R80G/S Rejuvination

Discussion in 'Airheads' started by 4puf, Feb 26, 2012.

  1. 4puf

    4puf Adventurer

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    The other day I've got myself a nice R80G/S

    [​IMG]

    My plan is to take it apart, fix it, paint it and make it mine.

    I have owned a GS in the past but I never did any major work other than oil and spark plugs. This time though looks like I will have to go all the way :D

    As soon as I got it I went for a ride. the engine rides well, a little rough at idle but I am overall surprised how well it rides for a 1985 bike.

    When I got home I parked it in the garage and started the dismantling process. This is what it looked like by 7PM :evil

    [​IMG]

    Question 1: I want to have the frame powder coated and therefore I need to completely remove the engine. How much of the engine I have to dismantle to be able to remove it from the frame?

    Question 2: Since the engine runs fine I am tempted not to remove piston/cylinders gearbox etc. What do you guys think? Should I just go ahead and open it up to see how everything looks inside or is just better to leave it alone?

    I'll have more questions later on but that would do for now.

    BTW. I've got myself the shop manual from this site http://www.carlsalter.com/bmw-service-manuals.asp That's cool!
    #1
  2. hardwaregrrl

    hardwaregrrl ignore list

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    Gotta take the trans off to pull the motor.
    #2
  3. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    I'd drop the oil pan, check it out for sludge and clean it. This will tell you how often he oil has been changed. Clean the oil pickup strainer and check pickup bolts for being tight. Go ahead and remove the tranny and grease the input shaft splines.

    It might be easier to remove the tranny while the engine is in the frame. Remove engine bits that you want to get powder coated black. Motor will come out fine w/ the tranny removed, no need to pull apart further.

    How many miles are on it?? If a lot you should have done a compression test before you pulled it apart. Oh well. Don't go into the motor until you get it back on the road. If compression is low or valves need work then it's easy to do.


    Check my G/S link below for some good reading. Also Infracycle has a good writeup.

    BTW- to reove the headset race, run a bead around the race w/ a MIG welder and it'll drop right out.
    #3
  4. bgoodsoil

    bgoodsoil Dare to be Stupid

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    Pull back the driveshaft boot at the back of the geabox and use a 12-point 10mm, in the stock tool kit, to remove the driveshaft bolts. Use the rear brake to keep it from rotating on you.

    Remove the swingarm pins. They'll use a 27mm socket and a 8mm allens. Some 27mm sockets are too wide around the outside and will need to be trimmed, but a normal craftsman seems to work. Remove the brake rod nut then pull the swingarm back and out.

    Remove the exhaust nuts and take the headers off. After time, those nuts can get stuck. DON'T use a big set of channel locks to remove it. You'll need a special exhaust nut wrench to get it off. If they're stuck, and really stuck, you may need to cut those nuts off rather than risk trashing the threads on your head. The thread repair is faaaar more expensive than new exhaust nuts. When you put the nuts back on during the rebuild, put some anti-sieze on those threads. Many people recommend spinning them off and reapplying anti-seize every year.

    Using 2 10mm wrenches, undo the bolt that holds the clutch on onto the back of the gearbox . Slide the arm out being careful to keep the bearing from sliding out. Now remove the hoseclamp that holds on the boot. Use a magnet to pull out the cup, thrust washer and clutch rod. The rod will come out right through where the swingarm was. Having this rod removed will make pulling the gearbox a whole lot easier

    put a jack under the back of the oil pan. Remove the rear engine mount stud and crank up on the oil pan enough to lift the back of the engine a bit. This will help get the gearbox out. Undo the 4 bolts holding the gearbox on, disconnect the neutral switch wires (carefullly!) and pull the gearbox out. Be mindful of the neutral switch and make sure you don't smack it on the frame on the way out.

    Undo all the wires going to the engine, remove the front engine stud, and lift the engine out. You can do it alone even with the jugs on. I'd remove the starter though--it'll make it a lot lighter. I'd put the alternator cover back on for this to make sure you don't hit your bean can or alternator.

    I wouldn't take apart the top end if everything's working fine. It's not any harder to do it on the bike later versus on the bench while you've got it out.
    #4
  5. Infracaninophile

    Infracaninophile Finding My Way..

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    Once you have the exhaust, trans, and swingarm off, the engine can just be lifted out of the frame cradle carefully by twisting to the left. I have an old thread here somewhere where I took my 81 G/S all the way down to the component parts. I'd remove the carbs from the engine along with the airbox and everything else will come right out.

    Just FYI: IF your headers are horked up they are NLA (No Longer Available) from BMW. Meaning your options are limited to Keihan or a few of the other aftermarket companies.

    BUT... There is an ad on the IBMWR right now in airhead Parts where someone has a brand new set of G/S header pipes for $400 brand new in the shipping papers. Personally I think the stainless Keihan's are a good value and the headers from there are not too expensive. The BMW ones are steel (pretty sure).

    Keep up the good thread.

    Tom
    #5
  6. 4puf

    4puf Adventurer

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    Guys, thanks for the detailed explanations. I don't think i would have been able to do it without messing something up.

    Now I have the gearbox out with the engine is still in the frame because I still don't have the exhaust wrench. Should be getting it soon.

    [​IMG]

    Everything went well except that I made a cut in the clutch boot while moving the gearbox around. :-(

    Next I will have to get all the frame pieces ready for powder coating.
    I will also have to find a good body shop that can completely remove the old paint from the tank, fix a couple of dents and repaint it. Actually i think the current paint is standard spray paint that can probably come off with some paint remover.I'll give it a try tomorrow.
    #6
  7. Infracaninophile

    Infracaninophile Finding My Way..

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    4:

    After looking at your last picture it might be time to remove the front wheel and forks and then let the whole thing sit on the ground. You can get some cheap saw horses and a piece of 3/4 - 1" rough plywood and make a nice work surface off the floor. The engine, sans carbs weighs 125 pounds.

    Tom
    #7
  8. bgoodsoil

    bgoodsoil Dare to be Stupid

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    It looks like you still have the emissions system installed. It's a pipe that runs from your airbox, under the cylinder to the a small port underneath each header. I've heard folks say it makes the exhaust valve run hotter and it's better to remove it. You plug the airbox with plastic plugs from the hardware store and the port at the cylinder has a metal nut to cover it up.
    #8
  9. 4puf

    4puf Adventurer

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    I am waiting to get the exhaust wrench before I go any further just in case I have to re-bolt the engine to the frame to give it a little more lever when is time to remove those finned bolts.
    BTW they look newer than the rest of the engine so my guess is that the PO had to saw the original off
    [​IMG]
    maybe that will make the removing process a little easier.
    #9
  10. 4puf

    4puf Adventurer

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    You are correct, the emission system is still there. Do you really think I should remove it? Will it have any impact on the way the engine will run? and how do I plug the hole under the cylinder?
    #10
  11. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    whe you put the exhaust nuts back one don't forget the anti seize.
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  12. kantuckid

    kantuckid Long timer

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    Don't discount the notion of cleaning up the frame & shooting it with base coat & clear. Powder coating is just another way of applying paint using heat vs. solvent. If you want proof of my argument(beside the fact that any painter can shoot it with solvent) just take a look at the vast number of aftermarket parts examples of failed powder coating that was applied under very controlled conditions. I've owned lots of PU trucks & most had steps, hitches & other stuff, powder coated black & it peeled off in chunks after a few years. It is not a cure all finish! My contention is to say that, like is true for any paint job, the prep is what matters most.
    Like he said, you should have done the compression:wink:
    #12
  13. bgoodsoil

    bgoodsoil Dare to be Stupid

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    #13
  14. 4puf

    4puf Adventurer

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    That was an interesting page. good information just repeated over and over and over.... :-)
    Well, I will go ahead and plug these holes. The fitting coming out of the head was not stuck at all. I could almost unscrew it by hand.
    I will also remove the hose going into the carburetors and plug the vacuum port.

    The good thing of all this is that it will clear all that clutter inside the bottom part of the air filter :D
    #14
  15. 4puf

    4puf Adventurer

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    Good point I will make sure they do a good job. The shop told me they sand blast everything and make sure everything is nice and clean before they get started with powder coating. I'll also ask them if they have any warranty on their job... not that I believe much in that but at least should make them be a little more careful.
    #15
  16. 4puf

    4puf Adventurer

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    My project is currently on hold until I get the exhaust wrench so I started thinking about getting ready for the rebuilding process. Here are a bunch of things I still have to figure out.

    Air filter and brake pads - should I go with the original or buy aftermarket?

    Fluids - same question about original or aftermarket. here is the list
    engine oil
    gear oil
    transmission oil
    fork oil
    I'll also need a new fuel line. What is the size that would fit correctly?
    Spark plugs?

    I'd like to order everything online unless someone has a parts store to suggest around Philly.
    #16
  17. 4puf

    4puf Adventurer

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    I forgot...
    How do I clean the outside of the engine? and I am not talking about just a power wash. I would like to get rid of all the stains that are so common of this engine. Is sandblasting too much?
    I tried doing some baking soda blasting using my compressor but the result was barely noticeable. I have to say though that it might have been due to my compressor being one of those super-cheap one
    #17
  18. Beemerguru

    Beemerguru Beemerguru...G/S guy

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    NEVER sand blast an engine or tranny unless you have it completely apart so you can clean out all the grit that gets into every single oil passage! Soda blasting works great but you have to have about 180psi at the nozzle for effect.

    You're in for a lot of fun...lots of areas for improvement with the G/S..or leave it stock and have a blast.

    The drive shaft boot was probably old anyway and bolts are single use. The airhead is stone age technology..can be fixed anywhere with the standard tool kit.

    Give me a call if you want to talk G/Ss

    Greg

    1.415.205.7829
    #18
  19. kantuckid

    kantuckid Long timer

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    Have you ever seen a powder coated Ferrari?
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  20. One Less Harley

    One Less Harley OH.THAT'S GONNA HURT

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    I bet some of their parts are powder coated.....
    #20