Bike Carbs

[Guest whiz]

Hi Guys thinking of upgrading to bike carbs but which ones are the best R1, ZX6, Fireblade there is so many which ones have the best suited jets. also best place to get a manifold to fit them all replies welcome

Andy

[Guest Takumi]

Hi Guys thinking of upgrading to bike carbs but which ones are the best R1, ZX6, Fireblade there is so many which ones have the best suited jets. also best place to get a manifold to fit them all replies welcome

Andy

 

 

Bigger doesn't mean better, its best to research the size that will best suit your engine, a huge set of bike carbs will give poor low-mid range power.. a smaller set will give your better low-mid range, its all a compromise.

 

A 2L injection head, with sports cam, 4-1, will run well on 36-40mm carbs.. 36mm = better low engine speed torque, 40mm=better peak power.

 

-I have previously tried 33mm carbs and they worked very well, excellent mpg, power tailed of slightly after 6k - but the low-mid range was very good.

 

 

I'm currently using 38mm keihin carbs from a CBR900, runs very smooth.. (good mpg too) with 1.75mm mains

 

Regarding Jetting, bike carbs will be running very lean, the main jets needs to be enlarged from about ~1.4mm upto ~1.7mm'ish , once these are done, it makes fine tweaking for a smooth idle and running alot easier, they can be increased by hand with a small pin drill and the right size drill bit, 1.75 I think is tapping size for M2.2 coarse.. I think its easier to find imperial size drill bits for jetting..

 

 

 

-tak

Edited April 20, 2010 by Takumi

[Guest loopyonion]

Just as a point, internal bores of carbs can be compensated for by ram pipes being made longer. The longer they can be made, given underbonnet space, the more response and low/mid power can be delivered.

[speedtripledan]

Just to confuse the situation i also use fireblade carbs but mine are jetted to 1.3mm with blanked off air correctors, all set up on the dyno. loads of bottom end and revs its nuts off. manifold wise i use the GBS one for the price it is good