New Airhead Project

Discussion in 'Airheads' started by guywithchickens, Oct 10, 2017.

  1. guywithchickens

    guywithchickens Been here awhile

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    Thinking ahead...do I need to tear into the motor to replace any seals? Recall that this bike only has 11,000 miles. I already have the top end kit from Bob's (http://www.bobsbmw.com/store/product/top-end-reseal-kit-all-r65-models). I'd rather avoid going deeper if possible. I do think I need to pull the transmission off to check/lube the splines, correct?

    Also, internet claims I can replace the pushrod tube seals without pulling the piston out of the cylinder completely. Clearly, I can't replace the cylinder head gaskets this way. Is this critical?
    #61
  2. fxray

    fxray Long timer

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    Your kit will include new head gaskets. You can replace the PRT seals without separating the head from the cylinder if you want to, but I'd say that would only be appropriate in an emergency. I'd go ahead and install the new head gaskets. Removing the head from the cylinder doesn't mean you have to pull the cylinder off the piston, so you can still change your PRT seals without disturbing the pistons and rings. If you want, you can pull the cylinder just far enough to remove a circlip at one end of the wrist pin, then slide the pin partially out. That lets you leave the piston and rings inside the cylinder and still remove the cylinder for ease of cleaning gasket surfaces and replacing O-rings, if present. If you do that, you should have a new circlip on hand to replace the one you removed. It's your choice, but I consider it foolhardy to ever reuse a wrist pin circlip.

    With your low miles engine, I'd take a "wait and see" approach. Up front, there is a seal on the crankshaft and the cam. There is also a seal on the tach drive. At the back, there is the rear main seal and the O-ring under the oil pump cover. All of these would require some special tools and more of your time and effort to access them. There is a good chance they are still O.K. anyway.
    #62
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  3. guywithchickens

    guywithchickens Been here awhile

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    Following fxray's example, I cleaned the final drive with WD-40 and a brass brush. Wiped clean, then a little pewter Rub-n-Buff. Looks pretty good, but it did feel a little like applying makeup. Or at least what I assume applying makeup feels like.

    IMG_1165.JPG
    #63
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  4. Uke

    Uke visualist

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    Lipstick on a cow?
    #64
  5. fxray

    fxray Long timer

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    That looks very nice to me, but the Rub 'n Buff doesn't appeal to everybody. A little rubbing with some mineral spirits takes it back off, but once it is on there, it seems to hold up very well without any repeat applications. The R90/6 that I am working on now seems to be cleaning up to nice, even alloy, with no etched spots like my other one had. I am going to forego the Rub 'n Buff this time around and go for the natural-alloy-survivor look.

    You are doing some nice work on your bike. I'm enjoying your thread.

    Ray
    #65
  6. guywithchickens

    guywithchickens Been here awhile

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    Ray (or anyone else) - what is the correct orientation of this tapered washer/spacer? I assume fatter end toward the bearing in the FD?

    spacer.PNG

    (Thanks to Ray for the photo.)
    #66
  7. fxray

    fxray Long timer

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    ^^^ Yes, guy, I believe I had the pieces laid out in that picture such that, as you pick up the left edge of each piece, it would be oriented correctly to go onto the shaft. Another way to say that is that all the surfaces that are facing upward in the picture will be facing outward (to the right in the picture) when assembled to the drive unit.

    The exception to that would be the heavy washer at the bottom of the picture. I think the counterbore in it is placed toward the soft, waxy washer. It looks like, in the picture that I have the waxy seal side facing upward. Maybe I thought that one was obvious enough that I wouldn't be confused? I've slept since then.
    #67
  8. guywithchickens

    guywithchickens Been here awhile

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    Excellent! Thanks.
    #68
  9. guywithchickens

    guywithchickens Been here awhile

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    I was in the process of putting the nose of the FD back together. Starting to put on the final nut and I noticed a part sitting on the workbench below the wheel the FD is strapped to. It's the spacer/washer that goes behind the oil seal! I have no idea what happened. I either forgot to put it on, or it fell off during FD strapping to the wheel. Had to disassemble and clean off all the gasket maker. Took a night off and started over. All is well now. You can't make some of this stuff up.

    Here's an anecdote from the DR350 days:

    "Hopefully you're smarter than I am...I got my entire motor back together and installed last fall then found 4 "funny shaped" washers on my workbench. They were the valve spring seats. Had to pull the head back apart, then dropped a valve retainer (the tiny bits) down an oil passage, which luckily led to the clutch cavity, not inside the cases. That was a tough 24 hours."

    http://advrider.com/index.php?threads/dr350-thread.230695/page-2288#post-31398813
    #69
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  10. guywithchickens

    guywithchickens Been here awhile

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    Rear swingarm removed and transmission out. Cleaned the swingarm with WD-40 and brass brush. It was really greasy. I plan to do a little prep and masking and hit it with rattle can paint (Dupli-Color DE1635).

    Obviously, I need to clean the outside of the transmission. I got Honda M77 lube for the splines. Do I need to do anything else to it? As far as I know, the tranny works fine. What about the clutch? Again, it seems to work fine, so I don't want to accidentally make things worse.

    Still debating about just pulling the motor for cleaning. I'm pretty close at this point. What's the motor weigh (without transmission)?

    IMG_1175.JPG IMG_1174.JPG
    #70
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  11. lucky6600

    lucky6600 Long timer

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    Great progress!!

    Enjoy reading the refreshment .

    I often ask myself how far do I want to dig into a refreshment on an airhead project. The lesson I learned from those years is if it wasn't broken, don't fix it.
    #71
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  12. fxray

    fxray Long timer

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    For me, it's always an inner struggle between if it isn't broken, don't fix it, and as long as I'm in here anyway, I may as well. I'm dealing with that again right now.

    Guy, what does your Dad think of the project?
    #72
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  13. guywithchickens

    guywithchickens Been here awhile

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    Dad's pretty excited. We rode the bike a lot together when I was a kid (7-10 yrs) and we lived in Wyoming. I spent many hours on the back seat. He's well past riding now, he prefers his old Jeep. He gets lots of pics, although my mom wonders why they're getting pictures of parts. She would prefer pics of grandkids.
    #73
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  14. guywithchickens

    guywithchickens Been here awhile

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    Amen :clap
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  15. DK Dan

    DK Dan Airhead adventure rider

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    I managed to pull the motor (without transmission) out on my R80 G/S. It's heavy but it can be done (and I'm no Arnold Swarzenegger).
    Put a small jack under the motor to hold it while removing the motor bolts.
    And cover the frame with some rags to avoid scratches.
    #75
  16. guywithchickens

    guywithchickens Been here awhile

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    Painted swingarm. Looks pretty good. Before/after below...

    Also, I got the Forney brass brushes delivered. They work much better than a brass brush by hand. They also require much less WD-40. Currently cleaning up the transmission. Only downside is that they say 15,000 RPM max. My Dremel is 35,000 RPM (not variable speed), so I'm using them in my cordless drill. Maybe Santa will bring a variable speed Dremel...

    IMG_1177.JPG IMG_1178.JPG
    #76
  17. guywithchickens

    guywithchickens Been here awhile

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    Had to travel for work this week, so no progress. However, I'm off for the next two weeks, so I've got some time.

    I was thinking during my trip that I may go ahead and strip the frame and get it powder coated. I've already removed the whole rear end, airbox, transmission, etc. The engine will be easier to clean on the bench. The frame has a little rust and a lot of grease/oil. I'm in no rush to ride, since it's winter (and I have a V-Strom). Feels like this is the opportunity.

    A couple questions:

    1. How hard will it be to reinstall all the wiring? I'll take copious photos, but could still be tricky.
    2. How much prep do I need to do prior to bringing to the coater?
    3. Any recommendations on coaters in CT?
    #77
  18. fxray

    fxray Long timer

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    Guy, for what it's worth, I debated the same issue and went with powder coat. Before and during the process of removing the wiring and cables, I wrote myself detailed notes and made sketches, in addition to taking lots of pictures. Using that, I really had no trouble getting it back together. I took some pictures and marked them up for the powder coat guy, to show him where I did not want powder. That worked well. Click here for that. Since that time, I've had that same powder guy do some other work for me, and it always came back quickly and well done. I got to thinking that I was going overboard with trying to protect the parts and telling him how to do his job. When I took my Harley engine parts to him, I left it to him to protect the gasket surfaces etc, though we did talk in detail about what I wanted. He nearly destroyed my engine. I will never do that again.

    As far as prep work, when you find a powder shop, ask them what you need to do to the parts before you drop them off. The guy who did my Triumph said to bring him the stuff dirty and greasy. He ran the parts through an MEK wash, then a regular wash tank, then through an automated shot blast, then did the powder. That was a larger, factory setting where I had a connection until they sold to new management. Those folks removed the powder coat line.

    The guy who did my R90/6 frame and related parts just had me get rid of the worst of the grease and oil. He did the rest.

    The flip side of all this is that I have a friend who has done a number of airheads and other bikes. He has done several bare frame Triumph builds, where he got the frame powder coated, but he has also done a few airheads. On these, he left the engine in the frame and made the bike look like new anyway. He cleans the bike in detail. If there is a section or even a small area of the frame that has rust or is scraped up, he masks around that, preps it, and spray paints it. When he gets done, the bike is perfect.

    I don't think your frame looks rough enough to warrant stripping it down, but that is obviously your decision. I am not going to do that with my current R90/6 project.
    #78
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  19. cycleman2

    cycleman2 Been here awhile

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    On the airhead that I restored combination of R50/5 & R75/6 parts I though about powder coating but like the painting look much better. It looks more natural to me, plus I could do it myself. I did the painting myself and all the prep work on the bike, including rebuilding fenders etc. For the frame just get a 2 part black paint with hardner and you do not need to clear coat the frame. Just use a semi gloss paint. It makes life easier as time goes on and you have to use universal black paint for touchup rock chips etc.

    With respect to the pushrod seals. I would leave the head alone at this stage with that low miles there is no need unless you've got oil leaks at the base. I would replace the base O ring, just because you are going to disturb it when you pull the barrel out of the block. Just pull the head/cylinder out just far enough to let you replace the seals. Make sure you get them oriented right.

    Seeing as you have the engine & tranny split I would pull the clutch and change the rear main seal & the O ring on the oil pump. These parts are cheap and the newer seals are better and seeing as you are in there that far it would be a shame to find out when you got it all together and a couple of 1000 miles later you had a leak. If there are no leaks at the front seals then I would leave them alone as they can be changed later with a minimal amount of work. But then again they are cheap and if you've got the time go for it.

    With that year of bike you are likely going to have to do the valves at some time. BMW had seat issues in some of those years and it was a case of when not if, they had to be rebuilt. With those miles I would run it as is, keep track of the valve adjusts and if they are going out of adjustment more frequently then look at doing the heads. A lot of bikes went a long time before the valves had to be rebuilt. Something to keep in the back of your mind.

    I won't get into how to do any of these procedures, lots of good info on this and other sites on how to do the process. Good luck on your project.
    #79
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  20. bajaburro

    bajaburro Ancient Adventurer

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    All that patina gone forever.
    #80