Topic: Making Rubber Intake Manifolds

[BobbyR]

I know I have a poor seal between the Carbs and the cylinders. The rubber is age hardened and the aluminum clamps are stretched. I once read that you could use Auto radiator hoses. Anyone try this? I am sure we need a specific bends so there are some car hoses that would work better than others. If some one has a better solution I would like to find one. I won't buy a used set since they would be no different than what I have now. I am doing a refresh on this bike again, as I intend to keep it another 20 years.

[Sam Green Racing]

Bobby,

useing auto rad hose will cause gas flow problems as the inside diameter of the hose is the same size as the outside diameter of the carbs and stubs.
The Honda rubbers flow the same diameter of the carbs and inlet tract.
They would work, but would impair performance.

Sam.

[ElCheapo]

Which ones are you after? Chances are that I might have a set. Sam is right that the O.E. rubbers are always best.

[Sam Green Racing]

Two heads would need eight rubbers 

[BobbyR]

Cheapo, I have a 1978 750K. I am looking for the manifolds from the carb to the cylinders. The manifolds from the airbox to the carbs probabaly have a lesser effect. I get the usual having to run with the choke on till she really warms up. The clamps are shot so I have scare up a set of those also. If worse came to worse, I would just "glue" the old ones on with some hi temp to seal them, but that is half assed at best. 

[ElCheapo]

I have a set for you. Pm or email me I will get you hooked up. Mine also have decent clamps.

Morale of the story,
ElCheapo has what you are looking for 

[Raul CB750K1]

...no matter be it bike or auto parts, or food-in-a-can smuggling!!!!!

ElCheapo, your one-stop-shopping for ev'rything you may need. Got Viagra?   HAHAHAHAHAHA




Raul

[scott_cb650]

My rubbers were super hard, like plastice, when I took them off. 
I had to use a hot air gun to remove them.

I soaked them in Berryman solvant for about 14 hours and they came out "like new".
Interesting part was that the carb side is softer than the engine side.

[eldar]

I have also heard of ways to rejuvenate rubber. I would not do it for tires but for these manifold rubbers, I would. As long as you have a seal, you are good. 

One thing about the radiator hose. What if you got a smaller size that had to stretch a little to fit the ports? The hose then would not have a larger diameter and you would only have the seam which you have anyways. Anyone try this idea?

[ElCheapo]

If it is the screw in manifolds or the rubber bits, I have both.

[Uncle Ernie]

Are you in the parts biz? Got a 400 that I've been running pods on forever because the rubber connecting my airbox is shot. It's been so long I can't even remember what it looks like, but I'd like to go back to stock if I could. Might you have the stock item(s)?

Scott- what's this Berryman's stuff? Sounds English maybe. Anything like that in the 'States?

[ElCheapo]

Yes, I am in the part BIZ.

I do not have those parts as of right now. I do however have great memory and will keep you in mind if decent part comes along.

[cbjunkie]

http://www.haysoil.com/berrymans.htm

doesn't seem to have a webhome of its own...plenty of reference to it i all the other bike forums...


waitaminit...you mean there are OTHER bike forums???   

[scott_cb650]

It's the best carb dip and cleaner.
http://www.berrymanproducts.com/


I use the gallon can for dipping: http://www.berrymanproducts.com/Default.aspx?tabid=146
and the spray for jets and directly into the air intakes: http://www.berrymanproducts.com/Default.aspx?tabid=138

[judder]

Anybody ever use brake fluid to soften the rubber on the intakes. Brake fluid hates metal but likes rubber.

[754]

If I could find some casting rubber that is fuel proof, I would try to make my own for  our Weber setups.

 As far as using straight hose, it works on the Webers, but is not perfect.. so perhaps , we could see a gain, if we had proper, stepped  manifold connectors..

[bucky katt]

is the radiator hose fuel proof? , i cant believe this isnt something i've thought about before.

[BobbyR]

is the radiator hose fuel proof? , i cant believe this isnt something i've thought about before.

WOW you found a thread I started in 2005. The answer is I don't know, but if you swapped them out often enough I guess it would not matter. I was desparate and I found something about doing that on the web, you had to find the right hoses with the right bends.

Mike Reick contacted me and set me up with 4 new Hondas and clamps and I never looked back.

[754]

 On the Webers the spigots are just about touching. It seems way back in the 70s, I found some tubing that fit easily.

 But a couple years back when I looked, I had trouble finding something that would fit.. not that the ID is hard to find.. It is the fact a lot of hose is double braided and wont  stretch easily to fit over the spigot, with the ID being near port size.

 It ended up I used hose that was double braided, and had to strip off one rubber layer and one braid layer tto slip over the spigots..

 So it would be a problem on stock length manifold rubbers as the wall is much thinner. I alway ran stockcarbs/pods without bracing, you could not do that with thinner hose, also the thinner hose , may collapse under running.

 Rad hose is probably not fuel proof.

 I did consider machining a plastic, to make what I need but would need proper durometer (to stretch), and be fuel proof..