8 replies to this topic

[087dave]

Hi all, i am putting together a set 1.25 twin carbs and wondering
how many springs to put on 2 or 3, is there springs for the accelator return
and is there a spring for the choke

Thanks in advance!!!

[mars red mike]

I seem to remember that my old twins had three springs on.

[samsfern]

not sure about choke, but there should be 3 throttle return springs.

[surfblue63]

I've seen set ups with various numbers of springs, but three is the norm. It all depends on how much feel you want in the peddle.

[cooperrodeo]

The choke return spring is integral with each carb. Each throttle has a return spring and there is an additional one for the cable. I never bother with this third one as the two throttle ones provide adequate control of the throttles and make the pedal the right weight.

[partsguy1]

^^^^^Agreed^^^^^^^

The only problem that I found was if using two springs only, your throttle cable can't have any binding or you will find that your idle speed will vary on the high side, blipping the throttle when coasting to a stop can make the idle settle down. The weight of throttle peddle can cause this effect as well, I have a Hopkirk extender that really made things interesting. Just my experience.

[Spitz]

How much was that extender terry?

[087dave]

Thanks but is there a clip for the choke cable to keep it in place like
the HS4 carb

[cooperrodeo]

I certainly agree you need a smooth operating throttle cable but if you haven't got one I'm not sure that the third spring will help. This is because if the throttle won't close smoothly without a third spring it is unlikely to open smoothly with the spring. If your throttle cable is sticky then bicycle brake cable is the way to go as the cable runs in a liner.