Rebuild first time fireup....a problem!?

Here's a pic of one of my carb to head rubber holders....

Pulled them tonight and they are all like this, although this one is the worse. As you can see, they have been on there so long that the rubber is impressed with the shape of the head port. This whole surface was also wet with gas, and there are also little radiating cracks in the rubber away from the hole.

I suspect that this is my problem. Now, as some of you know...I'm very poor and do things with a non-budget. I can't afford to replace these right now, so I'm wondering if I can smear some kind of sealer in there as a temporary fix?? Thanks!

You can smear a thin layer of black silicone rubber on the face of the rubbers where they meet the carb and the engine. Let it dry thoroughly before installing. It will work temporarily, but wet gas will eat it and it will leak again.

polkat wrote:

By the way, the engine had no gaskets between these rubbers and the head. I guessed that was because the rubbers are fully coated with rubber, and I assembled it that way. Right....?

No gaskets used there.

Might try this ---



Good Fortune!

I used Permatex spray sealant on my old ones, I didn't seem to have any leaks.



I just got new ones, but my old ones are in a lot better shape than yours. They are the VM26/28 style with the vacuum ports for the KZ1000. Not sure if they will work for you or not, but if so they are yours for the cost of shipping.

Thanks JakeB, but I have the Keihin CV34's, and I think yours are a different size.

I have a product here by Permatex called Moto 1 sealer, which is a rubber instead of silicon. Supposed to be good around gas. Think I'll try it....no?

polkat wrote:

Thanks JakeB, but I have the Keihin CV34's, and I think yours are a different size.

I have a product here by Permatex called Moto 1 sealer, which is a rubber instead of silicon. Supposed to be good around gas. Think I'll try it....no?

Depends on the temp range intended for the product.

The Ultra Copper Hi-Temp is for up to 750 degrees and recommended by Permatex for manifolds.

The spray rubber is good stuff, but for up to 350 degrees, and recommended for other things besides manifolds.

Don't know temp range of Moto 1.

I would use the Hi-Temp stuff and be done with it.

Good Fortune!

The Moto 1 is rated at 350 (with 400 peaks). It's in a squeeze tube like Ultra Copper. My only reason for resisting Ultra Copper is that I've had some pretty bad results using silicon around gasoline. Does that side of the head actually get past 350 degrees? Doubtfull, but if so, I'll grab some Ultra Copper.

Just to let everyone know incase it might help someone. I did seal the carb holders to the head with the Moto1 and what a difference! Runs very smooth now and the reving problem is gone! I will replace the holders when I can afford to, but I want to see how long this lasts. I do believe the other sealers mentioned would have worked just as well, but I used what I had.