78 GS 750 Rebuild

[Sam 78 GS750]

So I've been off the forums for a few years before coming back in October and giving some details about how my bike got to be in the sad, sad state it's in...

http://www.thegsresources.com/_forum/showthread.php?227159-Returning-Member-Long-time-gone

The short version is that a 9000 mile trip a few years ago left her limping and with a horrible oil leak. I got home, parked her, and haven't touched her since (other a spray down with a thick coat of WD-40. Yeah, I guess I'm "that guy"). I've finally decided to get to work, and bring this old girl back to life.

Here's some photos showing just how bad it is. Hopefully as this thread progresses, it'll turn into a nice before and after, and also serve as yet another tutorial on the forums as I show my progress and hopefully get some advice when I inevitably run into some tricky situations....

Here's what I'm starting with (minus the carbs, which I already rebuilt)


Doesn't look too bad, right? Let's get a little closer



Pretty dirty in there Rust all over the place... Oxidation where it used to be so shiny.
More rust... More grease, grit, and grime Peeled paint, and more rust.
Scraped peeling paint with iron oxide underneath Fe2O3 on what was a nice x-ring chain Left on reserve the last time I rode her

[Sam 78 GS750]

Lovely seat pan Some shrubbery in there too... paint peeling around the gas cap

Some chips in the tank


On top of being pretty filthy right now there's also the massive oil leak from the head gasket, along with some mechanical problems including what seems like a fried stator...so all I can do is tear her down before I build her up.

On to it...

Already took the carbs off to rebuild them and left them off. Air box too. Took off the tank and seat.



Next off was the exhaust. Surprisingly, the header bolts came out nice and easy.



These pipes have seen better days...

[Sam 78 GS750]

Behind the pipes isn't too pretty either.



The clutch adjuster/sprocket cover came off next. This actually took me the longest to take off out of everything. Damn phillips head screws stripped out. I think an allen bolt kit is definitely in order... Anybody have recommendations for a supplier?



First time ever draining the oil on this bike where I didn't have to worry about it getting all over the pipes...



And we're almost there.



Almost forgot to disconnect this guy...


Next was disconnecting the random wires coming off the engine (including burnt ones going from the stator to the R/R...)



Jack up the engine a smidge to take the weight off the mounts a bit before disconnecting them.



After the mounting bolts are removed, jack the engine up over the frame, then pull it up and out the right side. Brought a 6 pack to bribe my brother in law to help me pick it up out if the frame. This is as far as I got so far, but not too bad for one afternoon.


I already have a decent amount of work into the bike from a few years ago, so it's not gonna be a completely from scratch rebuild... I already put in a Dyna ignition and Accel coils, Progressive shocks and fork springs, along with a bunch of other odds and ends that I can't think of right now... All the polishing I did on the aluminum went to hell, but that's what I get for my neglect...

For now I plan to rebuild the engine, paint the frame, and do all the basic maintenance. That should be enough to get her back on the road so I can get some riding in this season. Everything else that doesn't require a complete disassemble I can do section by section when I have the time/money to spare.

[Sam 78 GS750]

Been pretty busy, but I got to work on the engine a little bit today finally... got the head and cylinders off without too much trouble. The pistons have a lot of carbon on top, but under the rings looks decent. Some of the head studs are pretty rusted and when I pulled the head and jugs off a decent amount of rust powdered off and fell into the crank along with other gunk and garbage... I'm hoping I can clean it all out without having to split the cases. I've never even been this deep in my engine before (had the cams out, that's about it). I'm pretty confident with the top end so far though...easy enough. The bottom end with all it's tiny bits and pieces is kind of intimidating... anyway, I'll post some pics in a few.

[cowboyup3371]

You can get allen headed screws at Ace Hardware or through Z1 for example

[William Groebe]

Don't be too intimidated by the bottom end. Just follow the procedure in the manual. Everything comes apart and goes back together without too much fuss.
Good luck with the cleanup.

[Sand_fiend]

the bottom end in my opinion is easier then the top end. take your time and follow the book. it's really not that hard. you can also drop the bottom pan and flush the motor out from the top side.

[mikerophone]

Nice - Looks like you are off to a great start.

All of your photos have a strange blue cast to them - a filter on your phone perhaps? Kinda strange, makes it look all the more dirty

[Sam 78 GS750]

the bottom end in my opinion is easier then the top end. take your time and follow the book. it's really not that hard. you can also drop the bottom pan and flush the motor out from the top side.

That's definitely reassuring. Part of me thinks while I'm in there do it all, do it right, do it once, and the other part says if it ain't broke don't fix it. There's nothing wrong with the bottom end, and nothing's leaking for me to want to take it apart. Plus I've heard some horror stories of guys splitting the cases just because while they were doing a top end rebuild and ending up with oil leaks they never had before. On the other hand, who knows how long I have before a 40 year old seal fails...it would be a shame to have to do the same work twice.

You can get allen headed screws at Ace Hardware or through Z1 for example

I'll check them out...I'll have to check the size/pitch of the screws in the parts fiche. I saw some kits on ebay, but I'm thinking just knowing the sizes I need and picking from an assortment would probably be cheaper...

Anyway, some pics from yesterday... (the blue tint is from the lighting I think...my phone is old and the camera doesn't have a flash)

Valve cover gasket by samL9, on Flickr
Valve cover gasket almost came off in one piece.



camchain by samL9, on Flickr
Still pretty clean in there from when I had the cams out a few years back...

cams out by samL9, on Flickr
Cams out

head 2 by samL9, on Flickr
Head off...the valves look pretty nasty. A lot of carbon and a bit of rust too. I guess a head gasket leak lets water in, not just oil out, huh?

studs by samL9, on Flickr
This is how she sits right now.

studs 3 by samL9, on Flickr
Piston a bit closer


studs 6 by samL9, on Flickr
Not too bad below the rings.

Work Area engine apart by samL9, on Flickr
The workshop. (yes, that's the corner of my living room... my girl's awesome!)

[Sam 78 GS750]

Nothing much to report... Disconnected the pistons, and took the valves out of the head. Also cleaned the head and cylinders up a bit with some simple green and dawn.

[Sam 78 GS750]

Still not too much happening. Between work and night classes, this is gonna be a slow rebuild. As long as I keep making progress a little at a time though.
I've been cleaning up bits from the top end here and there before I dig in to the bottom.
A before and after shot of the pistons:

Piston B4 and After by samL9, on Flickr

That was a lot of scrubbing with a wire brush and a long dip in some Berryman's later... More soon to follow.

[azr]

Where exactly are you doing all your parts cleaning???? good luck with the rebuild, looks like you're not shy from wrenching which is great.

[eil]

Thanks for keeping us up to date. I like reading rebuild threads. Looks like fun.

[Sam 78 GS750]

Where exactly are you doing all your parts cleaning???? good luck with the rebuild, looks like you're not shy from wrenching which is great.

I don't have a garage or anywhere proper to work on things, so I'm doing it in my living room... Lay down a lot of plastic, open all the windows, and set up a giant fan in one window as an exhaust fan. I set up a table in a storage room I have off my living room, so as pieces come off the motor, they get a cleaning and go on the table. When I'm done working for the day, take down all the plastic, and put everything away. Far from ideal, but it works. My girl is tolerating it for now. She says "as long as you get your bike fixed that's all that matters." I'm trying to finish up before that turns into "When are you going to get that *%$^^#@ engine out of our living room!"
Definitely not shy from wrenching, but I don't always know what I'm doing lol. This site is a huge help!

Thanks for keeping us up to date. I like reading rebuild threads. Looks like fun.

It's been fun so far. I love reading rebuild threads too. I'm following a few on the forums here, and they give me inspiration, guidance, and sometimes a kick in the butt to get moving when I need it...

[Sam 78 GS750]

More details on my "workshop"

I started with this as my work area. (corner of my living room)
work area 2 by samL9, on Flickr

But as the disassembly progressed, the parts started to spread out...

...so I went through my little hobbit hole
hobbit hole door by samL9, on Flickr


And set this up.
hobbit hole 2 by samL9, on Flickr
hobbit hole by samL9, on Flickr

Now, as parts come off the engine they get a quick scrub down then I duck down and squeeze through the tiny door and lay them out on this table. Far from ideal, but I'm working with what I've got.

This is how she sits right now.
lower case no oilpan by samL9, on Flickr

The pics make it look a lot cleaner that it actually is... I've got my work cut out for me when it comes to cleaning this thing up and getting ready for paint! Speaking of which, if any paint gurus in the central Jersey area want to lend their guidance, it would be much appreciated. More on that over here: http://www.thegsresources.com/_forum...85#post2182685

I left off with the top case bolts removed, and all the bottom case bolts cracked loose except for the last one. That stripped out. Of course the very last bolt I need to remove to split the cases would be the one to strip... Actually, I'm just grateful it was only 1 bolt that stripped in the entire disassembly... not too big of a deal, I can think of worse nuts or bolts that could have stripped. I'll cut a slot and try my impact driver... If that doesn't work, I'll just drill it, tap it, buy a new bolt and move on.