After pranging my orange 1976 Buffalo, as is typical with accidents and these bikes the points cover was mangled, and as sometimes happens the points plate itself was damaged. I don’t have a problem running points – they are reliable, easy to fix, easy to trouble shoot but I had been thinking of converting over to an electronic ignition kit at some point as it is just less work to maintain. I have installed the Boyer Bransden ignition kit previously on my 1975 GT750 custom, and also on the 1974 GT550 I rebuilt, and as I had a couple of kits still sitting on the shelf I decided the time had finally come to go ahead and do the same update on the ’76.
The Boyer Bransden Micro MarkIII kit to fit the Suzuki GT750 is a bit of an odd thing as it is really designed for the Kawasaki triples, with the only difference being the (poorly written) instruction sheet and a Suzuki specific rotor. To be totally honest, it is a pain to fit and there are several alternatives available that are much easier to install. The first issue is there is no proper mounting plate included to attach the circuit board to, and so you have to either use some large washers and centre it as best you can in the contact breaker housing, or (as is suggested in the instructions) clear off your old contact breaker plate and then use it. The problem I’ve run into previously is that I’ve always then had to drill and tap new screw holes in the plate to get additional adjustment as other wise the timing can’t be easily set (too far retarded). The other problem is that the wiring and instructions as supplied tell you to hack your wiring harness to install the device which I was never too happy about. There are other options – Newtronics has reappeared on the market after having been taken over by Autocar – these are similar to the Boyer Bransden units in that you have to stash a control box somewhere, but at least they have the proper GT750 specific wiring, as well as Suzuki specific mounting adapters. They are available on eBay, but probably a better bet is Motorcycle Ignition in Australia as Shayn will at least answer questions. Another option is the ELZ3Coil from Germany which is the slickest set-up of the bunch as it is just a circuit board that replaces the contact breaker plate, and so there are no changes to the wire harness at all. Very tidy indeed ! Currently these units, with shipping to Canada included, are in the $230CDN range each, and the Boyer Bransden unit will run between $150CDN and $200CDN.
For the moment though, as I had a couple of the Boyer Bransden kits ‘on the shelf’, it seemed silly to not use one of them. This time though I decided to take a different approach and make up a proper wiring adapter to allow me to just plug into the existing harness. I had all the bits I needed to make up the fittings and also the black sleeving to cover the new harness from Vintage Connections so it was an easy task. After a couple of hours I had it all made up and installed.
The yellow arrow on the right shows where the new cable joins into the existing wiring harness – from there is runs back, following the upper right side rail and alongside the battery to the control unit marked with the second yellow arrow on the left of the photo. I’ve secured the control module on the inner rear fender and everything is neat and tidy under the seat. This location should also have the added benefit of being a cooler place than where I have previously located the units on the underside of the top frame rail, directly above the engine and under the fuel tank. We’ll see what happens I suppose – I still have one kit which I’ll keep for spares should that be required. With a new points cover in place (part number 11300-31830 and still available from Suzuki in the US for about $50USD) I was back in business !
The bike started up no problem at all and sounds OK – while there are a few signs of wear and tear from the spill evident, there isn’t anything major so I think I got off quite lightly !
I made a new stator plate by turning up a 3mm aluminium disc with large hole in the middle. At least 25mm is needed. This is simply screwed to the three lugs on the engine side cover. I added a second disc as a flange around the outside of the new plate bonded with car body mastic. It’s a bit geeky but keeps the KH250 circuit board centralised. Three M5 tapped holes and cap screws with ordinary washers locate the KH250 board.
For wiring I ran a black sleeved two core flex under the engine and up to the coils. This terminates with a two pin block connector. The other half connector is fitted to the Bransden trigger wires. The coils 6 port block connector has three yellow wires (power) and three black/white/striped wires (earths to contact breakers).
I used another block connector to make an adapter. Yellow wires about 100mm long link the male and female ends to align with coil power feeds. One is spliced to power the Bransden box. The three diodes connect to the coil end of the adapter in place of the CB wires.
This allows an easy reversion to contact breakers. In my case, three new wires would be needed to from frame side cover block connector to CBs as my original wires were hard and crispy. Others might want to swap out the OEM CB wires for safe storage.
I should add, the Bransden pickup mounting plate could easily be roughed out with angle grinder and slitting disc for file finishing. I just happen to have a small lathe. The external ring is a nice touch but not absolutely necessary.