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1972 Suzuki GT750

38K views 118 replies 35 participants last post by  bweighmaster 
#1 ·
Here is my restoration project. A 1972 Suzuki GT750: 6983 origional miles, Candy Lavender (pink) original paint. I have a Florida Antique tag on it and JUST got it running right today. I am now going to mov to the brakes, then suspension, electronics and then cosmetics. This has been in my family since it was bought new in 1972 by my grandfather in PA. Then my great uncle had it for a decade or so, then my uncle had it for a number of years and now it has been passed down to me afte sitting under a tarp in my uncle's garage for close to 8 years. Please give me your ideas, opinions and any tips you might have. Thanks, enjoy!
 

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#71 ·
Jkot mine is also blue :D in regards to the chain yes I will have to replace it but haven't yet. You should check out http://www.ironpony.com/ . This is where I got the points and condensers and they even had them in stock! I just ordered them over the phone and they are shipping them to me. I don't know where you're located but that shop is in Ohio. I've always had good luck with them, they've done work on my Yamaha for me and were lifesavers. If you find out the chain specs let me know as well as that's something else on my list...once it's running of course!
 
#72 ·
JDOTPDOT84, thank you for the link. I sent them an email. BTW, I know a guy in Colorado that makes transistorized ignitions and he just started making them for 2-stroke tripples. I bought one years ago for my 75 CB750-4 and now ordered one for the GT750. It just plugs in and uses all existing points, etc. Takes some strain off the points so they last longer and adds some performance. My GT750 starts and runs fine but like the idea of saving the points and getting a better spark. Let me know if you are interested and I'll get the info for you.

CHAZZ, I have the manual and did not see a part number but will go back and look.

Thanks a bunch.
 
#73 ·
Jkot,
The manual I have I actually copied from a university years ago. It had ever torque value for every bolt on the bike along with part numbers and such. I just can't find the freaking thing in my garage. Its in a nice folder and just cant locate it. I am thinking I might have to go find another one. For some reason I am thinking 508 and 52 links for some reason
 
#74 ·
New points/condensers arrived today, replaced all of those, nothing like messing with screws that haven't been touched in 30 years to brighten your day! I have spark now like I should, after replacing the first set it popped like it thought about starting, after replacing them all, nothing. However, they're not yet gapped properly so doing that tomorrow (don't have a feeler gauge), and hoping to see some progress....
 
#78 ·
Thanks Chazz, well the petcock/screen are all new (never had gas through it), carbs were rebuilt before I got the bike by my father, but not adjusted, so I'd have to think there in lies the problem. It will idle fine @ 1000 rpm or so, tomorrow I'm draining the gas out (not horrible but not fresh either) and replace it with fresh gas, i had some old oil come out of the exhaust pipes that have been in there for who knows how long, I know it was old b/c it was extremely dirty and I put all new in it. I adjusted the smaller screws on the carbs all the way in and back out 1 1/2 turns per the book I have. I'm not sure where the ones you can do by hand should be, or if the 1 1/2 turns is even enough.
 
#83 ·
Ok nevermind figured it out...wow cone filters for the win! When I get it going I'm seeing new 2 cycle oil coming out of the exhaust, not a steady stream by any means but obviously none should be. I'm thinking perhaps too much is getting injected causing it to run too rich which would make sense as when I try to give it gas it wants to die, is there a way to adjust the injectors and if so, any recommendations on settings?
 
#84 ·
1972 GT750 also

Hi nice bike! I got one just like it that I'm trying to get running after sitting for 15 years without running. Of course it was running when I put it away. I've had it for the 40 years of her life, and am threatening to get it going again. I would like to ask for some advice, but am unable to find the spot to post. For now I'm using jumper cables from the car to turn it over. I'm not getting spark, and the fan runs all the time.
 
#85 ·
JP I do not know off the top of my head if those are adjustable or not. But yeah you should not have oil coming out of the exhaust.

Cira. Where in Mid Michigan are you? I too am in Michigan just north of Jackson. The fan should not be running but that could just be a bad sensor. The no spark is probably points or condensors are shot.
 
#87 ·
Well I'm thinking reason for the oil is it's too rich, and when I'm twisting on the throttle the motor isn't revving, but it is activating the oil pump so there's excess oil which is not burning and running out of the exhaust. Cira, pull the clutch cover off and check your points gap first, if they're not sparking try cleaning them with some fine grit sandpaper, if that doesn't work chances are the condensers are weak/shot. That's what was happening with mine. I put new points and condensers in and it fixed that problem. I ordered a kit with all 6 components for 50 bucks shipped to my door. I'd never messed with them at all and figured it out within about an hour and 20 minutes. The main problem I had was loosening screws that hadn't been touched in 20+ years. If you have the suzuki repair kit use the screwdriver that's included, I found it worked best. Let us know your results.
 
#90 ·
Thanks Chazz, I thought so myself, then the only other thing I could think of was that when opening the throttle more, it would open up the oil pump more anticipating the increased RPM. I pulled the inspection cover off and when you twist the throttle the lever on the oil pump opens more and more, so I was thinking perhaps as that opened more it was allowing the oil regardless of the fact that the RPM's weren't increasing, there again I might be way off though. I found a little shop here that specializes on vintage bikes and dropped if off yesterday, they're supposed to look at it tomorrow so hoping for some news that's not too painful.
 
#92 ·
Hi Chazz, finally got it back and now it's running like a top! I talked to the guy that worked on it, he said it was the timing and 2 of the carbs had blockages in the smallest part of the jet, they dipped them twice and wound up having to pull it out, he said it was "some sort of fibrous material" so no idea on how....he wound up putting all new fuel lines and vacuum line on, threw some hardware on so the seat will work, set the timing, cleaned the carbs and even gave me half a tank of gas all for $200!! When they called me and said "we have 12 hours in it but are only charging you for 10" my stomach dropped as most shops have a labor rate of hie $60-mid $70 range, so roughly $20 /hr after all said and done. So now the process of cleaning/restoring begins....
 
#95 ·
I think my oil pump is draining into my case as it just sits. Has anyone seen this problem before? Its one smokin' dude when I fire her up after a few weeks of sitting and the oil tank is noticeably lower. would it just be an adjustment or do I have an oil pump problem?
 
#97 ·
I tried to get a pic on here. Not smart enough to do it i guess.
I looked yesterday and sure enough, my oil tank is close to empty. It was just above the site glass when I parked it. So the oil is going by the pump somehow. I'll finish the carbs tomorrow then start messing with the oil pump. Gotta be a check valve or something like that leaking.
 
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