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1980 GS850GLT - Getting her back up to riding condition

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    #31
    Last Big Update: It's complete!

    Okay folks, so I had a week off of work before I started a new job, so I spent most of that time--you guessed it--working on the bike!

    I'm very happy to say that my GS850 is up and running again, license plates renewed, and I've put about 120 miles on her since getting her going again. I'll try to summarize everything I did and for a few things that I think might be helpful, I'll post new threads for further discussion.

    1. Completely re-wired the entire motorcycle, replaced the wiring harness, fuse box, and all connectors, and added several upgrades (I will post a new thread on this with more details)
    2. Rebuilt the forks, using the guide from the bikecliff site. I used sonic springs, and aftermarket seals and dust covers from z1 enterprises, and new fork oil from z1 (make sure to get 2 bottles!)
    3. Rebuilt both front calipers and the rear caliper with aftermarket rubber parts. (so much brown sludge under the pistons!). Replaced back pads with orange EBC semi-sintered (front pads still on order).
    4. Rebuilt both the front and back master cylinders with OEM rebuild kits (each came with new piston and seals) (again, more sludge)
    5. Replaced all brake lines with Earl's brake lines and fittings (I read about this on the Earl's thread)
    6. Back to the engine, put new piston rings on, added OEM base gasket (liberally smeared with Hylomar Blue), gently slid cylinder block down on pistons (used fingers and plastic trim tool to compress rings)
    7. Replaced head on block with OEM MLS head gasket (thinly smeared with Hylomar Blue)
    8. Replaced camshafts (used assembly lube in the journals)
    9. Checked tappet shim clearances and adjusted shims to be in tolerances again (strangely, most were a bit loose. I would have expected them to be tighter from valve lapping, not looser)
    10. From here, I used a home-built rig to test compression on the bench. I'll post a new thread on this as well to show how I did this. Compression was around 150 PSI for all 4 cylinders! Success!
    11. Since I had ordered more REAL Gaskets and got them in, I replaced the oil pan gasket and stator cover gasket. I tried replacing the clutch gasket, but the REAL Gasket I got for that wasn't right.
    12. I replaced the clutch springs with 3 OEM, and three EBC after market (+15%) springs.
    13. I put the valve cover back on (I reused the REAL Gasket for this from 7 years ago, still in great condition!)
    14. I reinserted the engine back into the frame (using my engine crane and holding the engine with a pull-strap looped twice around the block/jugs)
    15. Re-mounted engine, engine guards, exhaust, pegs, brake pedal, kickstand, etc.
    16. Re-mounted carbs and airbox, connected throttle, clutch, fuel line.
    17. Fired her up! I didn't even need any starter fluid, just a twist of the throttle. Then adjusted the idle.
    18. Balanced carb idle screws. (Hung up temporary fuel tank (a cut-out 80w oil bottle) and carb balancer (motion pro fluid manometer) and ran a fan in front of the bike)
    19. Used a colortune on each cylinder to adjust idle a bit more.
    20. Rebuilt (standard, not vacuum) fuel petcock as it was crudded up a bit and not flowing freely.
    21. Reinstalled tank and added inline paper fuel filter since the tank has a bit of rust in it.
    22. #2 still showing a bit cooler on the exhaust header than the others, so I got her out to ride a bit and break her in a bit and run at higher throttle.
    23. Re-added my Garmin Zumo 350 and mount (and wireless tire pressure gauges)
    24. After riding over the weekend, I followed the BikeCliff instructions on using EvapoRust on the tank. I let it sit for 4 days, and still had a bit of residual rust leftover, unfortunately.
    25. I fixed the fuel sending unit as it was broken in two places (I'll post a new thread on this with pictures on how I did it)
    26. Replaced the broken tachometer cable, used motion pro lube and tool to lube both tach and speedo cables
    27. Re-added the tank with a new petcock (old one was leaking just a little), new paper filter, got the air bubbles out of the fuel line

    Notes about the above:

    - For the fork rebuild, I wasn't able to use air pressure to pop the seals loose. I had to use a sharp awl and hammer it into the middle of the old seal and pry it out that way.

    - The caliper pistons were very stubborn to get out. I had success with an air compressor set to about 80-100 PSI and a rubber-tipped air nozzle pressed hard into the banjo thread hole (don't forget to tighten up the bleeder bolt first!) And I was careful to face the piston down onto the table because man, do they fly when they finally pop out!

    - For the front master cylinder, the circlip was really difficult to remove because it's deep in there. Even the right-angle long snap ring pliers wouldn't work. I ended up using a pair of forceps as makeshift snap-ring pliers and that worked better than anything else.

    - For the brake system in general, I really recommend rebuilding the entire brake system all at once for any bike that hasn't been regularly serviced in this way. There was so much sludge in every part of the system that rebuilding part of it would just have distributed the sludge around the new parts.

    - For the head gasket, I originally had included the rectangular o-ring around the cam chain, but when I tightened the head down, the o-ring popped out into the cam chain area in a few places. I loosened up the head and removed the o-ring and was more liberal with the Hylomar Blue in that area to make up for it. Hopefully loosening and tightening the head on the head gasket doesn't result in any leaks.

    - Using an engine crane for taking the engine in/out is a bit of overkill, but it's really nice to have it well supported while positioning it in the frame.

    - I forgot to mount the kickstand before the exhaust, so I had to loosen the exhaust mounting enough to wiggle in the kickstand mounting bolts. Not fun. I should have mounted the kickstand first.

    - A heat gun on the carb boots works wonders for getting the carbs back on. Much easier!

    - After my motion pro fluid carb balancer had sat for 5+ years, a lot of the fluid had dried up and it didn't work right. Good thing I purchased a refill kit when I bought it. It took about an hour to go through the refill process.

    So after all of that, she's definitely back up to riding condition. I've had her up over 70 MPH so far with no major issues. And I still owe you all 3 more posts (custom wiring harness, bench starter circuit, fuel sending unit fix)

    IMG_1460.jpg
    Last edited by Guest; 10-02-2020, 02:12 PM.

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      #32
      Wow. Well done. That’s a ton of work. If you’re interested in how to post more and better pictures on the forum, I’m sure we’d all be interested in seeing them. I have written instructions on how to use Imgur to do this, linked in my signature.
      Rich
      1982 GS 750TZ
      2015 Triumph Tiger 1200

      BikeCliff's / Charging System Sorted / Posting Pics
      Destroy-Rebuild 750T/ Destroy-Rebuild part deux

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