Previous, Next, Back to Projects Page


  1. Starting Point
  2. Metal Polishing
  3. Engine Rebuild Notes
  4. Before Starting
  5. Sources
  6. Miscellaneous
  7. Carburetters
  8. Engine Start !

Starting Point

I am not going to list a blow by blow account of how I did my engine rebuild - the best source of information is one of the repair manuals available via eBay or an on-line bookstore on the internet. The one I like to use is the now out of print Haynes Suzuki 750, 3 Cylinder Models, Owners Workshop Manual (ISBN 85696 302 X). If you can't find one of these, the Clymer manual Suzuki 380-750cc Triples, 1972-1977 (Manual # M368) (ISBN 0-89287-285-3) is still in print - it just isn't as good as the Haynes manual - and if you do shop for the Clymer, the older ones from the 1980's include an additional chapter (chapter 9) which is missing from the more recent reprints, and which covers performance improvements, etc.. What I will do is highlight a few things to consider as you do your own rebuild.

This is what I'm starting with - it is a fairly late, 1977 model year engine (see the list of frame and engine numbers in my 'Field Guide to the Suzuki GT750" located here) that I've been saving as the crankcase halves were in good shape and it turns over smoothly. Of course, until I open it up I won't really know what problems it has, but at least it isn't seized. I do have two other engines to use as donors should it be required.

Metal Polishing

I'm still waiting for a few parts to arrive and so have started to do a bit of metal polishing of the side covers while I'm waiting. The stator cover especially was in bad shape - I picked it up on eBay and contrary to the description, it actually was damaged. The seller adjusted the price, but I was still planning to replace it with a better one as soon as I could find one - you can see it to the left. As I hadn't really done any metal polishing before, I decided this would actually be a good candidate to experiment with. The lower edge of the cover had been hit hard enough to push the metal in slightly and the surface was badly gouged. I filed this down to get the shape back, then dremelled the surface with a coarse sanding drum, then hand sanded the surface with 220 grit, followed by 400, then 1000 and 2000 wet and dry paper, then used black polishing compound with a buffing disc, followed by a bit of blue polishing compound. The end result is to the right. It actually turned out much better than I had expected, so now I think I'll keep it !

All in all, a couple of hours well spent - all I have to do now are the rest of the covers ...........

Return to Top

November Notes from the Engine Rebuild

First of all, I'm not a mechanic and as a result, these notes represent my personal opinions which may very well be incorrect – you are welcome to use any of this information, but you do so wholly at your own risk !

I've divided this into three areas:

Things to check before starting

Return to Top

Supplies and Refurbishment

Return to Top

Additions, Changes and Miscellaneous

Return to Top


Frankly - I just don't have the energy to start making this number of changes for this project, and since I have access to additional CV units via the local CVMG club to supplement the box of parts I'm starting with if required, then CV it will be. One change I will be making is to rejet the main jet on the centre carb to match the two outside ones as I will be using a three into three exhaust pipe setup, rather than the stock setup in which the centre cylinder exhaust was split into two pipes. For a main jet, I'm starting with a 115 rather than the stock 110 and we'll see how that works. The other thing I'd like to do, but will probably pass on for the moment is to install the 'anti-surge' fix that was detailed in Service Bulletin GT-36, March 11, 1977 and which can be found here in the US Service Bulletin area. As I will not be using a stock exhaust system I thought I'd wait and see whether it will actually be required.

I used the Keyster KS-0029 kits to rebuild the carbs - everything they supplied fit just fine, but I was slightly disappointed that the small o-ring (part number 13295-31210) for the needle jet was not included, nor was the fuel filter (13376-65010). Both of these are still available from Suzuki, but it would be nice of Keyster to add them to the rebuild kit just to make it fully complete. These kits are available all over the place and can be picked up on eBay for between $15 USD to $30 plus shipping. Luckily the kits do include new starter plungers which are not available from Suzuki, as these were all noticeably worn at the shoulder where the actuator engages it. The photo to the left is slightly out of focus, but gives the general idea of the amount of wear that happens on the neck at the right hand end of the old plunger, which is shown below a new one.

The other problem I had (other than the usual corrosion and cleaning items) was that the oil pump arm lever was missing the small plastic ball, or olive, used to connect the carbs to the oil injector pump rod. Each of the available carbs I had all showed the same problem as the metal bush that the ball mounted into was so badly worn that it wouldn't stay. Fortunately, our local GT750 guru Fred had a spare carburettor set I could use for parts, and so I swapped out the shaft as can be seen in the photo to the the right. My younger son Derek handled the metal polishing of the carburettor caps, and he did a nice job of making them look almost new again !

So - now I finally have a set of carburettors ready to go, and the next step will be to see if I can get the engine started !

Return to Top

December 29 update

The engine started on the first try ! Sounds pretty good considering I set the timing by eye - I will put a strobe on it tomorrow to get it set properly and as well set the carbs up with a draft gauge. While you can use mercury column vacuum gauges for this, I have always used a Uni-Syn - it is simple, easy to use, rugged, and works well on 2-strokes which have a lot of intake air pulsation which can be hard to dampen out with standard vacuum gauges.

Back to Top

Previous, Next, Back to Projects Page