New to 2 Strokes and My first GT-750

General discussion about Street two-stroke Suzuki motorcycles.

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acruz
On the street
Posts: 11
Joined: Sat Apr 15, 2017 2:20 pm
Country: united states
Suzuki 2-Strokes: 1972 GT750
Location: Bay Area

New to 2 Strokes and My first GT-750

Post by acruz »

Hi All,
I'm Arnold. I live in Northern California. I just got delivery of a 1972 GT750 in Lavender a week ago and i'm a little intimidated by it. I have worked on mostly Honda bikes for for the past 3 years, but I came across this bike a month ago and wanted to see if I could get it running. The bike has only about 3200 miles on the engine and has been sitting in a garage for the past 12 years. No attempt to start it by the previous owner. It was a bike handed down the seller's grandfather and was never ridden after being placed in the garage. Being new to this type of engine and the fact that the engine sat so long, I wanted to ask you guys where to start in trying to get it started. I haven't tried to crank it over or see if the engine is turning freely. If you guys can recommend a procedure or even previous threads on how to approach getting this engine started, I would greatly appreciate it.
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1972 GT750 Lavender
1972 GT550 Aztec gold
1969 Honda CB750 Blue Green
1969 Honda CB750 Ruby Red
1969 Honda CB750 x4 projects
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tz375
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Location: Illinois

Re: New to 2 Strokes and My first GT-750

Post by tz375 »

Old age can be as cruel to bikes as it is to people.

That's a nice bike and a very early one, so it would be nice to save it.

If it were mine, I would probably start by removing the tank and fuel tap and clean them out. While they were off, I would remove the carbs to clean out whatever is in there.

While the carbs are off, I would pour either diesel or something similar - maybe 50/50 fuel/oil into the bottom end to wet the seals and perhaps swell them. After sitting for so long the bottom end may be just fine or it maybe full of rust, so let's hope for the best. Turn it over by hand (well by foot) every couple of days.

If the diesel keeps vanishing, the seals are shot. Make sure you have a large catch tray underneath - just in case

I'd replace the plugs and clean the points and replace them if necessary and set the points gaps and timing.

While the carbs are off, check the airbox for critters, wasps etc and get a new battery. Clean up the battery connections and then spray WD40 into the switches and work them back and forth to clean the contacts. Test compression on all three cylinders.

Check the exhausts for wasps and critters too. pump up the tires and check the brakes and see if the chain is rusted solid.

Then drain the crankcases, check that the electrics work and you have sparks. Refit the carbs and rig up a safe temporary fuel supply and see if it fires up.

If it does and you like what you hear, clean it up and replace consumables (tires, cables, chain etc)
acruz
On the street
Posts: 11
Joined: Sat Apr 15, 2017 2:20 pm
Country: united states
Suzuki 2-Strokes: 1972 GT750
Location: Bay Area

Re: New to 2 Strokes and My first GT-750

Post by acruz »

Thanks for the tips! I checked the gas tank and it looks pretty clean on the inside. there are a few smooth dents but it looks okay. I will need to replace the rubber carb manifolds as they appear cracked and dry. The question I have is after I remove the carbs, you recommended: "While the carbs are off, I would pour either diesel or something similar - maybe 50/50 fuel/oil into the bottom end to wet the seals and perhaps swell them. After sitting for so long the bottom end may be just fine or it maybe full of rust, so let's hope for the best. Turn it over by hand (well by foot) every couple of days." My question is how do I put the diesel solution into the engine? Would it go through where the oil is placed? Can i use Mystery Marvel Oil? Sorry for my ignorance in advance.

Thanks
aRnold
1972 GT750 Lavender
1972 GT550 Aztec gold
1969 Honda CB750 Blue Green
1969 Honda CB750 Ruby Red
1969 Honda CB750 x4 projects
rngdng
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Location: Blythewood, SC, USA

Re: New to 2 Strokes and My first GT-750

Post by rngdng »

Fill the crankcase from the intake ports.


Lane
If you stroke it more than twice; you're playing with it.

Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
Craig380
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Location: Manchester, UK

Re: New to 2 Strokes and My first GT-750

Post by Craig380 »

Like TZ & rngdng said, pour the 50/50 fuel / 2-stroke oil mix (or diesel) in via the carb inlet stubs on the cylinders. Remove the spark plugs and pour a spoon or two down the plug holes too. Leave it overnight, then gently push down the kickstart lever to ease the engine over a few times. Then leave overnight again, and repeat for a couple days while you do all the other checks and tasks that you've assigned yourself from TZ's list :wink:

With this process, you're giving the motor a good chance of waking from its hibernation intact .... good luck and keep us posted.
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
acruz
On the street
Posts: 11
Joined: Sat Apr 15, 2017 2:20 pm
Country: united states
Suzuki 2-Strokes: 1972 GT750
Location: Bay Area

Re: New to 2 Strokes and My first GT-750

Post by acruz »

Would you guys ever use Mystery Marvel Oil instead of diesel fuel. I think it's a mixture of fuel and oil- no one really knows. Apparently you can use it in both fuel and in oil and in 2 strokes as well. I have had good experience in other motorcycle engines.
1972 GT750 Lavender
1972 GT550 Aztec gold
1969 Honda CB750 Blue Green
1969 Honda CB750 Ruby Red
1969 Honda CB750 x4 projects
rngdng
AMA Superbike
Posts: 1769
Joined: Tue Oct 14, 2008 6:47 pm
Location: Blythewood, SC, USA

Re: New to 2 Strokes and My first GT-750

Post by rngdng »

I've seen that stuff in the auto parts stores forever but have no experience with it.



Lane
If you stroke it more than twice; you're playing with it.

Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
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Alan H
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Joined: Thu Feb 16, 2012 11:50 am
Country: England
Suzuki 2-Strokes: 4 x GT550s - J, M, A, B.
Location: The Republic of South Yorkshire

Re: New to 2 Strokes and My first GT-750

Post by Alan H »

More details of the diesel trick on page 5 near the bottom.
http://www.kettleclinic.co.uk/kcforum/v ... g&start=40" onclick="window.open(this.href);return false;
Done it twice on two engines and it seems to work.
3000 miles on the first one and about 1500 (high revving) miles on t'other.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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