Thursday 14 October 2021

Suzuki GT550

The Suzuki GT550, a three cylinder two stroke that was famous for neither an excess of power nor style, looked a bit rough and sounded incredibly noisy. The bike came with an assortment of spares in several large boxes, not all the bits from a GT550. When I got the bike and bits home, I set about sorting it out.
 
Major faults were a left-hand barrel on the right, no exhaust gaskets, exhausts mounted incorrectly, head gaskets blowing, carbs leaking, carb rubbers split, chronic oil leaks, air filters and box not fitted, both tyres fitted the wrong way around, non working front brakes (though they looked great, drilled twin discs off a 750), side panels with broken mounting spigots... the list goes on and on.
 
The exhausts were removed, heads off, barrels lifted - out of the total of seven barrels I had three decent ones and therefore fitted them in the correct positions. The left hand piston was a pretty sloppy fit in its bore, but apart from that the motor was in pretty good order. The exhausts looked good but only two of the four had baffles, so I took the baffles out and made copies. I then refitted them correctly.
 
The motor ran a bit better after all that effort, but the tickover was erratic, vibration was a problem, and the carbs still leaked. I traded the bits I didn’t need for bits I could use at a breakers. With another set of carbs I got it running a lot smoother and then started about thinking about getting the bike on the road.
 
I suppose at this point I had better admit that the Suzuki is the sixth unfinished project I have bought in the past few years, but would only be the second to actually make it onto the road. The Suzuki had nine previous owners and only 26000 miles on the clock over eleven years.
 
Next, I removed the clutch cover to trace the oil leaks and try to cure them. It was lucky I did as the clutch and crank had no locking washers and both nuts were loose. I carefully reassembled them and put the motor back together using home-made gaskets.
 
The brakes caused me a lot of problems because although I was able to get them to work, the lever was very spongy and could be pulled right back to the bars - no amount of bleeding helped, neither did a new master cylinder. The cure was braided brake hose, but because this was expensive I ended up using only one disc, which proved perfectly adequate.

 
Eventually, I was ready for the MOT test. Ever the pessimist I didn’t arrange insurance as I thought it was bound to fail, taking the bike on the trailer instead. The bike sailed right through the test, but only after I had ripped off the indicators as they suddenly stopped working.
 
Straight away, I arranged insurance and tax, and took the bike out for its first run. It felt so big and heavy, with so much power, I thought my arms would be pulled out of my sockets. These feelings soon passed as I got used to it. Compared to today’s bikes it is not so fast and the handling was never very good even when they were new. I'm not a crazy rider, but it’s very easy to scrape the undercarriage on smooth bends and bumpy bends cause much consternation as it bucks and weaves. You can learn to cope with this by whacking on all the brakes before you hit the curves.
 
I was impressed enough with the bike to head off on a jaunt to Wales with the daughter on the back. After 30 miles we had to stop for a rest as the seat, which at first felt reassuringly soft, had turned into a plank. The bike was able to cruise at more than 70mph but the wind pressure meant many aches in my arms and shoulders, not helped by high bars and forward mounted footrests.
 
As we exited a bend the engine cut out onto two cylinders and then went dead.  Disaster! What had happened?  Visions of seized pistons and other horrors flitted through my mind until | tried the fuel tap. Yep, it had run out of petrol. It was only doing about 36mpg, which had caught me out. Coming back, I was enjoying myself filtering to the head of queues when the bike started to miss slightly but it went away when I turned the lights off and we reached home without incident. The next day the battery was flat but I just fitted the spare voltage control box and had no more problems.
 
Three weeks later, after doing 600 miles, I had a race with a hot hatchback which I burnt off by going to the redline in first and second. Immediately after that exploit the engine sounded like a tin of nuts being shaken and started to miss badly, eventually cutting out and refusing to start. The bike was too heavy to push home so I got the car and trailer out after walking all the way back to my house. The left-hand big-end had gone and the piston had started to break up, badly scoring the barrel. £60 bought a good used crank. A decent barrel and piston plus complete gasket set added to the expense,
 
It was almost winter by the time I rebuilt the bike but it didn’t stop me taking it for a ride up some unclassified roads that I knew only too well from rides on my trail bike. I hit a ramp at speed on the Suzi, which jerked my foot onto the gear lever sending the bike into first gear, the revs soared followed by a sickening crunch down near by my left foot. The engine stopped dead, it went from 7000rpm to zero in about a tenth of a second.
 
Oh shit! The road was still slightly damp so the bike slowly slid backwards with the front wheel locked. As there was a slight camber to the left I needed my right leg down to support the bike (it’s easier to lean up the camber), so I couldn’t use the back brake and their wasn’t any engine braking. When I tried to turn the front wheel the bike still slid in a straight line.

 
Eventually, I slid back to the hump and then manoeuvred the bike to the verge. The problem could be seen straight away. The chain had not snapped, as I'd thought, but had jumped off the rear sprocket and jammed inside the engine cover after piling up around the gearbox sprocket. So off came the clutch cover and then the crash bar that was in the way. Whilst freeing the chain I noticed that there was an oil line loose which meant removing the tank, airbox and carbs.  All this took an hour but I wasn’t in a hurry and even took some photos as I couldn’t have broken down at a more beautiful spot if I’d tried. One advantage of rebuilding cheap hacks is that you know your way around the motor and don’t panic when something goes wrong.

 
Even though one of the rollers had done a disappearing act and the chain could have snapped at any time, I carried on with my ride. After a few more miles one of the baffles came loose and I tied it back on with a plastic cable tie. Later, the clutch disappeared but I just carried on, hoping I wouldn’t have to stop - and eventually made it home in one piece. It still rattles, especially on the overrun, the only cure would be a re-bore but the cost would be too high, so I'll just run it until something goes bang and then put it in the back of my garage for a few years [looks like it went there in 1989, according to DVLA - 2021 Ed.] until a time when I can advertise it as a Japanese Classic suitable for restoration.
 
Ben Wright