sleazyrider

Hey guys, here's the deal. Ive got a 1981 honda cb750k and its time to replace some sprockets. The stock sprockets are an 18 tooth front and a 46 tooth rear and i'd like to change it up a bit so the rpm's arent so high at cruising speeds. If anyone has any tips or any experience in swapping sprockets your help would be appreciated.

thanks

MSchu

either increasing the number of front sprocket teeth or reducing the number of rear sprocket teeth will cause a drop in RPM's across the entire range. it will also make it more difficult for the power plant to rev by taxing that engine more heavily.

Making a move (up or down) on the front is a LARGER move in ratio per tooth than making a move(up or down) on the rear. You may in fact move UP on one and Down on the other to get to an overlap area where you might not otherwise be able to by changing one sprocket.

think of changing the front sprocket as your Final Drive, and the rear is the fine tuning of a gear ratio.

If your looking for a slight revision to your rpm's go down on the rear a few teeth, or up one in front. For ultimate tunablility, get a range of rears and a couple fronts.

sleazyrider

Thanks for the info. I'm leaning towards dropping a few teeth on the rear sprocket and leaving the stock front. Will i have to take any links out of the chain? or will my speedo/ tach be affected??

MSchu

unless you change the rim or tire size, there is no speedo effect as that is read off the front rim... the effect on the tach will be that it will read lower because you are spinning the engine lower to achieve the same mph... again, this requires more torque from your engine which means slower acceleration.

you may have to link your chain if you are out of adjustment on the rear swingarm.

sleazyrider

Thanks.. Does anyone have any experience with changing sprockets on these old bikes? Any tips or tricks?