TOPIC:

Just bought a 1981 KZ440 LTD, and would like to lower the RPM at hiway speed. does anybody have any thoughts ? thanks.

Gearing it up will reduce the highway RPM but it will also have a detrimental effect on acceleration, everything is a compromise you just need to decide which is more important for you

I've done this on my KZ750, but only a small change. Changing your sprocket ratio (larger at the front or smaller at the back) will do this for you. Why do you want to lower your highway RPMs? If your engine feels a bit 'buzzy' this may fix it (I believe you have a 6-speed, so could drop back to 5th if you need that extra power). Fuel economy won't necessarily improve - these engines are designed to run at higher RPM and have a decent amount of valve overlap and are inefficient at lower RPM (the i4s in particular). And as wookie noted, changing your sprocket ratio will change across all gears.

Moving up one tooth on the front sprocket makes a noticeable change and is cheap.  Make sure you have clearance at the output shaft, and realize that chain lengthening may be needed if your chain is currently on the short side.

wrote:

Just bought a 1981 KZ440 LTD, and would like to lower the RPM at hiway speed. does anybody have any thoughts ? thanks.
 

Before we get too far into the discussion, which LTD model do you have: a KZ440A (chain drive) or a KZ440D (belt drive)?

If you have chain drive, the suggestions made so far will work. Keep in mind that a countershaft adjustment of one tooth is equivalent to an opposite adjustment of 2-3 teeth on the rear sprocket. For example, going up one tooth on the front will give the same result as going down 2-3 teeth on the rear.

If you have the belt drive, you don't really have any easy options for changing the final gearing. In that case you can convert to chain drive and proceed as normal.

I dropped 4 teeth on the rear sprocket...runs about 400-500 rpm lower between 60 & 70 mph & I really can't tell much difference in acceleration but this is a commuter bike mostly & never really wind the joker up anyway.  I had to remove 1 chain link.