SDR200 LOVE
MCN’s performance tester Bruce Dunn reveals his fascination with this cutesy 33bhp import
You’d be forgiven for being unfamiliar with Yamaha’s SDR200. Made for just one year, this Japanesemarket-only model never officially made it to UK shores. The little single-cylinder two-stroke first came on my radar in the early 1990s after I read a road test by Rupert Paul in Performance Bikes. I was struck by its uniqueness and simplicity: that diddy trellis frame, narrow fuel tank and single seat. The SDR wasn’t trying to be anything other than a simple, lightweight, stylish roadster. And I liked that. I also liked the idea of owning a piece of Yamaha’s twostroke heritage, as well as giving me a healthy dose of nostalgia from the late 1980s when I worked as a mechanic in a bike shop.
After missing my chance to buy one from an importer in the 1990s, five years ago I stumbled across a basket case at Extreme Imports in Norfolk. It had been part of a shipment direct from Japan and was little more than a box of bits, as the engine had been deemed beyond mechanical repair. As well as 30 years of neglect, it had been fitted with a whole host of nasty accessories such as a flat bar conversion including faded pink anodised bar end weights. The bright spark who’d fitted the bars had made several unsuccessful attempts before completing the task and the top yoke looked like Swiss cheese. Aesthetics aside, the first thing I needed to do was work out how I was going to fix the engine because there was a major problem with the crankcases. During what was to be its final ride on Japanese soil, the conrod snapped and punched a hole out of the bottom of the cases. With replacements rarer than hen’s teeth, repair was my only option. Fortunately for me, the knowledge and skill of genius specials builder Allen Millyard was only a phonecall away, so I sent the cases to him to see if he thought they were salvageable. In typical Millyard style, he was confident of being able to sort it out. With the cases taken care of, there was a multitude of other jobs to get sorted. All the serviceable parts of the motor needed replacing, every bearing and seal, as well as a fresh piston and rings. You’d think that the fact the SDR was a JDM model and only produced for one year would make getting parts for it difficult, but luckily the engine shares a few components with other popular Yamaha models (early TZR125s and DT200Rs) so bearings and seals were relatively easy to sort out. With a bit of scratching around online, plus the help of my local Yamaha dealer, Webbs, I got a massive list of stuff ordered and soon found myself starting to get fussy with the aesthetics; it seemed that every time I bolted something on something else would then jump out at me. I ended up going through the whole bike, stripping everything with a view to it being replaced or restored. It took me ages poring over parts lists to see which fasteners were still available as new items, then all those that weren’t got sent off to be replated in their original zinc finish, along with the wheel spindles, nuts, bolts, washers, the lot. Having the whole engine stripped was an ideal time to get the cylinder matched to the cases, too. Similar to blueprinting, the idea is to minimise the disruption or turbulence that is caused at the point where the crankcases meet the bottom of the
‘I stumbled across a basket case in Norfolk’
cylinder. Using a Dremmel I was able to neatly match the join, one side at a time. I then reassembled the cylinder with the gasket on and marked the excess with a felt tip pen before cutting it away. Another old-school mod I couldn’t resist was to give the power valve a bit of a re-profile. A common fault with the Yamaha YPVS is that when it’s in the open position the valve never actually opens fully flush against the top of the exhaust port exit, restricting flow and limiting power a little. Not that this little bike is about power. In fact, truth be told, I’ve yet to ride it. It’s been registered on a 1986 D-plate and recently MoT’d but it’s still to have its inaugural run. I guess I don’t want to spoil the illusion; those wonderful words from Rupert in PB about how light, nippy and agile the SDR was… And back then it probably was all those things, I’m just worried that today, 34 years on, it’ll fall short – and I’ll end up with another huge shopping list of things I need to buy for it!