Suzuki RG500 Restoration

Suzuki RG500 Restoration




1986 Suzuki RG500 GammaKeith Dickinson is a 45 year-old Scientist, and part-time petrol head, who has always serviced and repairing his own bikes and cars. “I’ve had a bike of some sort on the road ever since I was 16 years old and have restored and rebuilt several bikes over the years – as well a Triumph Spitfire which succeeded in putting me off car restoration for life. I currently also have a Ducati 888 Strada as well as a 1949 Triumph T100 donated by my father that I managed to get back on the road this year. Our three kids limit my tinkering time a bit, but I still manage a few hours a week.”

Suzuki RG500 Gamma“In my 20’s I put a huge mileage on a Honda CB750K6 and it was amazingly reliable but boring so I switched to a Suzuki GT750A, which I rebuilt from the ground up. It was very similar in many ways to the CB750 but the power delivery was so much smoother and more fun and it had that addictive 2-stroke wail. Thus, I watched with great interest when the race replica 2-strokes came out during the 1980s, I was very tempted but put off by how impractical I thought they would be to own. About ten years ago my brother mentioned there was one for sale near him at a local dealership and with my wife’s encouragement (honestly!) we went to see it. Any kind of rationality went out of the window when I saw (and heard) it and I bought it straight away.

I rode it around for that first summer, but it soon became clear all was not well, in particular, the handling was obviously much different to what I was used to, but still it just didn’t feel right, and the fork legs were pitted and leaking. The engine also seemed to be a bit noisy, didn’t look like it had been stripped before and at 16,000 miles was due at least new rings. So I ended up completely stripping the bike and engine.

Suzuki RG500The front end needed the forks sliders re-chroming, new headraces, and new bushes in the forks. The brakes were rebuilt with new seals, which is no small job as there are a total of 10 pistons, and 20 seals. The rear end was suffering from some badly worn mono-shock bushes and some missing spacers/seals. In particular the rear torque arm had been assembled incorrectly and was locked solid. The engine was completely stripped and had the expected worn rings. There were, however, bad scores above the exhaust ports on both front cylinders and this seemed to have been caused by the disk-valve seats breaking up, the barrels went to Stan Stephens for rebores on all cylinders.

Two new disk valves, seats and covers were also needed, while the crankshaft and rest of the engine was fine, but the outer main bearings and some of the gearbox bearings were a bit noisy, so all were replaced as a precaution.

1986 Suzuki RG500The engine on the RG500 is complicated for a 2-stroke, but rebuilding them is fairly straightforward, as long as you have the excellent Suzuki workshop manual and treat them gently. I was surprised that the gearbox looked fine as they are the main weak point in the engine and it’s not uncommon for gears to break up and exit expensively through the cases.

The bodywork was pretty much OK so left alone though replacement front and rear mudguards were eventually sourced via eBay. The bike ended up pretty original but I fitted in-line Yamaha oil check valves to the injection lines as the original design ends up leaking two stroke oil into the carbs and then onto the floor. Since the rebuild, the RG has been a reliable and fun transport and I’ve done close to 6,000 miles (a fair few of those at track-days). The only breakdown I have had was a seize at 130mph when the back right piston detonated. I managed to get away without needing a re-bore as, once the melted aluminium on the bore had been dissolved with acid, most of the marks vanished after a DIY hone. I never did find a cause for it but suspect a bad batch of petrol may have been the culprit and I went up one size on the main jet for safety. As a precaution, I also treated the gearbox to new 1st, 2nd and 6th gears; this is a relatively straightforward job, due to the cassette gearbox, and you can get the whole gear assembly out in approximately 30 minutes.

1986 RG500I’ve deliberately put off a re-spray until now, as I knew I probably would not want to risk it on the track after that. Thus, this winter it will be stripped down again with the intention of getting it close to concours condition. I would end in saying that anyone who has been put off buying an RG500 because of its fearsome reputation should really re-think. These bikes are really something special and their like will probably never be seen again, maintaining one isn’t a nightmare and there is lots of support from like minded owners.”

Useful RG500 Contacts
The RG500 mailing list – http://edj.net/2stroke/rg/

Spares Direct tel 0208 969 0741 – www.sparesdirect.co.uk/

Stan Stephens tel 01732 760 337 – www.stanstephens.com

RG500.com – www.rg500.com

HCP Ltd tel 01623 862 314 – www.hardchromeplating.co.uk

RG500 Top Tips

  • Always take a knowledgeable friend with you when buying a bike to provide an unbiased view and to help you walk away if its not quite right.
  • Don’t slag off the handling, brakes etc of any bike until you have made sure the stock items are working properly first.
  • Never trust the previous owners mechanical skills and check everything sooner rather than later. Old bikes have had plenty of time to accumulate botches and I’ve never stripped a vehicle without finding at least one thing that shocked me.
  • If buying a bike to restore then always budget as much as possible for the initial purchase. Restoration always costs more than you think and getting a ‘good’ bike in the first place is almost always much cheaper in the end.
  • If you need a tool to do a job then don’t hesitate to either buy it or make it rather than muddling through.
  • Never believe anyone who says a particular job is too difficult to take on. The hard jobs are always the ones that end up giving you the most satisfaction. If you are willing to take your time and research the job properly first then it’s amazing what can be done at home. In particular, remember that people have been saying for generations that ‘modern’ vehicles are too complicated to work on at home.

1986 Suzuki RG500 Gamma Specifications

  • Price: £2000
  • Value now (est): £ 3500-5000
  • Power: 95bhp
  • Torque: 52ft-lb
  • Top speed: 143mph
  • Dry weight: 154kg
  • Colours: Blue/White
  • Fuel: 22litres
  • Rake/trail: 25.2deg/110mm
  • Seat height: 770mm
  • Wheelbase: 1425mm
  • Engine: liquid-cooled 498cc (56 x 50 mm), 4-cylinder, disc valve, two-stroke. 4 x 28mm Mikuni carbs. 6-gears. Chain final drive
  • Chassis: square section alloy frame, 38mm adjustable telescopic forks, Full floating monoshock with adjustable preload
  • Brakes: 260mm front discs with 4-piston calipers, 210mm disc, 2-piston caliper, Tyres: 110/90 x 16 front, 120/90 x 17 rear

Suzuki RG500 Gamma Gallery

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