Starting the SP took some effort. The big four stroke single had been upgraded with wild cams and electronic ignition, a combination that didn't work very well below 2000rpm. I often had to do a running start, the shock of my 75 kilos lurching on to the saddle the only way to blast her into life of a cold morning.
Once fired up, the motor had a touch of the tearaway, wanted to shoot up to about 8500rpm before things slackened off. The blare out of the exhaust was something out of the distant past, a vintage race track star in the making. Car drivers never acted as if I didn't exist and quite a few plod had some unwarranted exercise running alongside waving their notebooks. As if I, or any other sane person, would take any notice.
This was a very light and narrow motorcycle which despite its tallness (no problem for me at six foot) was easy to throw around. In heavy traffic, a useful view over the cages' roofs was afforded which went some way to compensating for the very poor SLS drum brakes as I could usually second-guess what the drivers were up to. Most of the time.
On a good day, I could extract one emergency stop out of the brakes, then they went all soggy, as in bloody useless. The drums are too small, there's almost no point in messing around with various shoe and lining combinations, the best bet's to find something modern, but I haven't bothered and they haven't got me yet. Lots of near misses.
So far, then, the SP has awkward starting and dangerous braking, with enough go to get the adrenaline running. What else? Brilliant economy, for a start - it's a very bad time when it does worse than 70mpg, 80mpg's usually possible and as much as 90mpg achievable. Compared to any other modern bike able to break through 80mph it's brilliant.
The design has a couple of weak spots - the kickstart gear and valve train - but other than that it's a pretty tough mill. Good for 35-40,000 miles before the bore or piston's gone. The key is very regular oil changes, using top grade stuff - I use Duckham's every 750 miles. It doesn't take much oil, so not as expensive as it sounds. Crankshaft bearings are next in line, around 50,000 miles - by then it's time to look around for a replacement engine, either another SP (or DR400) or something more modern. I've got one SP370 and one DR400 mill, both in need of attention but salvageable.
The condition of the cycle parts is usually down to how much off-road riding the bikes have done. They are quite accomplished trailsters with stock engines, though mine is quite fierce, likely to send me off the side of a mountain if used in anger. The fact that the engine cuts out if used at tickover revs means it's not a very good off-road tool in its current form.
Road use, the cycle parts don't go off particularly rapidly, fading away finish-wise rather than being blistered with rust, with the exception of the swinging arm and its bearings, both extremely quick rot. The electrics are more of a worry, with a typical dodgy Suzuki generator. The tiny battery doesn't help matters any. The lights and horn are predictably pathetic and not easily upgraded. It's possible to wire up the ignition so that it can run without a battery but don't expect anything else to work.
The brakes and lights are definite limits on its practicality but don't get in the way of having fun on the road, it's a thrill a second kind of ride if you are into big singles, minimal mass and instant torque. I give any number of modernly mounted riders a lot of heartache, not to mention earache. I wear earplugs myself, so haven't gone insane yet - probably!
SP370/400's and DR400's do inspire a large amount of loyalty amongst owners, and despite being twenty-odd years old, there are still many reasonable ones on offer. At less than a grand a throw, well worth a blast.
Andy Paine