78 GS 750 Rebuild

[LarsKroghStea]

Awsome paint job! But you should consider to quit smoking

[Sam 78 GS750]

Thanks guys! It's extremely satisfying knowing that I did it myself. I definitely learned a lot, which translated into English means "I've made just about every mistake you possibly can while painting and had to fix them." Made it so the next tank I paint should go a lot smoother...

I think I'll leave the pinstripes off for now. I like the look of the tank without them, and can always add them later.

There are a bunch of odds and ends to take care of still. Mostly cosmetic/superficial but some performance items... Carbs seem super close as far as air/fuel mixture, but still need to be tweaked a bit. Also need to sync, but my bench sync doesn't seem too far off by the way it's running. I only did a static timing, so I need to bust out the timing light to get it spot on.

Still, it's running well enough that I'm going to hold off on all that to avoid idling/running while not under load. Once I'm confident the rings have seated, I'll play with all of that and really dial things in.

[pete]

Fantastic result Sam! Bet you're glad you were patient and took the time to get it right now

That tank looks awesome and glad to hear the test ride was a success too!

[limeex2]

Its a "holy sheet thats sweet" build! You have the patience of a saint with the paint.

[1978GS750E]

Looks great! You going to put the stripes back on it?

[dorkburger]

Nice! Congratulations on the test ride and the tank looks great.

[Sam 78 GS750]

Since then I got the new petcock on, put the tank on the bike, and fired her up. Started right up!

Seat's still at the upholsterer's shop, so I tied a couple of pillows together and took her around the block...I couldn't resist. Carbs need to be tweaked a bit, but it's running way better than I expected considering all that's been done to this bike.

[Sam 78 GS750]

OK, so pin head technique did the trick on the fish eyes. Took a bit to sand them down, but now it's smooth as glass. Got it all polished up. There are some imperfections still, but not bad for my first time painting a tank, and first time ever painting with a gun instead of spray cans. Ignore the bits of polish still on the tank...

20181217_083811 by samL9, on Flickr

20181217_083824 by samL9, on Flickr

[nvr2old]

If you go the route with the clear to fill your fish-eyes, make sure you have the hardener mixed with the clear before you do it. Sorry if that's a "duh" statement but I've seen people use that technique w/o the hardener and the drop of clear never dried. You might want to go with some 800 and a block, maybe even 600 to cut those fill-ins quickly..otherwise you'll never get it flat with 1000..then go over it with the 1000-1500-2000 again. I think I can still see 1000 grit scratches under you 2000. With a 2000 finish you should be able to see a glass smooth reflection. You may need to go over it with 1500 a bit more to get those 1000 grit scratches out and then finish up with the 2000. Looks like you have plenty of clear on there, so I wouldn't be afraid to take your 1000-1500-2000 over your body lines. That orange peel will stand out like a sore thumb on those areas if you don't. I'm proud of your patience and stick-to-it-ness..you're doing just fine.

[Sam 78 GS750]

ok, so compound around the fisheyes took it from dull with shiny dimples to shiny with shiny dimples... I'm gonna try to fill in with the pin head technique.
Also revealed that I have a little bit more sanding to do with 2000 before I'm ready to buff. It's shinier, but shiny with scratches still...

[Sam 78 GS750]

So I'm still at it. Got the tank scuffed up pretty good, and managed not to break through the clear in the process. Then I had a string of bad luck with the weather...super hot and close to 100% humidity every day for a stretch. Then all of a sudden it was too cold to paint. Finally hit a day 2 weeks ago where it was 68 and 50% humidity, so I got down to it.

I did get a couple of small runs, but nothing nearly as bad as last time. The solvent pop on the first round of clear didn't show up until a couple of days later, so this time I cut the runs down the next morning, and then lightly went over the entire tank with one of those 3M pads labeled "Ultra Fine: 800-1000 grit" just to open up the clear so it could breath.

Since then, I hit a couple of areas where the orange peel was kind of rough with 600, and then went over the entire tank with 1000>1500>2000 all using a soft block. Hard to tell for sure, but I think I got all the scratches from each previous grit with the next higher grit.

I masked off the seams and the area under the gas cap cover, and just stayed away from the body lines and corners... pretty much any area that broke through 1st when I was sanding the primer. Now I'm thinking of just going over the body lines lightly with the 2000 to just take the edge off the orange peel.

There are still some spots near edges that have orange peel and texture, but I'd rather live with those than burn through at this point. For the most part it's pretty flat though. I think that if I did sand enough at each grit to get the prior grit's scratches out, it should buff out very nicely!

These pics are all with the 1000 grit, I've taken it to 2000 since then...
20181110_150002 by samL9, on Flickr

The side I hadn't blocked yet, just lightly went over with the 3M pad.
20181110_150034 by samL9, on Flickr

not too bad off the bat, but a bit of orange peel. You can see the bike in the background of the reflection.
20181110_150105 by samL9, on Flickr

a bit closer.
20181110_150044 by samL9, on Flickr

I did get a couple of fisheyes this time around. They've diminished a bit more since I've sanded through to higher grits. Think they'll be noticeable after buffing out? I did google a bit, and some guys were showing that they mixed up a tiny batch of clear, and then filled them in with a drop of clear on a pin head. May just go that route and then sand a bit more with 2000 before buffing...
20181110_150128 by samL9, on Flickr

[nvr2old]

I know what you mean, Sam. I've been through exactly what you're going through. Just keep your sandpaper off the body lines or anywhere the clear might be thin after scuffing with the 600. As frustrating and scary as it is at this point, all will be replaced with a sense of satisfaction and accomplishment when you get your parts done. Be patient and focus and you'll be in great shape.

[Sam 78 GS750]

I'm also worried about the body lines and down by the seams. That's where I always broke through first when sanding the primer... I want to make sure it's scuffed up enough so that the next coats stick, but not sand to the point where I break through. I think a very gentle touch is called for here.

Who knew painting could be such a heartbreaking enterprise? I feel like I'm so close right now. If I had to take it back down again, I think it would feel like my first breakup.

[nvr2old]

Better to be safe then sorry at this point, Sam. As long as you have the entire surface scuffed up pretty well with the 600, just go with that and start the clear process again. The next round should fill in whatever orange peel is left.

[Sam 78 GS750]

As a bit of a sanity check, I put water on the tank to get an idea of what it would look like with more clear over what's there. I could still see the texture and orange peel under the layer of water, but only if I looked really closely.

Is that a valid check/approximation?