Engine replaced and runs poor

[limey]

intake gasket leak

[indytiger1050]

Could be wrong but.

The body size of the carbs are not the same between the 750 and 900. (at least on CB750's and 900's there not)

You need to use a 900 carb with the 900 jets, 900 jets in a 750 carb will make the A/F ratio to rich since the air volume is reduced with smaller carbs.

[antisocial]

check to make sure your pilot jets aren't plugged. my old cb750 used to run like shit at idle unless you used the choke, turned out the pilot jets were plugged. carb cleaner did not get it, i had to run a guitar string through them as whatever it was had hardened in the jets. after unplugging the pilots, synchronizing the carbs (with merc sticks), and adjusting the pilot screws to 2.5 turns out, it was perfect.

[richardboreham]

Hello, just to let you know. I got a set of 900 carbs from Ebay. Measured them up, and they was the same siae as the 750 carbs. Fitted the 900 carbs and the bike is running sweet. I must have had a vacume leak some place. Thank you for all your input. it was much appreciated.

[limey]

intake gasket leak