Re: What sprocket ratio to use?

Posted by shinyribs on Sep 07, 2012; 4:09am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/What-sprocket-ratio-to-use-tp4028807p4028808.html

The bike I have that setup on has a 120/90-18 rear tire-pretty common size- and it cruises 70mph at 5k rpm. That bike is also a 76F which, as far as I understand, has a transmission that is geared taller than some of the earlier bikes,at least in the lower gears. All the bikes have the same 5th gear ratio.I belive your 78F should be geared very similar to my bike,internally that is. I would really have to check the FSM to be sure on that,though. 5k@70 may seem geared a but steep,but it wont pull hills with my throttle lock on,it requires more throttle input. Also,I wouldn't mind it if the bike was a little snappier in 1st gear. Im not saying I'd ever gear the bike lower than it already is,just as a reference that 18-48 is not 'dump truck gears' ,if you know what I mean.

18-48 is all I have experience with. But with the rpm range these motors like to make power in,and since I run at 60-75 mph for 80%+ of my riding,I would not care for a bike geared any higher.JMO. I just had to buy sprockets for another bike of mine and even thought it has an earlier engine(geared lower) and a smaller back tire I still went with 18-48. I'm sure others have ratios they prefer more,but for a good mix of highway and around town I like my setup.

Oh,I regularly get 42-45 mpg. I have hit 50 mpg a very few times. And I usually ride pretty hard.