Category Archives: Electrics

ST1100 Electrics

ST1100 P1 C04 After

The first bit of electrical work I did on the bike was on the original conversion to naked form. The front fairing subframe had brackets for various relays and the ignition control unit (ICU). Having scrapped the (bent) subframe, the relays went behind the headstock, sharing space and bracket mountings with the ignition coils. The ICU went on a now-redundant subframe mounting bracket. None of this required any wiring changes, though I did pull out nearly a kilo of wire and a few relays that were not actually doing anything – probably a failed attempt at hazard warning lights. The new indicators were just connected up to the original wiring with chocolate-block connectors – one is visible as a bulge in the wire behind the horn.

With a more radical re-style, a bit more electrical surgery was needed to move components around.

For reasons best known to Honda, the indicator relay was behind the right side panel but all the wiring goes to the front of the bike, so it made sense to me to relocate it. This was just a matter of stripping the outer cover off that part of the wiring loom, putting the relay on the front of the airbox. For neatness sake I shortened the wires – just cut a chunk out of each, slipped on a short length of heat-shrink insulation, solder together.

The fuse box was to be moved from behind the back of the left side cover, to the top of the airbox, as was the ICU. In this picture the fuse box (red wires attached) is resting on top of the under-seat fuel tank on its journey north.

ST1100 P4 E06 Electrics

As you can see above, a lot of the wires were tangled round each other in the loom, necessitating more cutting and joining before the fuse box could be re-homed. Most of the wires to the fuse box come from the front of the bike and needed to be shortened, but a few come from the back and needed to be lengthened. Fortunately I have a cardboard box full of old bits of bike wiring – I can’t remember quite where or when I acquired most of it. To extend wires is the same process as shortening them, except for splicing in an extra bit, preferably of the same or similar colour, though not always possible. I prefer to keep both ends in the original colour and have a different colour in the middle if necessary. All the joints are soldered – it’s worth learning the art. I found I needed a 40 watt soldering iron to cope with the cold in the garage.

Here the wire-extending is done, wire shortening not yet done. For now, all that spare wire is wrapped round the top of the airbox, and it might stay that way for a while. It looks horribly complicated, but by dealing with one wire at a time it’s not difficult.

ST1100 P4 E08 Electrics

The fuse box actually ended up where the ICU had been, on the left of the airbox, with a vague notion that it might be more accessible there.

With the battery now further from the starter relay it needed a longer red ‘live’ lead. I un-soldered the terminals for the relay and battery connections from the original wire and soldered them onto a length cut from a set of old jump leads. It needed a blow-torch to supply enough heat. It was comforting to know that old Pan Europeans are being broken for spares all the time, just in case I lost or destroyed any vital component. The black ‘earth’ lead was already long enough.

ST1100 P4 E10 Electrics

The only other significant bit of electrical work is replacing the old warning lights with an LED panel – covered under ST1100 Lights, Clocks & Fairing

ST1100 Lights, Clocks & Fairing

ST1100 P3 X07 ed After

Part of the redesign started in 2012 was to get rid of this modified Triumph Tiger front panel. I thought it looked great when I first finished it, but now it seems to look too much like the old Avon fairings that the police and AA used on their BSAs, available today on eBay for 99p. Replacing it with an off-the-shelf supermoto/streetfighter fairing would look silly – just a cop-out. I tried a traditional round headlight as originally intended, but it looked a bit boring. It would also mean having to make a decent-looking mount for the instruments and fix up a fly screen for a bit of wind protection.

By late 2015, in the interests of getting the bike back on the road as soon as possible, I decided to stick with the Triumph fairing. This would conveniently hide and protect the original instruments which I want to retain – mileage of 71k is to be proud of! Having lopped off the panel’s side bulges to slim it down, the brackets I’d originally made to hold the lights in and mount the fairing were lost. Here it’s just taped in place:

ST1100 P4 J01 Front

New brackets to connect the panel with the Suzuki GSXR lights were made from 3mm aluminium and held in place with filler as before. The brackets had holes drilled for the filler to ooze through and secure them. Tidying and painting yet to be done:

ST1100 P4 J04 Front

The fairing looked better when closer to the forks and lower down than before – this meant the clock housing would have to be cut down to remove the projecting mounting points (and make it look less like a car dashboard).

ST1100 P4 J06 Front

More home-made 3mm aluminium brackets bolted to the fork clamps now hold the fairing on. It needed another pair of brackets at the bottom of the fairing to steady it (not yet fitted in this picture). The untidy sides of the cut-down clock housing can be seen, needing some sort of disguise – yet to be devised.

ST1100 P4 J07 Front

The removal for the clock housing mounting points meant it needed a mounting plate, which could bolt to the existing tapped holes in the top yoke. I cut this from more 3mm aluminium, with holes for the speedo drive and clock lights, then carefully bent it round a curved former – in the wrong direction. Having hammered it flat again, I could not quite replicate the nice curves I’d got the first time, but it does the job, and won’t be visible normally. I just hope the re-bending has not weakened the metal too much.

ST1100 P4 J08 Front

The original warning light unit was too large to fit between the clocks and the modified fairing, so I decided to try LEDs – 10mm diameter 12 volt units that light up in various colours. The panel is made from 2mm polystyrene sheet, glued together with MEK solvent. Two brackets bent up from scrap steel are glued to the sides with Araldite. These locate it on the front of the clock housing using the screws that retain the perspex cover. I found it best to drill the 10mm holes for the LEDs slightly under-size and finish them with a file, to ensure they lined up neatly. Strips of copper-surfaced printed circuit board (PCB) connect up the common leads (3 needed to go to negative, 4 to positive, just to make matters more interesting). The non-common leads are soldered to a strip of PCB with the copper coating cut through to separate them. The wires cut from the from the old warning lights could then be soldered to the appropriate bits of PCB without putting any strain on the LED leads.

ST1100 P4 J10 Front

The LEDs were held in place quite well by their leads, but a few blobs of Araldite added after this picture made them more secure. Once I’m happy with the unit I will probably box it in to give it a bit more protection. They appear very bright in the relative gloom of the garage, and may need some smoked perspex over them.

ST1100 P4 J12 Front

The speedometer is installed to check that the speedo drive cable run is clear. It will have to come out again to finally bolt the housing in place, with M5 bolts through the base of the housing and the bracket. There is a slight crack in the perspex cover at the bottom of the rev counter aperture. There used to be two small lugs on the back of the cover and housing with screws holding them together. I used these to attach the housing to the top yoke in the previous incarnation, causing the crack – a regrettable bodge!

Painting will have to wait for warmer, drier, weather.