Jeff Ware strips the square four motor. What does he find?
G’day! There have been a few issues since my last update. Hopefully you enjoyed my story about the Aprilia RS250 restoration and sadly, inevitable sale, such is life… The RG500 is becoming a bit more of a task than I had hoped for but I’m trying not to get too fussy. I want it ready to ride for spring over here so I only have a few months. It’s too cold now, being winter and only 15C most days (well it’s cold for us Aussies). I’ve also just restored a 1985 GSX-R750F from scratch, which just needs to be dressed now, so that has kept me busy. The RG500 carburettors were really grubby. Of all things not drained or prepared for 17 years’ storage, it had to be the carburettors. The fuel tank was empty but the carbs not drained. I’m not sure why. Anyway, the result was severe clogging up and crystallisation as fuel evaporated or turned to syrup over the many years the RG stood still on its stands. One carburettor had a broken float pin post – it had clean snapped off, so repairing that was tricky. I drilled out the pin and the carb body and tapped a stainless pin into it and joined them together again with some liquid steel. It worked a treat. I also fitted a new float to that carb as the original one was damaged. With the carbs fully stripped I popped them in the ultrasonic cleaner and got them all mint again, back to as new. You can’t beat ultrasonic cleaners in my opinion. The one I used belongs to a mate, so I just headed over to his shed, beers in hand, popped them in, had a beer, returned the following arvo for a few more amber refreshments and gave the trick little flat slides a rinse and blow out, then stumbled my way home. We have no footpaths here, so I was pretty annoyed when I tripped and dropped my immaculate, clean carburettors in the dirt. Bugger! I assembled the fantastic four with brand new jets and sat them aside ready to pop back on once the new rotary discs and O-rings arrive, which should be by the time you read this. Once they are fitted I can refit the carbs and balance the slides.
The next job to tackle was to inspect the clutch and gearbox, just make sure everything inside the bike was in good order and that no nasty surprises were going to be had once I hit the open road on my dream bike. I’m happy to report that all was fine inside the bike and nothing at all needed replacing, not even a clutch plate or spring. I’m amazed at the condition of the gearbox and clutch considering the mileage of the bike. It says a lot for regular oil changes and treating a bike with a lot of TLC throughout its life. I noticed in Helmut’s maintenance notes that he regularly added Nulon gearbox additive to the gearbox each oil change. A bit like the Slick 50 myth, perhaps these things actually do work! I reckon very few of us ever own anything long enough to inspect and assess wear to find the truth… Well, this may be the answer! I was hoping to get the pipes off, decoked and painted but have not had a chance and I need to paint the wheels, replace the fork seals and rebuild the brakes first as the bike is being supported by the pipes right now. Once I do get the pipes off, I can do my final engine inspections, including power valves, and then assemble it all and fire the bike up. I can’t wait… Chassis-wise I’ve got stainless steel
brake lines by Venhill to fit to the bike, as I really do want good brakes. I haven’t decided on rubber yet but will most likely go for Pirellis and I want to replace the shock but need to do more research, so any of you with any suggestions on RG500 shock replacement, let us know – any advice appreciated. I also bought a single seat cover as I really want that look as I think it really sets the bike off. Next issue the bike will be running, with freshly painted pipes and radiator and a new lease of life. Hopefully I will also have the wheels painted and wearing new hoops and might even have the brakes done.
11/ The carburettors being stripped to go into the ultrasonic cleaner. They are a really neat little carburettor and easy to strip.
52/ The repaired float pivot post that was broken off. I drilled it out and fitted a stainless steel pin inside, which worked fine and saved me a small fortune. 3/ This is the jet kit I bought from Japan. I have heard and read both good and bad reports about these so will have to see for myself once I get the bike on the dyno for tuning. The kit comes with everything needed and at the right price so I am more than happy to give it a go. I also have the original jets, although they are most likely worn. 4/ Got this float out of Singapore of all places. It wasn’t easy to find a single OEM RG500 float! 5/ The carbies were fully stripped and placed in an ultrasonic cleaner for 24 hours. 6/ All like new, they came out really clean ready for new jets, new needle and seats, gaskets and O-rings.
10 10/Float heights set and mixtures. Slides will be balanced later. 11/ The exhaust pipes need a clean-out and repaint so that will happen as soon as I can get the bike supported at each end, which will be after I do the forks and source a shock, plus check the swingarm pivots. 12/ Bit of RG500 inspiration never goes astray in the shed!
8 7/ The carburettors came up mint, all ready to be refitted and balanced once the manifolds are back on, which depends on the arrival of the rotary discs and O-rings for the covers. 8/ This is what each carb looked like after standing with fuel in them for 17 years!. 9/ The clutch and gearbox are all okay in my bike, thankfully. Stripping and inspecting was easy thanks to the cassette-style gearbox, very ahead of its time in 1985 for a proddie bike. I gave it all a good clean-out and reassembled it, torquing everything up to exact factory specifications.