ideal carb size for a stage4 GP and RS pipe

[Davidsquaredson]

Hey,
a friend has a stock GP engine and carb, but added a scootrs expansion chamber exhaust. He wants more performance primarily for in town use and period light touring (max 100 kmph) . So low to mid range torque. I think a clubman would be a better pipe but he's already bought the scootrs exhaust.

I've got a stage 4 tuned jet200 barrel I'm not using so was going to offer to him. What size Dellorto carb would ideally pair with this. Assume using a bellows and remote foam filter.

tx in advance
David

[Norrie Bodge]

26mm delly would be ideal IMO

[Davidsquaredson]

thanks!
I have a 28mm in my set up and I thought it was too much carb for this . Was thinking it would be 24 or 26, was waiting to see what someone with experience would say.

Cheers
David

[shocky]

Why not a 22mm im hitting 100kpm with my stg4 and clubman it pretty much flat lines after that though as I was expecting a genuine 70 mph

[shaunmc]

I'm using a 26mm delly on Stage 4 with a scorpion exhaust no filter changed from 30mm. Really happy how it performs.

[corrado]

primarily for in town use and period light touring (max 100 kmph) . So low to mid range torque. I think a clubman would be a better pipe but he's already bought the scootrs exhaust.

I think you're right too.

[Strummer10]

Must admit my GP 200 stage 4 with a 22mm standard carb and scoots rs expansion flies and is as quick off the mark as mate's TS1 and gives it a run for it's money.......but I have decided to put a 30mm delorto on it with breathe easy and see how it goes after

[vespanic]

You might find his Indian barrel is stage 4 tuned. Most of the barrels in the last few years have been stage 4 tuned as a standard.

[gaz_powell]

The standard Indian SIL barrels are very loosely stage 4 - they are not like a hand attended to stage 4 where ports are cleaned/polished/edges along with manifold matching.
There is a bit of a difference.

Back to the original plot I like the 26mm not long changed a 30 for one for a mate and it's much better. On a factory 200 SIL barrel with a bit of tidying up and manifold matching..