VHSH rubber mount

[mawso]

Hello folks, I'm running a Dellorto 30 VHSH with Chiselspeed stepped rubber and a stubby manifold of unknown brand/make on a small block.
The carb has had the groove on the back machined wider to seat the rubber better but it still doesn't line up and the lip on the inside of the rubber is being squashed onto the flat metal of the carb spigot. The wide jubilee nearest the barrel also seems to be working against holding the rubber in place, as the screw part interferes and stops a neat flush fit.
In short the carb can be moved an turned easily by hand on the rubber and the whole thing works loose after a few miles...resulting in carb hanging off this eve. I've managed to stop a couple of times when I can hear it pinking or gasping and try and push it back into place. But coming home from putting some running in miles on the bike it dropped off. I think this rubber is the specific one for VHSH but it doesn't seem to work for me.
So can anyone put me onto what is the best trouble free rubber and stub manifold combo (for a small block) for this carb pls? I had heard the Grooves on the back of this carb isn't in the same place as PHBH's?

Thanks Stu

[sydduckett]

You can use a VW beetle carb rubber for this. I have an rb20 and so does a mate who was put onto these with the same vhsh carb, he swears by them as they are a perfect fit and cheap as chips.....

[Lambretta Sash]

I use standard 30mm carb rubbers with no ill effect to date :biggrin: . Jubilee clips will not fit cylindrically around the circumference of the rubber due to the screw part on them, leaves a small section flat. Try and get some jap bike carb clips from a bike breakers and they'll seal and hold it bootifly. May need the screw changing to M5 bolt.

Or these

The clips are also similar to the original VW type, pattern VW does'nt seem to work well.

[mawso]

Couldnt find anything that looked right when I did a search on VW rubbers, is it same as the silicone hose that some use? Was just worried weight of carb might make it sag. Not seen it up close but the carb is quite heavy at 600g and that is part of problem I've got now. When the rubber gets hot it just starts coming off.

Yep the jubilee is def part of problem too. Had thought about using a thinner one or if using flat hose I could mover a wider one back a touch without it catching on stepped divider.

Some photos might help, if I get chance later I will put some up.

Thanks.

[tavspeed]

hi stu,i used on of those stepped rubbers from chisel with my mikuni tmx 35,went to carrying on kemping,and nipped it upon the way back,the rubber had split in about 90 miles,bit the bullet and got the correct manifold and rubber off mb,not had a problem since,keep your eye on it as they dont like heavy carbs.

[Adam_Winstone]

Same old problem of location ribs being in different positions. The PHBH and VHSH have this rib grooves set at different depths, which are different again to the MK2 26mm Amal depth, with Malossi rubbers having a different depth to Dellorto rubbers (hard to get) and many of the aftermarket rubbers being different again! As the PHBH type rubbers are much easier to get hold of I ended up cutting a second groove onto the spigot of my VHSH so that getting a rubber now, and in the future, is not such a problem (not ideal for an expensive carb though!). I measured the correct depth for a PHBH, marked this in pen, then went around it with a saw blade, then worked it with a round needle file. The end result is good and I've not had any more issue with fitting problems or carb falling off, which repeatedly happened when I tried to use the no-rib cut length rubber hose mount that some people use.

I did note that the MB rubbers were about the only ones that I could find that had 30mm internal diameter, with some being less than 28mm! Well done MB

Adam

[mawso]

Sorry for late reply, been away for a few days. Thanks for the detailed answers.

After removing the carb, rubber and manifold to get a better look; it's the connection from stepped rubber to stubby manifold that's not seating properly.

The extra width machined into the groove on the spigot of the carb holds the rubber on tight enough with a narrower clip thats backed off a bit away from carb.

I've solid mount CDC manifold that used to be on and is flowed to match barrel. If the MB rubber is best fit/match, do you think if I got the MB rubber and then got the solid mount machined to down to match it, then that would give a decent lined up fit? As mentioned before the stepped rubber was meant to be for VHSH but that needed the carb machining to get that to sit anywhere near right.

Cheers Stu

[mickdale]

You can use a VW beetle carb rubber for this. I have an rb20 and so does a mate who was put onto these with the same vhsh carb, he swears by them as they are a perfect fit and cheap as chips.....

dont seem to be able to find a vw beetle carb rubber that fits the vshs
anyone know of a place to get them or a link?

any help greatly appreciated

cheers
mick

[corrado]

I think the stepped rubbers are 34mm down to 30mm, used to fit a 30mm carb PHBH or PWK on a standard TS1 inlet manifold. The VW ones are not carb rubbers, they're off a camper and think they're a suspension part.

[mickdale]

thanks corrado
ive got a 30mm inlet manifold - and 30mm vhsh
dont think its what im after then

the carb is heavy and need a quality fixing - i believe the vhsh groove is different to a phbh just to make life difficult