So ya all season I've been tuning this 1k dollar bike and I'm pretty close except for it sounds like it's running off 3 cylinders from 1 to 4 thousand rpm which means it's really hard to do anysort of clutch wheelies. Today it was like 75 out colder than it had been like 90-95 and she ran Amazing, I was able to pull it up no problem and expierence smashing my nuts on the tank for the first time lol. Anyways I'm trying to figure out why she runs so well only when it's cold out?

 

I would think it would be an issue with the tuning of the carbs. If it is carbed for a different altitude / tempatrure range that could cause the issues, or if it just isn't tuned at all. I would start by checking the plugs.

 

^^^ there all brand new plugs what it is most likely is the carb boots expanding when it's warm creating a vacuum leak

 

well I could be wrong here, but what about the grade of fuel you are using?
the colder gasoline is - the better anything runs :P. And well ****ty gas will get you ****ty results. What grade do you use?

 

93

 

sounds like your carbs are out of sync, or you need a tuneup.

 

F2's don't need 93 octane. 87 is more than enough. There's a whole thread some where concerning the conversion of RON numbers.

I'd first go with tuning up the carbs. Seems to be a default answer for me.

 

Id say that the carbs need to be adjusted. More than likely you have at least one that is running rich. The cold air is more dense and it provides a better or more optimal mixture ratio for the combustion. Mine used to be tuned rich. you could smell the exhaust and tell when it was warm out, but when it got into the 50's and 60s here, look out, it ran great. now going to pay someone to tune it properly again.