1982 CB750SC Nighthawk, Tack Ratio and Speedometer Ratio

[wwccll]

Hello all, I want to get new gauges for a 1982 cb750 sc nighthawk. I guess I need to know the Tack and Speedo Ratios. Does anyone have a clue?
The gauges are listed as tack, 4 to 1 and speedo is 60mph=2240rpm.

Thanks

 

[Loose Chain]

The speedo is wrong. Your bike at 60 mph would be around double that estimated rpm.

 

[brettp]

I think those ratios are correct. Honda used 2240:60 speedometers and 4:1 tachometers for most (if not all) of the '70s and for all the DOHCs.
Loose Chain is correct that at 60mph your RPMs will be higher (as are mine) but those are the correct ratios for the gauge.

 

[Loose Chain]

Okay I get what you are saying. So I wonder if it is 2:1 coming off the front wheel then, which would double the 2240 @60?

 

[wwccll]

Okay great, thanks to both of you.