Hey, so i have cbr 600f2. And i was just wondering what would cuse poor gas mileage. I was told i would get around 45 mpg. But i filled up with 91, 2 days ago drove 140 miles exactly, and with four gallong tank thats 35 mpg. So i flipped it to reserve, and well i guess my reserve dosnt work ha. But i was just wondering wat would cause a 10 mpg decrease? Thanks!

 

anything from dirty airfilters, fuel filters, carbs, tire pressure not right, any of these things could reduce your mpg. are all of your fairing secure, because if not they will cause excessive wind resistance and raise your cbr's fuels consumption.

 

does it require 91? If it runs on 87 then it may not be combusting properly.

 

it dosnt say anything about requiring 91. I have just been buying 91. Should i buy some 87?

 

Run what it needs. If it requires 87 and you're running 91, you're just pissing money away. Your engine doesnt need the higher octane so it may not be burning it completely.


Again check to see what it needs.

 

jst checked the manual.. it dosnt specify. Would it be on the bike?

 

Its got to be in the manual. What year is your bike?

 

You just re installed your idle adjustment screw. Did you do it right? Is it possible you messed up your idle setting? I think i read a post where you set it at 1800 rpms. That is slightly too high for any bike that runs on gasoline. it may even be possible you put your throttle bodies out of sync, or they may just need to be synced as regular maintenance. check everything like sealik said. air filter tire pressure plugs and carbs. carbuerated engines require more attention to detail when it comes to fueling. no computer to help accomodate for small changes in air or fuel volumes that can change due to dirty filters or clogged lines, or high alttitudes etc. not an expert, just letting you know you should check the basics, besides, geting 45mpg isn't easywithout riding somewhat conservatively. so if you are trying wheelies or racing between stop lights, and maybe even shifting in the high rpms, forget 45mpg. cause that shouldn't matter!!! ha ha ha ha ah