Hacking: Stroker Stings

Seizing up a Suzuki GP100 takes a certain amount of effort. It's not simply a matter of holding the throttle open until the piston rings weld themselves into the bore. That's more likely to throw you off the road from the wicked flat-out handling or vanquished braking. The stroker single mill basically a tough little number that treated with a modicum of respect lasts for ages.

Even thrashed by mechanically illiterate youths it takes a certain amount of carnage, not to mention mileage, before the motor explodes. The easy way out is to simply never fill up the oil tank but as a connoisseur of the breed I much prefer to wring their necks until the main bearings start to judder. A weird kind of vibration that feels like the engine bolts are breaking up.

Only by the time the vibes begin to affect vision in third gear - quite an achievement on a bike that's supposed to be a mild commuter - does the engine go all plaintive, giving the rider one last chance to back off before blowing its crankshaft into a trillion pieces or seizing up, the piston sort of melting into the barrel. Either way, a hand kept on the clutch lever precludes certain death from a rear wheel skid flagellation.

It's the sheer boredom from riding a motorcycle that absolutely refuses to exceed 70mph that inspires such throttle madness. Other than falling off, there's not much more that the GP100 can offer a rider used to anything other than learner fare.

As I'd descended from the heady heights of FZR1000 ownership, thanks to a ridiculous divorce settlement (that is, I lost everything except for the cat!), something like the GP was a slap in the face that had to be dealt with by maximum violence. On the throttle rather than with the hammer, circa Kid Frost!

The silencer was already baffleless, didn't see much point in fitting a spannie - just give the local yobs an excuse to throw bricks at me. The airfilter had long since been chucked away. The carb hadn't been rejetted to suit, the mill running very hot, but this on its own was insufficient to seize it up or hole a piston.

Engine destruction was helped along by a totally unpredictable gearbox. Sometimes very slick in the Suzuki tradition, other times it would throw the engine into a false neutral and approximately one trillion revs. The little engine wanted to vibrate its way out of its mounts - they needed a weekly tightening up session, involving enough muscle to make Mad Max weak at the knees.

Whilst this was going down, the unhinged back end joined in with lunatic asylum gyrations and the front enjoyed ambitions towards turning into a pogo-stick. The sheer lightness of the machine was a mixed blessing. On the plus side, it could always be forced into line; on the negative side, it was knocked around by tarmac bumps - could end up heading for the wrong side of the road.

Often, a fast ride through stalled traffic was interrupted when the bike was thrown off line by a large bump or deep pot-hole. Considerable damage was done to the sides of cars but it seemed to make sod all difference to the state of the GP. Not that it was so much extraordinary in its toughness as being already well worn.

Seized up engines weren't a total disaster. Plenty of spares in breakers, even whole motors out of crashed commuters. I soon found that it took three piston seizures before the small-ends began to complain!

It took about one day to become completely bored with the bike but three months before I summoned up the energy to sell it at a profit. The replacement was a Honda H100, which had better brakes and handling but a motor that didn't like to rev in the same suicidal way as the GP, even when I missed a gearchange. The latter very easy on an engine with 19000 miles under its wings.

Everything about the Honda excelled in the mediocre, including a top speed of only 65mph. Well, it would do 70mph, but only if I laid myself out on the bike, found a steep hill and had a following wind. I once even managed 72mph, the grinding vibes not half as amusing as on the GP. The elements won out before I had a chance to really test the engine.

In fact, I never managed to seize the motor up. I did wear the piston rings out. The result, a huge amount of stroker smoke and not a lot of go. Secondhand rings soon bedded in.

The best thing about the H was its economy, always better than 100mpg, whereas the GP100 had often done as little as 60mpg. I was becoming such an old fogey that at one point I rode really mildly and found it was turning in 120mpg! I thought about taking up Russian Roulette but knowing my luck the pigs would've turned up and done me for firearms possession.

Instead, I took the silencer off, rode around with flames shooting out of the down-pipe and the most alarming shriek you've ever heard. No less than three cop cars were on my tail at one point, but no way they could squirt through the traffic like the H. That was one of the few advantages of riding around on a small commuter stroker, it could get in places where much bigger iron wouldn't dream of going.

Even that didn't destroy the Honda, so I sold it on at another mild profit and bought an old GP125 that the owner claimed made a genuine 20 horses. The wail out of the expansion chamber was straight off a racetrack and the engine just coughed and spluttered at the lower end of the rev range.

When the power finally coalesced it didn't seem that much heavier than on the GP100 but it continued to pour in until an easy 80mph was on the clock. Fortunately, the forks and front disc were off something newer whilst a pair of Girling shocks took care of the rear end. The latter old but almost too firm. That only left the swinging arm bearings to waggle around once the speed was above 70mph. Much better than a stock, worn GP100.

It was still more of an irritating bike to ride than an exciting one. Had to be revved to infinity everywhere, otherwise it didn't want to run. The resulting awful racket, in which by some strange process the engine pinging seemed to be amplified by the banshee exhaust wail, had everyone out for my neck. I didn't mind being an antisocial bugger - it kind of came naturally - but the GP didn't really reward such a rolling crime wave.

Which has to be expected. I destroyed the GP125's crankshaft which meant the engine was a write-off. Ended up back where I started, a GP100 engine installed!

R. K.