Piece Build a GT380

General discussion about Street two-stroke Suzuki motorcycles.

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lewis1956
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Suzuki 2-Strokes: 1970 T350 Now; TS250, GT380, TM400 Past
Location: Yorba Linda, CA

Piece Build a GT380

Post by lewis1956 »

Have been looking for a 1972 GT380 for quite a while with no luck. Am thinking of piecing one together as I have lots of time on my hands now. Was wondering if you GT gurus could give me some general guidance regarding how to begin. I would like to put a 1972 together, but have found a 1975 engine to rebuild so I guess that might cause me to resurrect a 75. I do know that they changed frames, carbs, brakes and other stuff during the production years, but was wondering what would be a good strategy to pursue. Engine or frame first? Years with greatest compatibility with other years to help in sourcing parts? Anyway, whatever you can share would be appreciated. Thanks.
Craig380
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Re: Piece Build a GT380

Post by Craig380 »

The J & K models (roughly corresponding to '72 and '73) had slightly different exhaust pipes and frames (the mounting points were in a different position, but people have made simple adapter plates) and of course the J model had the drum brake in the front wheel.

You can't mix J/K cylinders with the later plate-mounted carbs (the inlet stubs cast on the early cylinders are too short), but any year engine will fit any year frame. And by the time you get to the L model, Suzuki hardly changed anything on the bike apart from paint.

Suzi was also notorious for using up old stocks of accessories like front mudguards, turn indicators etc so while some people argue about which model year a specific type of indicator or fender etc, belongs to, the factory was not at all consistent in what it fitted to its bikes.

In general, it would be easier to put together a L/M/A model bike, because of greater parts commonality and the fact that Suzi sold more of the later bikes, so there are more parts around.

Good luck with your project!
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
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jabcb
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Suzuki 2-Strokes: 69 T350 thru 75 GT750
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Re: Piece Build a GT380

Post by jabcb »

The front drum brake for the 72 GT380 was actually previously used on the T350, which is a good bit lighter. Suzuki should have used the more powerful brake from the T500. The GT380 drum brake wasn’t that great back then, and now modern traffic has much better brakes.

Suzuki redesigned the exhausts on later GT380s for better cornering clearance. The frame attachment was moved to accommodate the redesigned pipes. You can mix & match but an adapter bracket is needed. Aftermarket expansion chambers can be a problem because they are not notched out for the stands.

You most likely will save a good bit of money by getting the best & most complete bike you can. Prices tend to be lower in the winter but a lot fewer bikes are available.

We built a 72 GT380 cafe. It has a 74 motor & 74-77 Higgspeed expansion chambers. Upgraded to a 72 GT550/GT750 4LS front brake which was surprisingly easy to do, but that brake is seriously expensive. Cornering clearance with the stock sidestand was horrible & we ended up using sidestand parts from other bikes.
The build topic: viewtopic.php?f=21&t=13036
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
lewis1956
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Suzuki 2-Strokes: 1970 T350 Now; TS250, GT380, TM400 Past
Location: Yorba Linda, CA

Re: Piece Build a GT380

Post by lewis1956 »

Appreciate the information! Will use it!!!!
sportston
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Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: Piece Build a GT380

Post by sportston »

I am partway through restoring my GT380M. It is worth getting a complete bike otherwise it makes another hassle trying to source lots of missing and expensive parts. Many parts are still available but can be very expensive, especially exhausts, crankshaft rebuilds, mudguards, fuel taps and fuel tank filler caps.
Good luck
lewis1956
On the street
Posts: 14
Joined: Sun Sep 03, 2017 7:03 am
Country: USA
Suzuki 2-Strokes: 1970 T350 Now; TS250, GT380, TM400 Past
Location: Yorba Linda, CA

Re: Piece Build a GT380

Post by lewis1956 »

Would love to find an old bike rather than piece parts, but not easy to find. I passed up on one about 5 years ago and could kick myself in the head.
Craig380
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Re: Piece Build a GT380

Post by Craig380 »

sportston wrote:I am partway through restoring my GT380M. It is worth getting a complete bike otherwise it makes another hassle trying to source lots of missing and expensive parts. Many parts are still available but can be very expensive, especially exhausts, crankshaft rebuilds, mudguards, fuel taps and fuel tank filler caps.
Good luck
Agreed -- 10 years ago you could get decent complete exhaust systems for £100, the later black side panels complete with decent original badges and stickers for £15, and sets of period chambers for £175 ... I know, because those are the prices I paid for all those parts on eBay in the mid-2000s.

I would echo Sportston's advice, and add that if possible, try to get a running bike. At least you know where you're starting from. The days of cheap parts and rebuilds have gone forever, so spending a little extra upfront is likely to save you a TON of cash later.

And if you ever see parts available anywhere, buy them. Doesn't matter if you don't need them immediately: you'll have them in reserve, or you can sell them on.
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
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ConnerVT
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Suzuki 2-Strokes: T500R (now), T500M (40 yrs ago)
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Re: Piece Build a GT380

Post by ConnerVT »

You all are overlooking a simple starting point - Buy a bike (complete or not) that has a clear title to the frame. Will save you thousands of headaches when you are at the point when you wish to actually ride it.
lewis1956
On the street
Posts: 14
Joined: Sun Sep 03, 2017 7:03 am
Country: USA
Suzuki 2-Strokes: 1970 T350 Now; TS250, GT380, TM400 Past
Location: Yorba Linda, CA

Re: Piece Build a GT380

Post by lewis1956 »

All great points. I have a T350 that did not have a title, and even though it took some work, getting a title and registration here in California was not too bad (unreal huh?????). Everything here is a royal pain in that regard, but my experience with the 350 wasn't too painful. If anyone knows or hears of a GT380, particularly a 72, please let me know. Thank you.
sportston
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Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: Piece Build a GT380

Post by sportston »

Stick an email alert for a GT380 search on ebay. Its not too hard to find a GT380 but, finding one cheap is another matter.
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