Carb size

[jon]

Can’t remember posting here? But seems the most on topic.

What are you guys using in terms of carb sizes?

I’m doing a Mike Abbey tuned 385cc for bottom/mid range power.

I’m led to believe bigger carbs for top end power, and smaller for bottom?

My heart says after many years around 2 strokes (mainly tuned lambrettas) that a 30mm carb is the best choice for the cc of each barrel?

Trouble is I favour the Keihin PWK and I can’t see a genuine Keihin in that size.

So there seems to be a massive jump from 28mm PWK to 33mm PWK on Norbo’s Shop.

TMX 30mm looks good but I’m not a fan of powerjet, especially on this size of carb. Thought it was only necessary on 34mm or above?

What are people running?

Jon

[midlifecrisisrd]

Pwk 28's on my 385

Mid range stonk 😁

Be careful, I've heard of 385's not being happy pootling around. Maybe carbs?

Steve

[Robbieben]

A 28 mm carb is good for up to a 250cc cylinder, especially if you are looking for midrange. 30 would offer more top end. In many cases the carbs aren't the problem, the restrictions are in the air filters being able to flow fast enough to support the carbs.

[bare]

28MM Keihins "fit' Easily.
Bigger carbs foul the clutch activation contraption. So one then needs to mount the bigger carbs askew in the inlet rubbers
(primitive but works, also looks shit)
OR buy and fit Billet /bespoke inlet manifolds: $$$

[marrcel]

The max size on stock rubber inlets is pwk30. I run chinese copies

[lowlight]

Jun 6, 2021 11:31:57 GMT 1 marrcel said:

The max size on stock rubber inlets is pwk30. I run chinese copies

How do the copies run?  Any odd behavior?  Was setup reasonable?

thx
Sean

[Tobyjugs]

Last week i saw 38 mm copy Mikuni's making 79 PK on a RGV 250 engine. The owner wasnt satisfied with this and bought a genuine set. The maximum output was the same 79 PK, but the midrange and pickup was better. The fake carbs was fitted with genuine Mikuni jets and also used the fake slide.