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'71 Suzuki GT500

Discussion in 'Bike Reviews, Questions and Suggestions' at netrider.net.au started by MeltingDOg, Mar 26, 2012.

  1. Hi all,

    I was riding past the bike shop in my local area when I spotted something out of the ordinary for sale out front. I dropped in and had a closer look. It turned out to be a Suzuki GT500 modified to be a Cafe Racer. It was a very tidy bike with new paint and a reconditioned engine with only 1000ks on the the clock. It was obvious the previous owner who had traded it in for a tourer took a lot of pride in it.

    Asking more about it I was surprised to learn it was actually a 500cc 2 parallel cylinder two stroke. Eventually I was coerced into taking it for a test ride and man what a great bike it is! As I have just finished being one my restricted licence I am considering upgrading to something a bit bigger.

    So I wanted to ask if anyone has had experience with one of these?

    I asked the sales guy and he said maintenance is easy as its a very simple engine - but that could just be sales guy talk.

    Are these bikes easy to maintain? I have to admit the idea of a two stroke chewing oil scares me a bit, but then again I'm just not used to them.

    They are asking $7000, which I think is very steep (but it does have recondition engine, new electrics and paint/chrome). Would anyone know what I should be paying for a bike like this?

    Thanks! Any advice is appreciated!
  2. Probably the best of Suzuki's air cooled two-strokes. The sales guy is right in that they are mechanically simple and easy to work on and the 500 has something of an enthusiast following so spares and knowledge seem to be available as long as you understand that you probably won't be getting much of either from your local Suzuki dealer.

    The 500 is popular with classic racers too, which is a bonus when it comes to knowledge but may not be with regard to purchase prices. $7k seems a bit steep to someone who can remember these changing hands for a couple of hundred quid for a nice one, but there aren't that many left so prices are what they are if you really want one.

    The only real mechanical issue to watch (apart from all the stuff that could be a problem with a 40 year old bike :D) is the crankshaft seals. These dry out if the bike is left standing for long periods and the vital lip of the seal sticks to the surface of the crank. When the engine is next turned over, the lip of the seal is damaged. When the seal fails, the engine will suck in and burn the gearbox oil, so a failed seal (not that big a deal in itself on a stroker) can lead to a lunched gearbox if the rider doesn't catch the dropping oil level in time.

    In short, they're not bad for their day but that day was four decades ago. Chuck on decent tyres and shocks and it will handle fine, but you'll never get the brakes to modern standards with any semblance of originality. And I'd be doubtful of the practicality of using a 70s bike on an everyday basis. It can be done but requires a fair maintenance workload and a stockpile of common spares to make up for a lack of instant local availability.

    If you go into it with your eyes open as to those shortcomings, there are far worse bikes from the era to have a bit of fun with.
  3. Hey all,

    So I ended up getting the T500!!!

    I didnt like the price of $7,000 so I suggested $5,000 thinking they would reject it. We actually settled at $5,200!

    Picked it up today and went for spin! Bloody brilliant!...until all of a sudden it stopped dead. Couldnt start it at all, not even roll starting. Spent about 1.5hrs by the side of the road twiddling bits here and there to no avail until finally I messed about with what I thought was at the time a hand throttle near the carbi's. Turns out it was some kind of pressure relief valve (?) that was open so there was no pressure in the cyclinders. Closed them and its fine!

    Now, I am going to sound like a total newb but does anyone know what these are for? Or even if they are pressure release valves? I have found this image here:


    The thing I am referring to is the rusty part at the top right of the carbi connecting to that brass knob.

    If anyone could help me out that would be awesome!

    • Like Like x 1
  4. That's the choke mechanism.
    Actually not a 'choke' as these richen mixture by blanking off air supply (see early CB750 Honda) but a separate fuel port to add extra fuel to the cylinder to make the mixture extra rich for starting.
    The lever connected to the plunger through the rod does the same on the other carb. The lever most probably has 'CHOKE' stamped on it.
    You will only need to run on choke for a minute or so. Any more and you risk the dreaded fouled spark plug. Always keep a couple of new plugs with you (and a plug spanner!) to get you going when the inevitable happens.
    In case you're wondering, richer does not mean more power on these 2 strokes.
    Welcome to the world of classic strokers and get a workshop manual.
  5. #5 jag131990, Apr 2, 2012
    Last edited by a moderator: Oct 24, 2015
    $5200 on a bike from 1971? Man they saw you coming.
  6. Yes carrying spare plugs is a must with a 2-smoker. It is an awesome bike though, I looked long and hard at a GT550 not long ago. Enjoy, and you will be much more mechanically minded soon.
  7. #7 kols_kebabs, Apr 2, 2012
    Last edited by a moderator: Oct 24, 2015

    • Like Like x 1
  8. #8 MeltingDOg, Apr 2, 2012
    Last edited by a moderator: Oct 24, 2015
    Actually, they saw 5 people coming - 5 others tried to buy it after I put down the deposit.

    It is a professionally modified cafe racer with brand new parts
  9. Yeah my feeling is they may have also put in the wrong spark plugs. I had another similar issue and this time I took the plugs out, cleaned them and it started first time. I'm guessing this may be either becuase the plugs are getting dirty to quickly or that they are not liking the heat (and taking them out cools them enough to use again). Does anyone know a suitable plug type to use?
  10. This.

    and this.

    I doubt they're the wrong plugs. What colour were they before you cleaned them? And how have you got this far without posting any pics of your bike?
    • Like Like x 1
  11. This too. WIth any 40 yo bike you will be doing a fair bit of fiddling on a regular basis. With a 40 yo stroker you will be doing it even more regularly. Probably nothing major but a constant round of tweaks and adjustments.
  12. Thanks all.

    Yes a found a manuel PDF online which is really handy.

    Also i now suspect it the quantity of oil being fed into the engine thats causing it. Now, it is a 2 stroke but it does produce A LOT of smoke so this could be it.

    I am going to re-adjust the valve that feeds in the oil. The manuel gives instructions how.

    Ill let you know how I go.

    Pics coming soon!
  13. On modern oils, even an old stroker shouldn't lay a battleship style smoke screen. If the oil pump is adjusted correctly and a good quality oil is used there should be no more than a barely visible haze under most circumstances.

    It's worth bearing in mind that excessive oil has more effects than fouling your plugs. It also lowers the efffective octane rating of your fuel and, in extreme cases, can affect the compression ratio. On premix lubed engines, more oil in the fuel also leans the mixture although I think (haven't actually worked it out properly) this shouldn't be an issue with an oil injection system.

    As to what oil, it's not an RS/RGV/TZR so I wouldn't go to a synthetic. Any brand named mineral oil not sold specifically for lawnmowers should be fine.
  14. Hi all,

    Pics of the bike are here

    I can also confirm the spark plugs in there are the correct ones. So that leaves the oil. I took of the cover to have a look at the oil pump mechanism which is attached to the throttle.

    I don't want to turn this post entirely into a maintenance post but I think it would be good to help out others.

    Heres the mechanism:


    Now, in my manuel it says certain marks on the lever and pump are meant to line up. Trouble is the picture on the manuel is absolutely terrible! I look around for ages to find these marks and now think I have it set up properly.

    Here are the marks:


    If anyone can confirm these are correct I will be much indebted to you! But for now I will just take it for a quick run and see how she goes! Ta again!
  15. I have a 1977 GT500B. Purchased as a wreck & did a total rebuild, gearbox, crank, carbis etc, etc. They are very easy to maintain & enjoyable to ride.