My son had a VF750C, which has a detuned VFR motor in it. We spent a bunch on a K&N filter and installed it, and then read where it required the carbs to be rejetted and basically altered the breathing of the engine so much that it wouldn't run right.

My question is whether that is generally true for the CBR line or not?

Does a "high quality" filter help or hurt these bikes?

Any experiences out there? Thanks.

 

Good airfilters are always a solid investment.
It may mean you have to richen the mixture up on some models, but generally the bike will perform better with a good filter - not so much in terms of pure power, although there is some gain, but smooth and better economy.

 

Either a BMC or K&N they require tuning the a/f mixture. The stock paper filters are restrictive in comparision, so its only natural good ones will need tuning. With EFI models the ECU/PCIII can adjust for small changes n may not need tuning as bad but it always helps.

 

Ok, so how do we find out exactly what to do to the carbs for a particular filter in a particular bike? Is it just "cut and try?"

 

carbs will def need to be readjusted and in some cases rejetted.

 

See, that's the problem. I have no concept of how to "adjust" carbs. Don't recall ever hearing about an "instrument" that let you know you were doing it right. I don't really want to try to be Smokey Yunick.

Clueless in the country.