Rebuild and modifing my 1979 GS 425L... Oh Boy!!!

[Fraphead]

I'm finally getting around to my winter project to keep me sane during the rainy season here in the PNW.

The plan is to rebuild the engine and as well as restore/modify much of the worn and ugly bits on the bike. I bought her last February for $400 after she'd been neglected in the Portland weather. This is going to be a crash course to motorcycle repair for myself, and hopefully get a bad ass personally modified bike for my graduation! I've not had any training at this, but I've done all my own motorcycle work for the past year of riding this bike, and I'm reasonably smart and mechanically minded, and I've got loads of indoor rainy weather. So I'll hopefully be able to pick some of your brains for advice and knowledge over the next few months.

 

[Fraphead]

My first project that I'm working on right now is to strip off the old cover and foam of the seat, and the plan is to re-foam, as well as recover with vinyal. The seat base it metal though, so I'm going to use a rivet gun. Has anyone ever riveted a seat cover down?

I'm also wondering what type of foam works the best for this?

 

[Gorminrider]

I don't think I'd use rivets. I find I have to adjust the cover a few times,to get it taut so even self-tapping screws + washers might be better, at least to get the cover right and then replace with rivets if you insist on rivets.
Wasn't the seat originally hooked on? This is how my 81 400 with a steel seat pan has it... I mean hooked onto points stamped out of the seat pan? These can hopefully be straightened and re-used, especially if you clean the rust off .

BUT, you also can get upholstery "hook strips" or "tack-strips" on ebay or maybe from a local upholsterer if the originals are real bad and this is an easier way .
Another option I haven't tried but occurs to me is to attach some high density plastic strips or something else tha will hold a short staple well and then use a staplegun.Staples hold pretty well and can be pulled out to adjust the cover.. Stainless staples are preferred but painting cheap ones after would help.
There's a fair amount of upholstery help on the web of course.
here's just one I was watching, but note that they are using Stretch Vinyl Fabric. To get a similar stretch, with the usually available marine vinyl, you would need to cut all your material on the "bias" and it takes far more material...
▶ How to Recover a Motorcycle Seat Using Stretch Vinyl Fabric - Using Allsport Vinyl - YouTube

 

[spyug]

Stapling is way easier if you have the media to attach to. As Gormin said , if you can attach high density plastic strips to the metal it should work or as he also said and perhaps even easier, self tapping screws with thin washers to grab the material.

Curious that you start the project with the seat but to each his own I guess.

Good luck with it and be sure to post lots of pics........its going to be a long cold winter I fear.

 

[Gorminrider]

Yes, you have no pix anywhere, Fraphead. Maybe that is your first project!
I'm not exactly sure what kind of foam is original either, It's not awfully exotic and my guess is you can find suitable at most bed-foam shops in the highest density. If the foam-shop does upholstery too, they might help you in more ways.

 

[Fraphead]

HaHa! I've been thinking that I need to start to get into the habit of taking pictures while working on stuff... so here is a few to explain this project.

The original seat was pretty ****ed when I got the motorcycle, and was covered with hot pink ducktape. From what I can tell someone long ago let the foam rot under a cut on the cover, so to fix it they hacked away the rotted bits with a knife (when I say hacked, it was like swinging-with-a-machete bad), and then filled the gap with rags, then taped over the gash in the cover. The foam and cover are both being replaced, and I've got everything but how to attach the cover figured out.

I'm going to try to find some plastic strips as you suggested Gromin. I haven't thought of that and from what I've heard stapling is the way to go. Especially since a bunch of the hooks in the seat pan are about pretty chewed up/rusted out.

 

[Fraphead]

Split crankshaft help!

Split crankshaft help!

I've been plugging along mostly just fine... and I've found I'm much better at searching for answers then asking for them on this site. Since I've not kept this thread very update.

I'm all the way to the point of getting the engine opened up... all the nuts and bolts are removed... triple checked with both the book and visually. I'm pretty sure everything has been removed that has to be before the split. I've gone from tapping it with a rubber mallet, to whacking it, to gently using a pipe as a lever in the clutch plate area... and even carefully tapping a thin blade into the seam at bolt sleeve areas (where no oil goes).

I've still got nothing... and am about to take it into a mechanic to have it done for me... but I'm really trying hard to do all the labor myself and thought I'd pick the brains of some fellow GS riders! Especially those who've got something close to a '79 GS425.

Is there a hidden bolt I'm missing? Should I start playing with heat? Is there a magical type of chemical that eats the seal away? What have you had luck with in the past?

 

[cowboyup3371]

What part of the engine you are at - removing the head or splitting the cases?

 

[tkent02]

Not sure about the 425 engine, but most have a few hidden bolts. Under the oil pan, hidden around a corner filled with grease and grunge, etc. There is also usually something to help split the cases cast into the case itself, either a place to thread a bolt to push the two halves apart, or something. It should be fairly easy if all the bolts are out.
The Suzuki Service Manual is your friend here, do you have one?

 

[Fraphead]

I've got a Clymer Manual. And this split is the horizontal, metal-on-metal seam of the lower end. Unfortunately the 450 has a built in pry-point... but not the 425... sigh...

This shouldn't be something that takes too much effort to split? Once its is ready too split at any rate.

 

[livetheride514]

I'm at the same point as you and CANNOT get the cylinders off the crankcase, no matter what I try. There has to be a hidden bolt or something.