Ok so i just bought a 94 cbr 600 that tboned a car, frames untouchdd and mechamiclly shes ok other then those cylinders. and mainly the damage was the plastic is trash and the front forks are done for. When i bought it it had those 2 dead cylinders. Just to know what i bought i took the heads off and did a leakfown test. She looks 100% so i put her back together and she has 120 Compression in each cylinder. I tested all the plugs on the frame to see the spark and they were weak so i got new plugs. Once i put the new plugs in she ran on all 4 and sounded perfect and badass. Next thing i know 30 min later shes back to 2 cylinders and gas seems to be leaking from the o rings where the fuel connects on the left side of the carb. The good side. Or at least that area. I cleaned the carbs and same issue. I need second opinions

 

Hi , almost sounds like fuel starvation to 3 and 4, have you tried looking at 3&4 spark plugs to see if their wet or dry after trying to start,are the associated pipe's (air and Petrol) clear, and I'm assuming your's is an F2

 

Just pulled the plugs, both were dark and wet and I put them in brand new so they are getting fuel. Fixed the gas leak it seemed to be just the seeping out the float bowl gasket. I tested each plug on the frame and each has a good spark. And I know its getting fuel. I also just cleaned out the carbs with no change. Compression, fuel, spark. Stumped. also I am so confused how I got it to run on all 4 just for a little while by changing the plugs, the wires are on there well and have a good connection to the coils.

Any ideas guys common lol

 

The bike did sit for about 6 months and the guy swore the motor ran just fine before

 

Hi evidently your getting fuel to those two cylinders, you also got a spark, maybe your getting too much fuel to those two cylinders, best thing i can suggest is to take the carbs off and see if you can get it to run on those two cylinders by squirting carb cleaner into the intakes, still could be the carbs

 

Thank you for the opinion, I also thought that but I am not sure how to lean out just 2 of the carburetors. I tested the carbs by taking all the float bowls off and tipping it very slowly and that all keep the same angle

 

I just reved the hell out of it and all 4 lit up for a little bit. I think this bike just needs to be ran once the forks come in the mail

 

Hi , have the mixture screws been adjusted, or are they capped, by the looks of it your in the US ( I'm in UK) they should be set at 2 to 2 1/2 turns out from seated, but if their capped , then their at factory specs
https://cbrforum.com/forum/general-t...estion-129989/

 

They are capped. This battery seems weak. Maybe causing a weak spark. Picking up a new battery tomorrow

 

Cylinder 2 and 3 are controlled by the same coil I think..