Best Carb upgrade for GP200 Stage 4

[paulnobodyimportant]

3 of my scooters are all with tuned engines, but my GP200 is standard. Its an Italian GP200 with original gearing, 22 Dellorto with an external filter and a SIL proper stage 4 top end. The exhaust is a CamLam ancillotti. The engine is super smooth, but on scooter runs with others, it lags behind a bit. So could do with another 5mph, but not at the expense of dropping down to a TS1 fuel consumption.

In my spares, I have a 26, 28 and a 30 Dellorto PHBH, so which is the best one to use out and run it through an external filter.

Thanks

Paul

[Muttley McLadd]

Who did the stage 4?
A good stage 4 with a 30 mil carb should be reasonably pokey.

[paulnobodyimportant]

I bought the top end of someone else who had it tuned by Chiselspeed who I Know to be good with tuning.

[Andy W]

I run a 28mm PHBH and Taffy copy exhaust on my untuned St4 top end and it runs and pulls well and it reurns 20+ to the litre, and goes quite well for a std barrel.

[Muppet]

what? how? is it possible?

[grimspeed]

Id look at a 26 mm Mikuni !

[Doom Patrol]

Why don't you look into different gearing? Different carb or not it's still going to be limited by the gearbox.

[corrado]

Why don't you look into different gearing? Different carb or not it's still going to be limited by the gearbox.

It may struggle on inclines if you go taller on the gearing.
Mikuni TM24 would be my choice.