First build.

[Chopperbri]

Good afternoon I hope the quarantine finds you well. I've started my 1980 XS650 build. Motor was out already, frame chopped/ hardtail. I decided to start at the brakes. Calipers looks ok but pistons were shot. Gonna pull the forks blast them too. Got rebuild kits for both already. Looking forward to this thing.

 

[Jim]

Welcome to the madhouse! We love build threads here... and there ain't no such thing as too many pics. We love pics.

 

[YamadudeXS650C]

Good afternoon I hope the quarantine finds you well. I've started my 1980 XS650 build. Motor was out already, frame chopped/ hardtail. I decided to start at the brakes. Calipers looks ok but pistons were shot. Gonna pull the forks blast them too. Got rebuild kits for both already. Looking forward to this thing.

Actually your pistons might actually be usable, if they weren't leaking fluid previously. They don't look too bad.

 

[Mailman]

Welcome to the forum and good luck with your build. Lots of good info here!

 

[Chopperbri]

Actually your pistons might actually be usable, if they weren't leaking fluid previously. They don't look too bad.

The fwd one was leaking. Rubber was all bloated, and looks like someone use channel locks on it preciously. The rear has a big ring of rust that's pitted. I bought 2 new pistons and rebuilds. Better that way.

 

[Chopperbri]

Pulled the front wheel and triple trees. Got new neck bearings and races from all balls racing. Bushings were squishy too. Will shave the legs tomorrow and blast and paint the calipers and trees.

 

[Chopperbri]

Cleaned up the calipers, forks, trees Saturday. Took the forks apart and the seals looked good. I had a difficult time finding pics of exactly what I was getting into with the fork disassembly. So I took pics. Remember this is a 1980 XS650 SG. Forks didn't have enough fluid in them to make a cocktail. First pic is of the stack-up in the lower side of the fork. The outer bottom 8MM (head size) bolt goes through fork, then the taper spindle (silver part at the top of the pic), and threads in the cylinder (bottom part dark grey).
Next pic is of the seal I found in the fork. I had bought new seals with the intent to change them, but they looked fresh and clean. So I decided to save my seals for the winter when I powdercoat the legs.
Last big pic is what the upper side of the compression cylinder looks like. It's 12 point 17mm, the reason why some people weld a 12pt. nut to a bolt to remove. I had a buddy with hex sockets I borrowed.
Thumbnail is of my parts masked and ready to prime

 

[Chopperbri]

Painted parts yesterday and it was a bit cool so they're still tacky. That sent me to the carbs for teardown and inspect. The motor came with pods and non stock pipes, so I'd imagine I need to re-jet these anyway.
https://thexscafedotcom.files.wordpress.com/2014/06/mikuni_bs-cv_carburetor_rebuild_tutorial.pdf Thanks to this page for the photo tutorial I'm able to pull it apart and generally identify all the little pieces. I'm a picture book kinda guy and never done this before. Looks like I need a few throttle shaft seals, and pilot jet plugs (since there were none). Everything else looked pretty sanitary on this side. I'll get to the other one probably tomorrow.

 

[5twins]

You appear to be missing the washer under the main jet. You need that. Combined with the main jet, that's what holds the needle jet in the carb body. Get genuine butterfly shaft seals, not the knock-offs from Mike's. They're cheaper and, of course, better. Best deal is to use the Suzuki part, same seal as the Yamaha one only cheaper .....

https://www.partzilla.com/product/suzuki/13651-51010

Don't put the plugs back over the mix screws, leave them "open" for future adjustments and tinkering. If the screw heads on the mix screws got damaged by drilling too deep when removing the original plugs, replacement assemblies are available and reasonably priced too .....

https://www.partzilla.com/product/yamaha/12R-14105-00-00

 

[Chopperbri]

You appear to be missing the washer under the main jet. You need that. Combined with the main jet, that's what holds the needle jet in the carb body. Get genuine butterfly shaft seals, not the knock-offs from Mike's. They're cheaper and, of course, better. Best deal is to use the Suzuki part, same seal as the Yamaha one only cheaper .....

https://www.partzilla.com/product/suzuki/13651-51010

Don't put the plugs back over the mix screws, leave them "open" for future adjustments and tinkering. If the screw heads on the mix screws got damaged by drilling too deep when removing the original plugs, replacement assemblies are available and reasonably priced too .....

https://www.partzilla.com/product/yamaha/12R-14105-00-00

Man that parts illustration is majorly confusing. The numbers don't match what is listed. I'll have to do some major reading about what's what. I took a ton of pics while taking everything apart. Each piece that came out I took a photo of it and how it came out. I got a gasket kit from Mikes already. Thanks for the tip .

 

[Jim]

That shiny ring is a washer. Under it is an o-ring that's probably squished.