78 GS750 engine overhaul on the Cheap!

[Bobbys 94]

What are you going to do?

I've had good success with soaking rusty parts in phosphoric acid. Kleen Strip Etch and Prep, as sold by Home Depot is a good option. You could fill up a plastic garbage can, dump in a 2-3 of gallons, fill with water, and drop in the frame. After a week the frame will be clean. As long as the metal erosion from rust isn't too bad, that may do it...

This is what I was talking about on the corrosion that could be coming from within the tubes of the frame. The pic shows where the right rear passenger peg bracket would have been welded to the tube. As you can see the corrosion is for the most part coming from the inside. I've decided that this frame is Junk just like the 4 carburetors were. I have a really nice donor 1979 GS750L with a perfect frame and engine. Many mods will have to be done to the L frame to convert it to the 1978 GS750 frame but I'm up for the task.

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[Bobbys 94]

What are you going to do?

I've had good success with soaking rusty parts in phosphoric acid. Kleen Strip Etch and Prep, as sold by Home Depot is a good option. You could fill up a plastic garbage can, dump in a 2-3 of gallons, fill with water, and drop in the frame. After a week the frame will be clean. As long as the metal erosion from rust isn't too bad, that may do it...

Ed, the frame will be powder coated, so it will be blasted and baked at 420 degrees for 30 minutes prior to the powder process which will then bake for approx. 25 minutes at 420 after powder. What I'm concerned with is "What damage has already been done to the inside of the tubes of the frame"

[Nessism]

What are you going to do?

I've had good success with soaking rusty parts in phosphoric acid. Kleen Strip Etch and Prep, as sold by Home Depot is a good option. You could fill up a plastic garbage can, dump in a 2-3 of gallons, fill with water, and drop in the frame. After a week the frame will be clean. As long as the metal erosion from rust isn't too bad, that may do it...

[Bobbys 94]

No doubt, the bare frame, no front or rear parts got to be very easily lifted off. Glad it worked well for you. Glad you got your priorities straight too, granddaughters 4 wheeler got to come first... Same with paint, priorities again, if granddaughter wants granddads bike pink,,,, I don't see a question. For me "I" like a nice OEM color, Yours seems to be a "79" OEM color, (Pure Red) "79" were Pure Red and Lovelock Maroon. "78" colors were Burgundy or Black Bluing (actually dark blue), and the "77" colors Gypsi Red and Potomic Blue. My opinion, for these first gen. GS750's the "77" colors were by far the best. I'm betting I'm pretty near the bottom of that priority list... If not, I should be.... Keep it up..., looking good.

Some variation of Black is at the top of the list.

Having completed the initial teardown I've come to the conclusion that, my frame has had a lil water (condensation) trapped inside for a very long time....I live in Texas and so did this GS for the last 40 or so years. High humidity Always. About 1 to 2 oz's dripped out of the top rear tubes that are just crimped on the back end. Upon further investigation I had more slowly seeping out of other small spots on the frame. I've attached a pic of the swingarm. Notice the rust/corrosion on the top. I'm thinking the inside is probably as corroded if not more. It looks like hammer marks but is actually what it looked like after I removed the top rust layer with a wire brush.
I've found that on All of my machines, "If you don't keep them in a climate controlled environment or ride them often, they get wet, inside and out"
I have not noticed any weep holes so I'm guessing no one has them. Note: At my place a weep hole would only last a day or so before a dobber filled it.

Swingarm at the least will be donated to me by my other GS.

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[rphillips]

No doubt, the bare frame, no front or rear parts got to be very easily lifted off. Glad it worked well for you. Glad you got your priorities straight too, granddaughters 4 wheeler got to come first... Same with paint, priorities again, if granddaughter wants granddads bike pink,,,, I don't see a question. For me "I" like a nice OEM color, Yours seems to be a "79" OEM color, (Pure Red) "79" were Pure Red and Lovelock Maroon. "78" colors were Burgundy or Black Bluing (actually dark blue), and the "77" colors Gypsi Red and Potomic Blue. My opinion, for these first gen. GS750's the "77" colors were by far the best. I'm betting I'm pretty near the bottom of that priority list... If not, I should be.... Keep it up..., looking good.

[Bobbys 94]

I may be on to something here. Still trying to figure out what direction I want to go with this project before I take all components to powder coat. What do ya think about this route??

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[Bobbys 94]

Read about lifting the frame off the eng. from laying on the side several times. I've not tried it, I've always had somebody around and we just slid the eng. out the side... Seems you've got it figured out, Keep it up.

It's the only way to go IMHO, as long as it's just a frame and engine. I would not have attempted it with the front and back components still attached. I wanted to try and not scratch any of the work I'd already done to the engine. Doing it this way, I don't think any part of the frame touched any part of the engine during the removal process.

[Bobbys 94]

Gotta keep my priorities straight. My granddaughter has been bugging me to get her 4 wheeler running so that's exactly what I did after the engine removal.

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[rphillips]

Read about lifting the frame off the eng. from laying on the side several times. I've not tried it, I've always had somebody around and we just slid the eng. out the side... Seems you've got it figured out, Keep it up.

[Bobbys 94]

Glad I purchased the engine stand that has the u shaped support base, it fit well under my lift. And the lift gives extra support under the engine.

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[Bobbys 94]

Very stable platform to mount your engine to.

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[Bobbys 94]

Close up of the mounting of the engine to the stand. Heavy modifications had to be done to the mount fingers on the stand, all 4 of the 1/2" holes had to be re-drilled further in and 2 of them had to be cut 1 1/2" shorter. Worked very well after the mods.

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[Bobbys 94]

While on the lift I attached the mount plates and bolts for the engine stand.

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[Bobbys 94]

I then turned it on it's side to remove the frame from the engine. It took very little effort on my part to lift the frame away from the engine. Actually, I dropped the lift down with the frame supported by the rafters, Easy Peasy.

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[Bobbys 94]

Trying to use as little Physical labor as possible to do the engine removal. After the front and back components were removed I needed to tie the frame to the rafters to support it while I let the lift down to remove the jack and blocks.

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