[Lunatic]

The bolts for the header flanges to cylinder head were in poor shape. They were rusted, missing and ugly.
A trip down the fastener isle led me to these. Stainless steel, hex socket cap screws, M8x1.25x25. Installed using copper anti-seize compound of course.


The stock 750 lower oil cooler support brackets almost fit. Due to the taller height of the 1200 engine, these required a little modification. I flattened them out a little to space them away from the header tubes. By doing so, I then had to machine four little spacers to go between the chassis down tube and oil cooler brackets. They were 13mm (1/2") wide.


Here's the 750 oil cooler properly installed and secured. One more thing checked off the to do list.

[Lunatic]

There are three electrical items that I still need to address; the tachometer, speedometer and the fuel sending unit. Today, I'm going to focus on the fuel sending unit.
As you've seen, I installed a 6th generation Honda VFR800 instrument cluster onto my Katana. For those that are wondering, they don't actually play well together. They, (Honda vs Suzuki), use slightly different ohm ranges in their sending units. In saying this, if I'd plug them in as is, the fuel gauge would be off. This is not acceptable and I want correct fuel gauge readings.

For those interested, here are the specific ranges:
1988 Suzuki Katana, 12 Ω (ohms) full and 131 Ω (ohms) empty.
2002 Honda VFR800 1-5 Ω (ohms) full and 92-96 Ω (ohms) empty.

I looked at Ohm's law and tried a few calculations. I was hoping to find a result that would allow me to add resistance, via a resistor, into the circuit. While I got the low level (empty) spot on, the upper range (full) was too far off for my liking. Time for plan B.

Plan B was to take the stock VFR sending unit and modify it to fit into the Katana's fuel tank. Here's how I did this.

In this photo, you can see the stock Katana sending unit.


Here is the stock VFR sending unit.


While both are obviously different, I now need to chop, cut and rebuild both of them to make one that works. Frankenstein...

During this process, I had to contend with the range of sweep as well. The Katana had a float sweep of around 45° while the VFR had around 75-80°. I had to keep this in mind during the planning stages. Taking some measurements inside the fuel tank, which wasn't a lot of fun, I had the information that I needed. It seemed doable but I had to place the float in the exact place in order to make this all work.

Onto the mods.
I cut the VFR bracket off the VFR sending unit. I also cut off the Katana braket off leaving around 3/4" showing. I then tried several configurations to give me the best fit.
This gave me the best result. The VFR (gold) bracket TIG welded onto the Katana sending unit base.
While it does aim up slightly, this was done so that it would clear the opening.


Here's the VFR float assembly installed.


It didn't quite fit in the opening as the square edge was hitting. After rounding the corner, this now fits.


Here's a photo of the wiring attached.


In order for all of this to work, I had to do the following.
Flip the float arm around 180° and use the Katana float bobber as it was slightly thinner.
This was necessary in order to give a proper range (sweep) of travel from full to empty.


In the end, the float sits on the hump inside the tank. This is the not the lowest point in the tank, however, when the fuel gauge reads empty, there is still a little bit of fuel left. Not much mind you, just a little.








And there you have it. I now have a working fuel gauge. I also like the fact that fuel gauge starts to flash when approaching the empty mark. Just something to get your attention and let you know that you're in need of fuel.

[Lunatic]

A little more information to add as I move along.
Due to the taller height of the B12 engine, the fuel tank petcock hits the number one carburetor top cover. I found this out when I tried to install the fuel tank this morning. The rear mounting point gap is too large and I didn't want to damage the perfect fuel petcock.


My solution, of course, was to machine some simple spacers. I made these 8.4mm (.300") tall and I used aluminum.


Here you can see the spacers installed and the needed clearance they provide. Even with this minor elevated change, the seat still fits and the gap seems acceptable.


I then installed all new fuel lines for piece of mind. The original ones were over 20 years old. Yikes!