How’s that for a surprise! I’m back after all this time! I’ve not had much time to do anything on my Guzzis mainly because I’ve been occupied with the BSA and my friend’s Le Mans which still isn’t done.
Earlier this year I bought a speedometer from a Guzzi 1000G5 or i-convert (I think) as a replacement for the characterful original fitted to The Fire Bike, my V7 700. As you can see, this had become fairly tatty inside as the numbers began to peel off the dial. This could be fixed with an overhaul but it only shows km/h anyway. I added the MH markers. It’s also very inaccurate registering 25% under, showing 40 for a true 30MPH.
Fitting the new unit would need a little bit of work as it doesn’t have the warning lights mounted in it as the original does. I would have to make a new light console and mount these above the new speedo. I knew there would be other challenges as well. This is the sort I bought.
To make a start I disconnected the battery then removed the binacle containing the speedometer along with my home-made switch/light panel. To recap, this houses my lights switch (pilot light only to the left and pilot lights plus headlamp to the right), repeater lamps for high beam and turn indicators, and my sparkbright battery condition light.
There are only four screws holding it to the fork yoke and with the binacle raised a bit you can get behind to disconnect the speedometer drive. I unscrewed the lock ring and flap for the ignition switch, pushed it inside, and then was able to hinge the hole lot upward to make a note of all the wiring connections.
The connections on the back of the speedometer itself were;
- White – instrument back light.
Then the four lights in a row.
- Yellow/black – lights on.
- Red – dynamo.
- Green – neutral.
- Grey (looks white in the photo) – oil.
and beside those
- White/black – this is a common wire for the dynamo, neutral and oil lights.
I didn’t disturb the wiring to the ignition switch but disconnected everything else so that I could transfer it to the bench. Once there, I stripped the old speedo out of the binacle and set my switch/light panel to one side. I offered up the replacement speedometer and had a think about how to hold it in place. I ended up shortening the fixing clamps which came with the new speedo after trying to work out the depth I would need. It worked.
I forgot to say that I had removed the trip reset cable from the back of the new speedo for now. I needed to think about how best to get it out of the binacle to some form of bracket outside.
In the meantime I designed my new switch/warning light panel. I had bought some LEDs to perform the necessary functions. These are much smaller than the units used before as now there will be 5 plus the battery condition light. I’m not going to have a “lights on” warning as I think that’s pretty redundant. The battery light can also be reduced in size by removing its bezel and sticking it to the panel. I had decided to fit a switch to isolate it so I can wire it direct to the battery. At the moment there’s quite a voltage drop when it’s fed via the ignition switch.
A card version of the new layout was made first.
Then the holes cut out of the last piece of aluminium angle in my off-cuts box.
Happy with this I could now cut it down to size but, then I had a thought. If I drill a small hole in the back of the speedo binacle I can get the trip reset knob to the panel as well. I spent a very long time considering whether I should do this to an original part before deciding that I would. Then even longer trying to work out exactly where that hole needed to be and how to add the reset knob to the new arrangement. When I did take the plunge it worked out well and the cable was refitted. It’s held to the speedo with a tiny screw.
Now I could cut the outline of the panel,
tidy it up and bolt it to the binacle. If you’re wondering about the numbers, they’re the tyre pressures I run – front, rear and trailer wheels.
All that was needed now was to wire everything up. I needed to bring the wires for the dynamo, neutral and oil lights out from behind the binacle. Luckily there was enough room to unplug the bulb holders and extend the wires so they could be fed out through the top fork yoke and around. This meant I didn’t need to drill another hole.
The unused yellow/black cable was insulated and tied out of the way.
All that remained was to;
- Change the terminals on the cables for main beam and turn signal warning lights.
- Refit the lighting switch.
- Refit the battery condition light with it’s switch in line.
and that was the wiring finished. The ignition switch was persuaded back into position and the speedo cable done up. I’m pleased with the result. There’s enough space under the warning lights for me to stamp a letter for G(en), N(eutral) and O(il) if I decide to but I’ll probably not bother.
Battery connected and everything works. The next day I took it for a short ride to compare the new speedometer output with that of the push-bike speedo I fitted when I realised the old speedo told lies. It turns out that this new speedometer is really accurate and the push-bike one can go. I quite like the look and apparently, if you scrape the black paint off the bezel, there’s a nickel finish beneath.