I just bought a 90 cbr600, replaced the head, mounted the carbs, and tried to start. blub blub blub pop! I'm getting backfire from the exhaust and out the carbs. After awhile of trying to start I finally look at my feet and see a bunch of fuel leaking. I look all throughout and see that the fuel is leaking where the fuel goes into the carbs, the fuel rail I think. After further analysis the carbs are not fitting together tight enough and the T's are not setting into the carbs all the way. I can push the carbs together and the leaking stops. But I have no idea of how to tighten them. The only bracket I see holding them all together is up closer to the front ontop of the carbs. So I took the carbs out and started cleaning them I also checked the O-rings and there fine. Any ideas?

 

Even though your o-rings look fine, they can still have flat spots on them or they could have shrunk. Both of my cbr 600s (87 and 90) have had this problem. Just spend a dollar or two and buy new o-rings. Your problem will go away.

 

New O-rings
Try www.mrcycles.com

 

Did new o-rings fix your problem?

I hate un-finished threads, hehheh.

 

Yup I got it fixed I took the carb apart and clamped them together and then retightened them and worked like a charm. I got the bike running strong and can drive it everyday. Thanks for the help everyone!