[Pvo22]

I've been in the process of rebuilding an 84' Nighthawk. I had to take the engine out and replace 2nd gear which was alot of fun. Now that thats taken care of I'm trying to get it to run right. As of now the 1st and 3rd cylinders are running about 100 degrees hotter than the 2nd and 4th. I've rebuilt the carbs a couple of times now and nothing has changed. I cleaned out the pet**** thinking that it was restricting fuel flow. I've checked the float height to see if they right and they are all the same. I've switched the plugs around in the 1st and 2nd cylinder to see if there was a difference. I also switched the slow and main jet around in the 1st and 2nd cylinders. I also checked for vacuum leaks between the carbs and the engine. None of this has caused the temp to go down in the 1st cylinder or go up in the 2nd. I am frustrated and stumped. What am I missing?

 

[CB750F]

They could be out of balance, one carb getting more fuel and running rich and another one getting less and running lean making it hotter than the others. Might be time to have them sync'ed up.

 

[slicknick218]

I may be off base on this one but I believe cylinders 1 and 3 share one ignition coil and 2 and four share the other coil so I would double check that you have a strong spark on the cylinders that are under temp.

 

[kclauer]

I have an '83 nighthawk 750 that won't start. Only one side of the engine gets hot. Check out my full post.