Used (16065-1135) carburetor holders

Anyone know a trick to attaching previously used (excellent condition) carburetor holders to achieve a good seal?
The set I put on yesterday was originally mounted for a short while on a different head, and removed/stored for future use when that head was replaced a couple years ago.
The rubber mating surface is well-molded and heat-set with no cracks or checking, but the rest of the holder rubber is pliable.
The set does not mate well, but allows some outside air to get sucked into the motor. I did not use sealant when installing them, figuring they would just re-shape to this head when tightened down, but noooooooooo... I tested them by spraying carb cleaner onto the joints while the engine was idling, and there were noticeable changes in idle speed.
So, what's next? Perhaps it makes more sense to just get a new set. I don't want to risk sucking something used to seal them into the motor.
It seems like a good place for an O-ring.

Are they supple, soft?
I have read where Wintergreen oil will soften them up.

They are like new, except the contact ring at the head. That is where its like plastic from the heat.

I use Kawibond sealant. It's fuel resistant. If there's any doubt, Dont use them. Few things will damage an engine as quickly as a lean condition caused by air leaks. For me, they look good. Use some sealant.

I would replace them. Sealant usually only serves as a temporary fix at best. The good news is that Kawasaki.com shows them as "Active" so they should still be available. Partzilla lists them at $16.45 each. Ed

find.partzilla.com/?r=t&q=16065-1135&x=6&y=6

You might also check with Z1Enterprises. They show an equivalent set for $60.30

Sorry about my typo in my previous posting. The price is $16.45 each NOT $126.45 each. I fat fingered that price badly! I went back and corrected it. Ed

LOL. I thought you meant per set of 4. Not much more than Z1E.
I bought mine at Z1E and r\they work great.

Any thoughts on OEM Genuine Kawasaki vs. K&L (regarding quality), regardless they have the same part number molded into the rubber? Perhaps a less-costly, inferior rubber compound is used in aftermarket manufacturing.
What I'm getting at, is the price disparity between OEM and aftermarket. An example...K&L carburetor kits for the BS34 contain fuel float valves that are not quite the same as the OEM Genuine Kawasaki (Mikuni) part. The OEM float valve currently sells for twice the price of a whole K&L kit! On close inspection, the parts are quite different, though designed to do exactly the same thing (which one does flawlessly).

ZERO wrote: I use Kawibond sealant. It's fuel resistant. If there's any doubt, Dont use them. Few things will damage an engine as quickly as a lean condition caused by air leaks. For me, they look good. Use some sealant.

What if a swatch of rubber sealer breaks loose and gets lodged between the valve and it's seat? :ohmy: OUCH!

Yamabond #4 works great. Probably same as the kawasaki bond. All you need is a thin coat of it. No worry of sucking any into the engine, and even if it did, no adverse effects would result.

Then you've used too much! I'm talking about a skin of it. Funny thing....I just rebuilt an engine for a friend and he insisted on re-using his intakes with deep cracks visible. His fix? black R.T.V smeared all over the outside. Generally, just put on a smear and spread it with a finger on the attaching surface. Install the intake and then, with a rag, wipe off the extra from the inside with a rag. I've never seen an issue with an engine swallowing sealant and doing engine damage. I've been doing this for nearly 40 years.Valve springs are strong. seats are smooth....Not a nice environment for rubber sealer.(I HAVE seen spark plugs fouled with a chunk of it.) Its also neat to use allen head bolts instead of screws and find some small washers to fit underneath. Really, the best thing to do is replace them..each time. But to me, yours look good. (enough) Only my 2 cents.