This is a really advanced custom build

Space is incredibly tight, especially as all the connectors have to be mud proof and therefore a bit bigger than usual

Dave will have to remove the loom to paint the frame, so the tail light wires use Deutsch pins and heat shrink, which can get back through the sub frame tubes

Three-position ignition switch, waterproofed as much as poss. The bracket is just for location – Dave is a far better fabricator than I am

The carbon electrics tray carries the various interlock systems which the original ignition uses. The Ignitech didn’t need any of them!

Dave’s Yamaha WR450 Malle Mile bike

This amazing Yamaha special turned out to be one of the biggest headaches I’ve ever worked on. That’s no reflection of builder and owner Dave, whose work is amazing. I just couldn’t get the damn thing to spark! I am grateful for his patience while we tried several possible solutions.

In the end it turned out to be simple bad luck. The original Yamaha CDI unit, which had worked fine before the loom build, was dead. According to CDI specialists Rex’s Speedshop, old units can go pop when confronted with healthy voltage for the first time in a long time. An Ignitech replacement was the answer – as it so often is.

The bike itself is extraordinary. The WR450 motor sits in a modified Yamaha XS500 frame with a custom oil tank, Öhlins forks and shocks, hand-made mudguards and number boards, a vintage Yamaha tank (probably a DT series) and a one-off high-level exhaust. Electricals: LED warning lights and tail light, M-Blaze indicators, aftermarket headlight. The lithium battery sits in a heat resistant 3D printed box.

The stock WR charging system isn’t suitable for a lithium battery so we got Rex’s Speedshop to rewind the stator. Alongside a MOSFET regulator rectifier we hope it will be enough to make the battery behave. There just isn’t room for a traditional battery with enough guts to turn the starter over.

With all the delays, Dave couldn’t get the bike ready for this year’s Malle Mile, but it should be there in 2022. I can’t wait to see it.

We finally ended up with an Ignitech CDI ignition after the original Yamaha one failed. This pic is during testing

Tail light wires go through the rear sub frame

Subtle warning lights

One of the most original and well-built bikes I’ve worked on