SPEEDOMETER Question ?

[Pass]

Hi, will a used R100 SPEEDOMETER (same year) work on a 1980 R65?

[Bob_Roller]

There's a green number on the face of the indicator at the bottom, my'81 R65 with 85 mph speedometer has W 1318 the numbers must match on each indicator, or the readings will be off .

[nhmaf]

+1 with Bob - it most likely will NOT work properly, the R100 bikes came with 3.0:1 or 2.92:1 final drive ratios, and the R65 bikes came with either 3.44:1 or 3.56:1 final drive ratios.   The "W1318" or "W1276" number at the bottom of your speedometer indicates it is geared for that many revolutions per mile, based upon use with whichever is the final drive gear ratio that you have on your bike.   On the plus side, the transmission from the R100 would be a drop in replacement for your R65 (they're identical) if you ever need to swap that out.

[tvrla]

No, it won't work. At least not without replacing the complete deshboard. The gauges are completely different.

But like Bob said, with the matching ratio, the speedometer cable will drive it, but you'll need the complete housing with the tach that goes with it. Also, it's doubtful the R100 had the same ratio, since it was pretty much used only on the smaller displacement bikes.