Cams and mpg

Is there one part of the cam spec that decreases your fuel mileage in particular or is it a combination of factors assuming the no other mods are made and no changes to riding style? The reason I ask is my Andrews 27 bike with 495 lift gets 50 mpg, my Andrews 37 bike with 510 lift gets 47 mpg but my SE255 bike with 550 lift gets 20 something mpg. Common sense would tell me the higher the lift, the lower the mpg. Am I right or wrong? Would switching to a Woods Tw6 with a "mild" 510 lift increase my mpg (forget about where the torque curve comes in for now) Thanks for your help!!!

lift opens the valves more duration plus or minus keeps em open longer or shorter overlap and timing along with the lift and duration give you the power or MPG ! You can have them both

I have one motor with a longer duration exhaust lobe and this motor runs about 20 degrees cooler then the other bikes! You can get a gas milage cam ground...but the power will take a nose dive!

thanks 59panhead, can you explain the overlap part to me please?

Oh I know, don't even get me started, my carbed Softail Custom with the Andrews 27 has never dipped below 50. Unbelievable what those old carbs do.................

overlap means the intake cam lobe is opening or closeing as the exhaust is opening or closing so there is not a dead spot and the fuel or exhaust gets in or gets out as the motor increases in RPM all the cam grinds are thought of by way smarter people then me ! Thank God! I might be a little wrong on my explaination above but its early morning and my coffee hasnt kicked in yet

Im just glad I grew up in the Chicago area where Andrews cams and gears were developed and as a kid I used to go over there and ask quiestions all the time so I would understand Im 59 now and Im still learning!

Awesome, thanks buddy.

Oh man, that would be so cool. I'm down the road in Springfield, so I did feel good buying the cams for the other bikes from an Illinois company.

Overlap is the period when the intake and exhaust valves are open at the same time. The larger the duration numbers of the cam, the more the overlap. A typical street application where you are not running much in the high RPM ranges, you do not want a lot of overlap. A bike built to run mostly in the higher RPM ranges benefit from the overlap by the exhaust valve still being open helps to pull in the new fresh charge as the intake valve is opening. But it works against you at lower RPM's.

It would be for the 2008 Electra Glide.