Looking for different speedo/tach for 1981 maxim xj550 speedo/tach

Hey I've got a question for those of you that would know.

I'm looking at this speedo/tach set from dime city cycles: http://www.dimecitycycles.com/2-5-chrome-w-black-face-mini-kph-speedo-w-trip-tach-kit-1-5-ratio.html

I know the tach ratio is correct, but the speedo ratio is weird. It says "*The speedometer ratio is 60kmh = 1400RPM, illuminated example is only to show the back-lighting and my not reflect the actual gauge."

Will this work on my 1981 xj550 maxim? And is 12mm the correct thread size for the speedo cable? If not, is there anything you guys can recommend that would work?

 

Sadly, getting correct mechanical speedometers is sort of a black art. I've yet to find a good way to ensure you get it right short of just using a stock speedo. If you DO find one that works, though, I'd love to know

 

As to the thread... Just measure it. I'm reasonably sure that's the right size though.

 

The correct ratio is 2240:60 mph. I'm in a professional workshop and am not going to do the conversion to metric just now.

Chacal has options (start a conversation) as does Mikesxs.net.

 

You can always go to an electric speedo. Most gauges (such as the acewell, or motogadget) come with wheel sensors and magnets which you put on the front end. Then you calibrate the size of the wheel rotation to get the exact speed. It's a little more work, but you open up a lot more doors with what gauges you can use.
Technically you can also convert the tach to electric as well by tapping into the ignition system. That's a little more complicated. I will be attempting that over the next few weeks on my build and will share my results.

 

very old thread says you can use xj650 tach and speedo

 

The metric ratio is 2330:100 kph. It's also listed as 1440:60 on occassion, at least according to: http://xjbikes.com/forums/threads/speedometer-and-tachometer-ratios-once-and-for-all.38405/

The tricky part (and hence my "dark art" comment above) is that most aftermarket gauges don't actually specify what they are. For example, MikesXS lists many of theirs as 2:1 for Yamaha 650's, and presumably those still work? Such as:

Also:

It seems most mechanical speedos for bikes from this period use the same ratio - I've spent a lot of time looking around, and they all seem pretty consistently at that when the ratio is shown at all.

 

Most all Japanese bikes from the era do use the same speedometer drive ratio. IIRC the XS650 was one of the exceptions. Mikes does (or used to ) have speedometers that are listed as having the 2240:60 MPH ratio.

Thank you for the link to the metric conversion. I was (ironically) too busy learning more math teaching methods to do any math.

 

So, 60:1400 will work for your 550.

 

Awesome! I really appreciate the help guys. I like those gauges, nice and small and simple.

Frank