Iv just put on cbr 600 carbs on 1.3 8v no vac advance stock jets 135 . It runs great on the spot but wen I drive its like it won't rev past 4k help

How are you advancing the ignition timing?

Iv just advanced the timing by 10%

You can't just strap a set of bike carbs on a car and expect it to work properly. You can't just guess what's needed to get it to run properly. Every engine is different, carbs have to be set-up and tuned to the one they're on.

Said this time and time again, it's no different than anything else. You wouldn't take a map for a Kawasaki EFi and expect it to work on a Lupo so why do the same with carbs?

Take it to someone who knows what they're doing, before you melt a piston..

Thanks for the advice dude and I no you can't just bolt them on and except them to work fine id just like it to run better before I take it to be set up and iv got to drive 30 milles to get to a rr

Find the air jet for the emulsion tubes. You'll have to take the main jet out of a carb, blow into the hole, and feel which which air jet the air comes out of (little cluster of air jets next to the intake funnel, likely the middle one). Block that jet by wedging a matchstick into it. And with the other three carbs, too. Four matchsticks altogether. One each carb.

This will prevent the main jet getting air for emulsion, and subsequently run the carbs relatively rich. This won't harm the car for just 30 miles - running lean can kill it in just a couple of miles.

Turn pilot screws all the way in, just until they stop, then precisely 2.5 turns out. Always the same for all four. This will put them in a rough ballpark position.

Now the carbs should be in a reasonable 'limp' state to get you to a tuner.

Put the dizzy in it's normal position, you don't want it particularly advanced.

Get an AFR gauge and do some reading on this forum.

Thanks dude tbh I think my problem is a air Leek

okay but still get a AFR gauge and a good quality one with a bosch sensor.

I think with carbs they are such a vital tool.

i use a aem wideband which cost around £150

Don't bother with an AFR gauge, just go to someone who knows what they're doing.

You were also asked above how you were advancing the timing, not how much have you advanced the base timing by??