2in1 Harley Tach/Speedo, will work it work on an XS?

poorman9

poorman9

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They call it a - 2:1 Speedometer with Tach for 1981-1990 Harley FX-FL Big Twin


It's 2:1 ratio, so that should be fine, but I'm not sure about the drive cables. Any harley guys care to comment? I don't mind fabbing up mounts for it, but anything beyond that might be too much of a hassel.

Thanks!
 
Looking at the back of it, I'd guess that the tach drive is electrical instead of mechanical.
 
You might be able to hook the tach to the coil and have it display something... Some electric tachs have a switch inside you can play with to try to get it to read right for your bike...
 
The question would be does Harley use a "waste spark" coil? if so the tack should work (they are both 2cyl bikes) Tachometers are calibrated for the number of cylinders
 
Alright, I've got a 81 with a Boyer blue box ignition, which I'm guessing produces one ignition pulse per rpm, and I'd some how want to wire into that?
 
Even though I have been turning wrenches on automobiles for over 20 years and tinkering on bikes and snowmobiles even longer, I have never wired in a tachometer :laugh: I have used test tach's that have clips and they just clip to the coil ... I assume wiring one permanently would be the same.
 
My parts guy said Hogs runs a different ratio than the Japanese stuff... Jap speedos (cable driven) should swap around. The tach should work if its a inductive pickup type.
 
Some HD coils are 2-1 ratio, and some are 1-1. I think you might have an issue with where the cable threads on to the speedo. And, all HD's are of the wasted spark type of ignition except some aftermarket ign's and all of the twin cam motors (1999 & newer). The tach should be no problem.
 
Thanks guys, after quite a bit more searching I found they make this speedo/tach in a 2:1 an 1:1 ratio which I'm guessing is the ratios of the speedo. I'd obviously want the 2:1.

And this catalog mentions that it "features a built in electric tachometer for 1978-1990 FX-FL models with operate tach from coil impulse." So xjwmx I'm guessing this wouldn't have a switch inside for the tach.

So if I can verify that the ignition system emits two pulses per revolution of these FX-FL Harley's then that tells me if the electric tach will work on my XS. And I see Mikes sells several different electric tachs, but I haven't found any install instructions.

Does "wasted spark type of ignition" tell me something about how many pulses per revolutions?
 
I just found a bit more information about it -

Pulled from ebay -
"The speedometer is a 2:1 ratio and has a 5/8"- 18 cable fitting. Does not have automatic turn signal cancel capability. Tach is electronic and reads RPM from 12 volt coil output. Single fire ignitions require tach adapter not included."


So....?
 
I would find out how many pulses a Harley coil sees per crank rev, and see if it's the same as your bike. If not then I would look into that adapter and see what it does.
 
Harley FX and FL shovels from the 70s fire each plug twice per crank revolution. Each time the piston reaches top dead center the plugs fire. That and their unusual firing order is the reason for the unique sound.

So I'm guessing the tach should work.

Speedometer might require a special cable be made up with Yamaha fittings on the bottom and Harley fittings at the top. I would think most automotive speedometer shops should be able to do this at about $80 per hour.
 
Thanks ReycleBill, I'll make some phone call's tomorrow. If I end up ordering it and getting it working, I'll post my results here.
 
Hey anybody from the future that might be wondering what happened with this, here's an update -

I got the gauge and my stock speedo cable and took it down to a speedometer shop here in Portland (yeah apparently there are shops that only work on speedometers) for $20 they made me a 3ft cable, standard end on the wheel side and some bigger (but common) size on the other. I built a little bracket and mounted it up.

I still don't know if it read the correct speed, find that out when I get the bike running. And the tach still isn't wired up, it is electronic, and I'm guessing I'm gonna wire it to the coil somehow, but I've gotta get the bike running before I can test it.

More updates to follow.
 
poorman9 said:
Hey anybody from the future that might be wondering what happened with this, here's an update -

I got the gauge and my stock speedo cable and took it down to a speedometer shop here in Portland (yeah apparently there are shops that only work on speedometers) for $20 they made me a 3ft cable, standard end on the wheel side and some bigger (but common) size on the other. I built a little bracket and mounted it up.

I still don't know if it read the correct speed, find that out when I get the bike running. And the tach still isn't wired up, it is electronic, and I'm guessing I'm gonna wire it to the coil somehow, but I've gotta get the bike running before I can test it.

More updates to follow.
Click to expand...

Great price! The local speedometer shop where I live (the only one within 100 miles) won't even take on a job for less than $80.oo. There was a time when we had more options but the others got busted and shut down for falsifying speedometer reports to "fix" speeding tickets.

I think it should work out okay for you.
 
ippytattoo said:
what are the physical dimension of this speedo? I like the idea of a single gauge with both speedo and tach.
Click to expand...

I can get some measurements for you when I get home I think it was about 4 and half inches in diameter.

That being said, I would not recommend buying this gauge. I could never get the tach to work and I put 75 miles on the gauge before It broke.
 

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