Looking for aftermarket gauges for your bike? Here are the speedometer and tachometer ratios for the Honda CX500, GL500, CX650, GL650, GL400 and CX400 motorcycles.
The speedometer ratio is 2240rpm=60mph, or 1400rpm=60km/hr, or 2330rpm=100km/hr, or 2:1.
The tachometer ratio is 1:4.
These ratios aren’t relevant to digital gauges like this one on eBay US, eBay CA, eBay UK or eBay AU as they pull their signal from digital pickups (like a hall effect sensor and magnet on the front wheel for the speed) and the stock speedo gearbox/tachometer ratio does not apply.
If there’s no ratio listed for the gauges you’re looking at be sure to enquire before buying – if it isn’t the above your new gauges will not read correctly. The speedometer ratio might be advertised any number of ways, as you can see from the three options above just for that – some other advertised ratios might work out to be identical, so you may have to do some math to work out if it’s the same as the above figures.
Gauges of the incorrect ratio will often fit up but provide wrong readings – best to stick with the correct ones. In addition to eBay, you can find a bunch of options on Amazon for speedos or tachos.