Hi I'm new to your site but have been recommended by an existing using to ask here.

I've just complete by build on a mk1 golf and fitted a 2.0l 9a 16v running GSXR 600 carbs.

I want to get everything set up and running sweet.

Does anyone have any suggestions on jet sizes that I should be using?

Hope you can help?

Cheers

Ross

I'd start at 1.6mm main jets and see how you go with them, you might well need 1.7 but best to start with the smaller one so you can drill it out and go larger if need be.

Without a wideband it's guesswork, but as starter for ten the main jets in my ZX6R carbs on a zetec 2.0 are 1.6mm.

Stu

Cheers for the quick reply

I don't have a wideband sensor so i will try with a 1.6 to start with.

How will I know when it will be at optimum size?

Cheers

To be fair you really only want to get it drivable and revving freely. Once you get it driving OK you really need to take it to a rolling road place that is familiar with bike carbs and get a gas analyser in the exhaust and then have the car put though all the various load conditions to see if you are getting correct fuelling at all times.

Bike carbs have an idle jet, a metering needle for mid throttle and a main jet for full throttle. Which is why they are so smooth compared to a fixed choke set of twin carbs. They need that bit more setting up though but once done they stay in tune well.

As said you can always buy a wideband AFR kit and use that yourself to see how your fuelling is.