LCGB Forums

I've recently acquired a S1 which was using a flip-up choke. I've tried fitting the normal choke, but the choke piston doesn't travel more than a few mm and doesn't open inside the carb. I'm using a PHBH carb.

I've been using a thumb choke on my S3 and GP for years and I can't figure out what the issue is.

I cured that by fitting an adjustable choke cable. I got mine from Chiselspeed.

Rich'

Is the choke lever in the frame working ok sometimes they wear ?

If you are wanting to use standard choke mechanism and the phbh ive always found you need modify the cable, by reducing the outer to get more lift, a bit of filing on the
cable end can allow the cable through the outer.
Then the venhill adjustable came out or see if Martin Knowledge Leach is still making the bespoke ones which fit perfect with a phbh.
The venhill adjustable is a big piece of kit and can be difficult to route

I regularly seem to be reworking throttle and choke cables. Venhill sell brass ferrules for pennies which you can solder on to the cable when you have decided on the right length. I also got some top hats from them so you can mate wider cable outers into smaller openings.

I use the sharp end of digital calipers to put into the carb body to see how many millimetres the choke plunger has to drop to seal. On PHBH carbs, you can easily see the choke moving up and down when activated.

Thanks for the replies.

I'll have to see if I can get an adjustable one.

I could nt get a routing i was happy with using the venhill adjustable.

Storkfoot wrote:I use the sharp end of digital calipers to put into the carb body to see how many millimetres the choke plunger has to drop to seal.

This is how I do it too. You can then measure the travel of the inner cable from OFF to ON and work out if it's dropping enough to seal.

Bilko wrote:I've recently acquired a S1 which was using a flip-up choke. I've tried fitting the normal choke, but the choke piston doesn't travel more than a few mm and doesn't open inside the carb. I'm using a PHBH carb.

I've been using a thumb choke on my S3 and GP for years and I can't figure out what the issue is.

If you are looking for a thumb choke that wont look out of place on your S1, these are excellent https://www.venhill.co.uk/controls-amp- ... 50100.html

I, been using one on my S3 for a few years and it work better than the DT one on my other scoot because it works on a little rack & pinion so it does slip back. You will need to solder your own cable though, Pail's already mentioned Venhills cables and fittings

Thanks for the new replies.

I dug out another choke lever and found it had more travel. So it’s now working.

Colin I have one of those. I think I bought it on your recommendation about 10-12 years ago but never got round to fitting it.