Dave’s Yamaha TDR350 special

OK, it’s a TDR350 in the loosest terms. But with a Honda WR450 chassis and 17 inch wheels it does combine the searing power of a 350 Yam with the agility of a supermoto.

Dave’s last bike in the Rupe’s Rewires shop was an RD500 special. He did this one using his considerable engineering skills: he’s moved the swing arm pivot, refashioned the exhausts (both from a smaller crosser), made up lower frame rails, added an Aprilia swing arm, and fitted all the electricals.

As there is only a front and rear light, brake light and horn, the loom wasn’t too tricky. The harder bit was figuring out how to run the loom to escape the heat from the exhausts. Pretty soon I realised it all needed to be in the only cool place: under the seat on the left side. The LED lights helped. Their minimal current draw allows you to use skinny cable and tiny SM connectors.

Dave had a bit of rough luck with this build. The regulator rectifier tested fine on the bench, but blew a diode within a few minutes of running. Fortunately I found the issue before it ate the battery and stator, which can happen if you run a bike for ages on a dead reg rec. To add insult to injury, the (used) horn was duff too.

It’s going to be an amazing pub bike. The inevitable puzzled looks from people clocking the twin expansion chambers will be a bonus.