Updating the 86-87 VFR750 Dash and Clocks to a Newer VFR Style

I'd like to swap in a 90-97 VFR dash on my 86 bike, so I did a bit of research.

Here is the 86-87 regular style:



Here is the 86-87 F2 style:



Here is the 88-89 style:



Here is the 90-93 style:





Here is the 94-97 style:

 

Fuel Gauge
The 86/87 bikes only had the fuel low light sensor that made a light come on. The 88/89 bikes did not have this, instead they had a fuel level sending unit to work a gauge.

If you want to swap in a 90-93 vfr dash, it would be easiest to leave the gauge non functional and hook the low fuel light to the side stand bulb. The 86/87 don't have side stand switches, so why not take advantage of that indicator light?

If you want to swap in a 94-97 dash, they have both the light and the gauge.

If you wanted to make the gauge work, the 88-89 bikes have a fuel level sending unit to operate the gauge. It appears to bolt into the same location on the 86-87 gas tanks. Here are some pics, notice that the bases look identical.

86/87 low fuel light sensor:



88/89 fuel gauge sending unit:


By swapping to the 88/89 sending unit you'll loose the low fuel light, though. It may be possible to add the 86/87 low fuel light sensor to the 88/89 sending unit. You need to drill a hole through the lower base and rivet some plastic pieces on each side to seal the hole and allow an insulated path through the rivet. Them you'll have a 3 wire hook up. See the additional wire on the second pic below. It's a 94-97 sending unit which has both a light and a gauge.





I'm pretty sure the fuel sender will have the same voltage range as the 90-97 gauges. It's unlikely Honda changed it.

Speedo Drive
The 90-93 bikes had a mechanical speedo and it is a direct swap. The wheel speedo drive should hook right up. If you want to swap in a 94-97 dash, you'll need to convert a 90-97 front sprocket cover (I've already done) and then mount a 93-97 electronic drive unit. Then you can use a speedo healer and run whatever tire/sprocket combo you want and always have an accurate speedo. (That's my goal)

Water Temp
The water temperature sending unit is the same part number from 86-97, so that is a direct swap. No problem there.



Tach
The tach is a bit more complicated. I think the 86 bike puts out half as many pulses from the ignition box as the 87-89 bikes. I remember people doing 87-89 motors into the 86 and the tach read half the rpm's it should have. The tach just needs a pulsed signal.

I think all you'd need is to hook up the tach signal wire and see if it's accurate or not. If it reads half the rpm's it should, then you need a simple pulse multiplier/divider. Something like this:


It's like $50 USD and has dip switches that let you set the multiplier or divider you desire.
Anyway, I hope that helps anyone else looking to do a swap.

If anyone has more info, please contribute. Thanks.