A slightly wheezy Kawasaki 250TR and a Moto Morini with headaches
Green (not very) meanie about to get a transformative wake-up call
HE TR is not very fast. Pretty, yes. Nippy, no. Flat out is 75mph, and that feels very flat out indeed. Lots of mechanical thrashing noises and not very much in the way of speed. A 1971 BSA B25 is probably faster (but would have blown up long ago if subjected to the abuse the poor TR’S had).
Stage one will be a free-er breathing pipe and a bigger carb with a less restrictive filter. The aim will be to get the TR to 85mph and perhaps a bit beyond. If this proves to be not enough, then we’ll have to look at reprofiling the cam to get a bit more lift. And there are big-bore kits available in Japan, but only to 265cc, and for way too much money by the time they’re shipped here (£200). There will be pistons closer to home that would fit, but I’m fervently hoping it won’t come to that. This TR has got so few miles on it (12,000), it would be a shame to tear into a top-end that’s still factory fresh.
It’s only a two-valve engine with an unfashionably undersquare bore and stroke of 66 x 73mm and 9:1 compression (hot four-stroke singles run at 14:1). The same engine powered the Kawasaki Estrella, a soft retro cruiser thing, so its potential is limited without going mad on it with bigger valves and other exercises where the cost to effectiveness ratio becomes utterly ridiculous. If we can take a few restrictive OE bits off and bolt some hotter parts on, this is as far any reasonably sensible person would want to go [Not you then – JM].
The chassis has already benefitted from a pair of Falcon alloy-bodied shocks to replace the cheap and not at all cheerful originals. Strangely enough they came off a CZ 175 Trail I used to have and with new mounting bushes supplied by Falcon, they gave an extra half inch of rear ride height with 13-13-inch centres. It’ll get a fork service and some braided brake hose shortly too.
With the speed of today’s traffic, it feels like riding an AP50 back in 1976 – massive flat-out hilarity, but you could always do with another 50mph. This will change. Maybe not by a whole lot, but enough for it to be worthwhile. We hope.
“The aim is to get the TR to 85mph and perhaps a bit beyond with bolt-ons”
Looks like a 500, goes like a 125. Hop-up required (bike too)
32mm CV to be swapped for a 33mm Keihin CR smoothbore
Quality Falcon shocks a huge improvement