It all started three years ago when the local hoodlum - there always seems to be one in every borough - decided it was time to sell his ‘76 race spec GT750. For some obscure reason he reckoned I would be the ideal purchaser after I'd commented favourably on the banshee wail out of the three spannies. I demurred, not being in favour of clip-ons halfway down the forks nor even of 2000rpm power bands.
‘Don't worry about that, mate,’ said he. ‘I’ve got all the stock parts in the shed.’ He spoke as he rode, so fast that all the words merged together and a moment's inattention rendered them a stream of babble. His hands shook like he was in the throes of an epileptic fit and his pupils were tiny pin-pricks. ‘Keep ‘er for the weekend, see what you think.’
I dutifully explored the parameters of a race replica with a heavily tuned three cylinder stroker mill and truth to tell was more scared than impressed. Something to do with the effect of shot swinging arm bearings on my 125mph velocity - just as well that the motorway was both wide and deserted.
‘Don't worry about that, mate, you'll soon get used to it. All those seventies Japs were the same,’ he babbled. ‘Look, I want the bike to go to a good home so I'll let you have it for £500 with all the spares thrown in. I’ve got a shed full of stuff back home.’ It was the five hundred quid that got my attention, good GT750s going for around a grand. All it'd take was a bit of spanner wielding to get her back to stock and I'd double my money.
The deal was done, a Transit load of bits delivered and the GT employed for the drag into work. I say drag, as the only way the Suzuki would successfully run was if I was trying to break the standing quarter record. There was no knowing what mileage the 15 year old engine had done, but it was large enough to have worn out the gearbox selectors. Judging by the way the engine flew into the red when a false neutral was hit it was just as well that there were no valves to tangle but I guess piston speeds must've approached warp two.
There were some other malicious traits as well. The twin discs out front may or may not have been stock - I suspect that they were but they were evil and extreme in the wet. I was never sure if they were going to instantly lock up the front wheel or refuse to work altogether. They always juddered because the discs were a little warped but they seemed too thin to risk having machined. This fragile front end was complemented by a rear drum that simply didn't work. Removal of the back wheel revealed this was because there were no shoes in it!
On most bikes there’s a useful bit of engine braking, on the GT it was like slamming into a brick wall. So efficacious that the chain threatened to leap off the sprockets and if maintained for more than a couple of seconds all three spark plugs would oil up to a degree that required a plug swap. Slowing down, then, meant lots of throttle blipping and argy-bargy on the gear change.
Together with vague and sometimes frightening handling, these traits turned me into a nervous wreck after a couple of weeks of impossible spinal contortions. When I started going through the cache of spares I found that anything that wasn’t worn out was rusted through. I had a great big heap of scrap cluttering up my garage and a malevolent cycle sitting in the front garden.
It was shortly after this realisation that a strange and terrifying thing began to happen for no reason I could put a finger on, other than the terrific wail out of the exhaust system and the relief of fitting a proper pair of handlebars (as the clamps hadn’t been removed). Yes, I fell headlong in love with the GT750, the kind of outrageous passion a middle-aged man feels for a teenage girl glowing with the first flush of sexuality.
I was determined, though, to put the bike back into a more useful stock form. This quest was intensified when after two months the pistons started to rattle and the engine almost refused to run at any revs. Being perverted, I wanted to keep the spannies, so the hunt for used barrels and pistons was on - my engine had such very large holes taken out of the ports it was a wonder it’d run for so long. GT750s are getting a bit long in the tooth, these days, but after two weeks of frantic phone calls I had the bits in my hands. I'd also found a lot of cycle parts, spending about three hundred quid in all. A bit excessive but at least the GT would more or less be back to stock.
After a lot of hassle with the carb jets I was once again on the road. The stock engine was a lot more responsive and easy running but lacked the hard edged feel of the earlier effort. I was soon suffering withdrawal symptoms! Consolation came in the form of improved economy (35 compared to 25mpg), being able to get to work without a plug swap and an end to the almost compulsory police chases that were resultant from mono-wheeling down the High Street.
New swinging arm bearings, a pair of Koni shocks and a set of Metzeler tyres were a sufficient shock to the system to transform the wobbles and vagueness into a semblance of civility and predictability, That only left the brakes, the rear end easily sorted with a new pair of shoes and the front rather more expensively cured with a whole GS750 front end, which went on with surprising ease and really did make the bike much nicer.
Having finally got the GT750 into a state where it could be safely introduced to my friends, I was a bit horrified to find clouds of steam billowing out of the radiator. This turned out not to be due to any fault in the cooling system but because the ignition timing had slipped, resulting in an engine that wanted to go molten. The pistons were added to my collection of paperweights and old race engine items bodged in with a new set of rings.
One thing I had noted with the rebuilt motor was an increase in vibes between 4000 and 6000rpm. With the race pistons, which were cut back and made from better alloy, and therefore a lot lighter than stock, the vibes were noticeably diminished. It may just be that the crankshaft was originally balanced to suit these pistons, but I think having markedly less reciprocating mass must make a difference.
There are all kinds of stories about stroker crankshafts wearing out in a big way but one of the few verifiable facts about the GT was that 4000 miles before I bought it the crankshaft had been rebuilt. GT750 cranks are usually good for at least 20000 miles, as long as an eye is kept on the oil level which can do a disappearing act in a remarkably short time when the motor is caned relentlessly. I've got it down to a pint in 50 miles, although twice that is more normal. Yes, the infamous stroker haze of pollutants is present for most of the time.
I wasn’t sure how long my engine bodge was going to last but I needn't have worried because the gearbox went first. As mentioned, it'd always been a bit nasty but this time some teeth spat off the cogs, causing an intense grinding sensation to rumble through the chassis. I was only thankful that the damage was contained within the gearbox itself. It took six months to find used gearbox bits that weren't equally knackered. I took the opportunity to do a full cycle part renovation, which cost about £250.
Back on the road I had a gay old time with all systems go - for three months! Then the engine seized up solid at 80mph, only a desperate snatch at the clutch lever saved me from rolling off the road. The pistons were so solidly welded to the barrels that it took me a week's worth of hammering to free the components. I had a perfect chassis with a ruined engine; rather like a beautiful woman with AIDS!
Still, I didn’t give up and went on a hunt for engine parts that took almost eight months as the seized oil pump had led to comprehensive damage. I still have the GT750 and, at the moment, it runs very nicely. I have something more modern for general use but it does nothing for my heart or soul. The Suzuki, inexplicably, remains at the centre of my life.
Geoff Davis