed between the insulator and block, which would make me think you just install the insulators as-is. Any help would be greatly appreciated.

Thank you!

New carb to block connectors may be fitted without using any sealant.
Be sure the block mating surfaces are perfectly clean and smooth and undamaged.

Many different sealants have been tried, and some seem to work for at least short time, but it's difficult to find a sealant that withstands both heat and fuel for a long time. Maybe 3 bond would hold up a little longer than silicone.

There are many earlier threads here on this subject -- mostly about what fails to last very long.
Would suggest doing a forum search and reading the articles. And likely decide to forego using any sealant.

Good Fortune!

Install new ones dry.
Steve
jetsrus.com/mounting_flanges/mounting_flanges.html

Thank you both for your input!

I already have the new boots, we are supposed to have a warm day here on Wednesday, so I'm hoping to get the old boots off them and check out the surfaces.

Thanks again!

Please note that the screws may be corroded and really difficult to remove. It would be a good idea to be soaking them in some good penetrating oil for the next couple of days. Also, you need a properly fitting screwdriver. Though they look like Phillips head screws, they are actually JIS. A genuine JIS screwdriver or a suitably modified Phillips driver will greatly reduce the likelihood of damaging the heads rather than removing the screw. A hand held impact driver woul be great, but with the air filter box in place, there is not enough room.

Thanks for the advice. I do have a set of JIS screwdrivers. I believe the bolts in mine are Allen head, though? Which would lend itself to the theory that these have been replaced at some time or another.

Getting those screws out with a regular screwdriver will be a challenge. An impact driver with a phillips #3 bit will do the trick but that assumes you have room to swing a hammer. I know everyone here always talks about JIS screwdrivers and how important they are, and I agree, however, I'll tell you that a standard #3 bit is fine for the larger size KZ screws.

Oh, and install the boots without any sealant. That's how Kawasaki did it. Sealant on carb boots is a temporary bandaid at best.

No sealant is needed. If you find sealant on yours someone has been in there before. I replaced the carb holders on my KZ650 14 years ago (more than 20,000 miles) when I found the originals had hairline cracks that were affecting idle. I used no sealant and they still do not leak at all.

The screws that attach the carb holders to the cylinder head can be extremely difficult to remove. I HIGHLY recommend that before trying to loosen those carb holder screws from the block that you soak then for a couple days with Kroil. I soaked the screws on mine for 3 days and they came out with no problems at all. Also, be SURE to use a JIS screwdriver NOT a Phillips, otherwise you will mess up the screw heads. If you need further info regarding the JIS screwdrivers just ask. Ed

If they are Allen head, someone has been there before and as Warren3200gt has said a light smear of RTV will help if there are scratches on the alloy surfaces.

Well, I had Allen head bolts, not JIS screws, and they actually came off without needing to soak them. Just took an Allen wrench and a small pipe to help break the bolts loose. The sealant that was used on it was very plyable and peeled right off. The seats cleaned up nice with some carb cleaner and a rag, and were very flat with no blemishes. So, I just bolted them on without RTV. Now just waiting on a slightly warmer day to try and jam the carbs back on. Thanks for all your help guys!