Restoring a '75 GT750!

Photos and progress of your restorations, even bikes you had but no longer own.

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Toast
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Suzuki 2-Strokes: '01 Dr650, '75 GT750

Re: Restoring a '75 GT750!

Post by Toast »

I've got the same question, I've seen both 3/4 and 1/4 recommended. What is the best way to judge if you are at the right mixture? I figure there should be a better way than analyzing plug color...
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RING_DING
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Re: Restoring a '75 GT750!

Post by RING_DING »

Yes its a bit confusing. Even though they look the same, there were some subtle differences between carbs on the L model and the later M/A/B models. I believe the 1/4 turn is for the carbs on the L model. For your M model 3/4 turn is the correct standard setting.
1973 Suzuki GT750K with Sidecar - Bonneville 2020
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jabcb
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Re: Restoring a '75 GT750!

Post by jabcb »

Carb specs for the L & M models are in service bulletin Specification-6:
http://www.ozebook.com/compendium/techb ... %206-9.pdf
Has same settings as ring-ding mentioned.
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tz375
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Re: Restoring a '75 GT750!

Post by tz375 »

L was the first year with those carbs and had different throttle plate, larger pilot jets and the slow speed mixture screw at 1/4 turn. M and later changed to 110 throttle plate, #45 pilots and 3/4 turn on those screws. The throttle plate number relates to the angle it sits at when closed and if I understood it correctly, changing the angle changes teh way that it uncovers the bleed holes and therefore the way it allows both air and fuel in.

Plug readings are not a lot of use for setting slow jets. The traditional way is to turn them in 1/4 turn at a time and see how it runs and then out 1/4 turn at a time and find the setting with the highest idle speed.

On those carbs, turning the screw IN makes it leaner and OUT for richer. That is the opposite to AMAL style slide carbs.

I would set them at 3/4 and if it runs fine, great. Leave it alone and run it. :)
Toast
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Suzuki 2-Strokes: '01 Dr650, '75 GT750

Re: Restoring a '75 GT750!

Post by Toast »

Hey guys, thanks for the tips. I set the pilot scews to the 3/4 setting and rode it around a bit. Seemed to run fairly well. One thing I did notice was the RPM appeared to return to idle a little slower than it should... not sure. I'll have to post a video once I run it again. Anyway, I ran it enough to be satisfied that the engine/transmission are in OK shape so I'm dismantling it again to do some cosmetic work. I'd like to polish the engine cases but don't have much experience with it. Is there a good thread on here that covers that? Also, were the buffalo cases covered with any clear coat from the factory?
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Re: Restoring a '75 GT750!

Post by pearljam724 »

No clear. It depends how great of a result you're shooting for. If you want mirror finish. Start with a brillo and degreaser to get the heavy tarnish and gunk off. Then wet sand starting with 4-6 hundred for scratches. Work your way up to 2k grit. A ton of work, but amazing results. If you want fast and easy. With pretty good results. Use a 2" wired wheel on drill. Then polish with a solid polish stick on a high speed drill and polish bit. Harbor freight sells a great polishing kit for $20. Quick and nice. Contrary, to what some people say. You can use the medium course wired wheel on zinc fasteners also. Which ever you choose. Dont use a wired cup. Use a disc shaped. Use the wheel or sand in the same direction or you get swirls and other imperfections. Turns out pretty.
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RING_DING
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Re: Restoring a '75 GT750!

Post by RING_DING »

Regarding polishing the cases I found this article very helpful:
http://www.cbxclub.com/davespage/mcy84-1.html" onclick="window.open(this.href);return false;
1973 Suzuki GT750K with Sidecar - Bonneville 2020
Toast
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Suzuki 2-Strokes: '01 Dr650, '75 GT750

Re: Restoring a '75 GT750!

Post by Toast »

So even though my posting on this forum hasn't made much progress, I have made some with the bike. I started to get into some polishing starting with my starter cover. Figured if I messed up nobody will really see it. I decided to get the polishing kit from Harbor Freight and go down that route. I was pleased with how things came out. Not mirror finish but that's not what I was shooting for with this bike.

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I also got some work done on the battery box... rusted of course. A little time in the blasting cabinet and primer is a good start.

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I also tried blasting the rusted turn indicator stalks. Chrome doesn't submit to blasting very well... :( Guess I'll tool around for some on ebay.

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So amid the cosmetic work, I noticed a small amount of oil leaking from the drain under the impeller cover. I did some researching and made sure my oil level was correct (which it wasn't) but doing this didn't change the oil leak. My guess is that the water pump 0-rings are leaking. I was a little bit worried about getting the pump out after reading all this stuff about splitting cases or drilling them just to get it out :wth: ! Not what I wanted. Anyways, I was really excited when the pump came out tonight without much fuss (the impeller was actually harder to get off) :D . Any suggestions on where to purchase o-rings or ideas on what else could be leaking? I'm not really sure how leaking o-rings would cause oil to flow out the drain under the impeller cover (not sure how they connect) but that's what I've been reading.

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pearljam724
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Re: Restoring a '75 GT750!

Post by pearljam724 »

For O rings. Harbor Freight sells a huge assortment of metric o rings for 10 bucks. They also sell packages of large rings. For the signal stalks and any other type of polishing. I recently discovered how great rubber polishing discs work. Awesome on old rusty chrome, etc. It will leave behind tiny divets from major pits of course. But rubber works amazingly well. Saving a ton of time compared to wet sanding. Just polish with the compounds after using the rubber discs. Unlike the fine to medium course wire wheel. Using rubber doesn't leave the slightest scratches behind. They are also much cheaper and surprisingly outlast any other type of bits. From here, those signal stalks look like an easy clean up.
Last edited by pearljam724 on Fri Feb 01, 2013 2:18 am, edited 1 time in total.
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Toast
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Suzuki 2-Strokes: '01 Dr650, '75 GT750

Re: Restoring a '75 GT750!

Post by Toast »

pearljam724 wrote:For O rings. Harbor Freight sells a huge assortment of metric o rings for 10 bucks. They also sell packages of large rings. For the mirror stalks and any other type of polishing. I recently discovered how great rubber polishing discs work. Awesome on old rusty chrome, etc. It will leave behind tiny divets from major pits of course. But rubber works amazingly well. Saving a ton of time compared to wet sanding. Just polish with the compounds after using the rubber discs. Unlike the fine to medium course wire wheel. Using rubber doesn't leave the slightest scratches behind. They are also much cheaper and surprisingly outlast any other type of bits. From here, those mirror stalks look like an easy clean up.
Do you use the rubber polishing disk directly on the item (no compound etc)? Any recommendations on places of purchase? Thanks for the tip, I was about to get a wire wheel but the rubber disc sounds neat.
pearljam724
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Re: Restoring a '75 GT750!

Post by pearljam724 »

They only make them for dremel sized bits. You can get 1 or 2 in a large polish assortment kit. Ive never seen them sold individually in a store. But, they work so well I recently bought a 25 pack from a seller on Ebay for $6.50. They come in different grits. I found the medium gray colored work great. Don't use polish with them. Use your Harbor frieght polish kit and white compound after you've used the rubber disks. They're great for working in tight crevices too. That you cant get to by other methods. The key to being most effective whether you use wire or rubber is drill speed. Not too fast or slow. You can't sand or sand blast chrome in order to polish. But, you can with rubber or a compound by its self. Check out this item I found on eBay: http://pages.ebay.com/link/?nav=item.vi ... 0866529329" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
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RING_DING
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Re: Restoring a '75 GT750!

Post by RING_DING »

Hi Toast, I have a box full of old turn signals and I am sure there are some decent stalks in there. If your polishing efforts don't work out on those rusted stalks just let me know and I'll see what I can dig out for you.
Regarding your water pump, you were very lucky that it came out so easily! There's a ton of info on this forum about water pump overhaul/renewal. It is possible to refurb the water pump but as they say "results may vary". Check this out:
viewtopic.php?f=9&t=4465&start=30" onclick="window.open(this.href);return false;
I opted to go for a complete replacement for peace of mind. They are available from Suzuki as a complete unit (except for the impeller and circlips). Get a new gasket for the water pump cover while you are at it.
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tz375
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Re: Restoring a '75 GT750!

Post by tz375 »

Toast, the O rings are readily available but in all probability, it's the top oil seal that is shot. They are available from any seal supplier and if you can't find them, I think that Suzuki Smokin Allan has some for sale. If not, I have them in stock for pump reconditioning.

Which reminds me, I need to get some more cores.
Toast
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Re: Restoring a '75 GT750!

Post by Toast »

After waiting for a good discount to show up, I bought H.Freights motorcycle lift. I've been needing something for this project and my DR. So far I have not complaints with it... we'll see how it holds up :| . This enabled me to remove a lot of stuff (both wheel assys, swing arm, kickstand, etc). Some of these things I'm hoping to paint. I wish I had the budget to powder coat everything but that's probably not going to happen. Can anybody recommend a good spray-can paint that would match the factory black found on the frame? I'll be painting some of the small components. I know the importance of good prep and multiple coats when painting but am looking for a paint that will match the black and hold up well. Also, how much life (percentage) is left on these brake pads? Thanks guys, I've been appreciating all the help from the people on this site.

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pearljam724
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Re: Restoring a '75 GT750!

Post by pearljam724 »

Pads dont appear to be bad. I have found only one spray paint that I would trust its durability on a frame. Thats tractor paint. You can buy it at Tractor Supply. Rattle paint will not be durable enough. Good prep or not. I tried many times to prove that advice wrong. But, failed. Its one thing to rattle paint bolt on items. If the paint fails in a short time. You can easily take the part off and paint it again. The frame is something you only want to do once. If you talk to the right guy, save him all the prep and other hassles. You can have a paint shop do it for around 300 I would think. Consider a brush on, 2 part epoxy to increase durability and save money. As soon as heat or sun hits rattle paint. It will fall off or fade. There is not enough UV protection in it. I dont suggest it over automotive paint. But, if you use the tractor paint. Have a can of carb cleaner with the straw tip by your side at all times. You'll need to constantly clean the rattle can tip within 30 seconds of using it. The paint dries that hard.
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