What carb rubbers to use with Mikuni RS 34?

[arcticXS]

Hi!
I have a set of RS34s from Topham in Germany on my 1977 standard. Topham could not supply the rubbers, but indicated that OEM intake rubbers from the later models would work. I took that as any intake for BS36 would be fine, and ordered a set from JBM industries. These seemed a bit "loose" but I installed them anyway, as the hose clamp seemed to compress the rubber enough.
I have not run the bike with these carbs yet, but have looked into the issue a bit more.
The JBM rubbers have a 42mm ID, RS34 and VM34 carbs both have 40 mm spigots, according to info from Sudco.
If this is correct, where could I get 40 mm rubbers, with the correct angle for an XS?
As a lot of you guys must be running VM34s, there surely must be some intake rubbers on the market?

 

[grizld1]

I'd have sworn that RS34 and RS36 carbs had the same spigot OD, but a quick look at the manual showed that you're right--RS34 has the same 40 mm. OD as the VM34.

Like you, I'd feel uncomfortable about using boots made for carbs (BS34) with a 2 mm. larger spigot; but I'd also feel uncomfortable about using anything else than a JBM boot without additional support for the carbs. If I were you, I'd fire up with the JBM's and test for leaks. If they don't work for you, Michael Morse at 650 Central offers premium rubber boots for VM34's.