Archive for April, 2009

Wow be unto the 125 class buyer. It is now officially Decision Time. We’ll take it for granted that you want to win, and you want to spend as little as you have in order to wn (or do reasonably well) in that class.

Up until now, you’ve been faced with several alternatives, let’s examine a few of them in retrospect Read the rest of this entry »

Original dealer brochure for the Suzuki TM400

Original brochure showing what they looked like new!

This one could be a bit of a challenge, to restore and to ride. For now it is placed against the wall of the garage waiting its turn.

Came across this 1972 test in a DIRT BIKE magazine to tame the 71 – 72 TM400 Cyclone motors, I have heard of other solutions using the TS400 ignition systems but I have not found any written tests on that yet. Not sure if the 74 model needed the same treatment as the 75 TM400 was said to be ok but by then the RM series were out and that was the end of the TM’s.

A BOLT-ON SOLUTION for TM400 sweaty palms?

Some people have this healthy fear of snakes. Others cringe inwardly when they find themselves alone in a dark room. Yet others can’t stand being up high, or even worse-flying in an airplane. All of these fears pale by comparison to the fear-inducing potential of a stock 400 Suzuki MXer. This is one of the truly Frightening Machines Of All Time.

What makes it increase your pueker power? Part of the problem lies with the frame. another part with the suspension—but the bulk of the guilt lies with the power band of the engine.

There is no such thing as “just a little more” from the twist grip on the TM 400. Nosirree. You either get a giant handful or the engine stalls. This phenomenon is, of course. caused by the lack of flywheel weight. A logical cure, then, would be to bolt on some weight to slow the rev buildup down to a more usable level. Remember, power that does not get to the ground is wasted power. And slower building revs mean that the bike will be easier to ride. At least in theory.

Read the rest of this entry »

Everybody jabbers on and on about changing the powerband of a motorcycle engine. The scrambles boys want a bundle on top; the MX-ers want a nice, even spread.

Sooo, motors got ported, polished, reeded, drilled, stuffed, files, tampered, folded, spindled and mutilated in the never ending quest for the prefect powerband.

However, only one path has been found to that elusive Perfect Power-band: cubic inches. Or even better, cubic feet.

Yup. You can achieve bottom end, top end and even middle end, if the motor has a big cnough hole in it (and a piston to fit that hole).

Naturally, whenever we get a big-incher in for a test, we expect to be greeted by power. Buckets of power all over the place, Power from idle to peak revs. We expect to put the bike in top gear and go boom-boom-boom down thc road, digging trenches as thc engine barely turns ovcr.

A short while ago, Yamaha dropped off one of their new 500cc bikes at our offices. And promptly blew our preconveived notions about big-inch power right out of the lunch box. Read the rest of this entry »