Measuring gearbox end-play

Discussion in 'Airheads' started by DiabloADV, Jun 3, 2012.

  1. ME 109

    ME 109 Long timer

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    Well then, after my recent tranny rebuild using a shim plate, I've more confidence in the solder method.
    What diametre solder did you use?
    If you took just .05mm from your solder thickness, and your input shaft spun freely after assembly, it would suggest that my concerns of the solder distorting the cover (and ultimately giving a tighter clearance than thought) are groundless.
    #21
  2. a_bakla

    a_bakla A&F

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    <DIR><DIR>
    My Rosen core wire was tin and had space at the center. This tin was soo soft that I can even bite and shape it.IMO this type solder wires cant distort the cover.The cover is designed to handle much more force to be able to function.


    </DIR>
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    [​IMG]
    #22
  3. mendoje

    mendoje Been here awhile

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    Can you post the exact brand and part no. of the solder you used? I'm suggesting this so that if we all use it as part of a standard procedure, we can get consistent results.

    Thanks!
    Jeff

    #23
  4. supershaft

    supershaft because I can

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    As I have said a while back, any solder I have around is soft enough. I just thought that I would be concerned with the solder being too soft as far as measuring your clearance with the oil baffles on the bearings. The solder might not be hard enough push them down all the way. Oh well, loose doesn't hurt a thing as far as I can tell. Too loose does from what I can tell. Like I said earlier, I think they shift slightly better set up as tight as possible but, then again, I shift my airheads way more often than anyone I have ever ridden with.

    I set up all my tranny work including my own setups without the paper gasket. I have never had a problem for it and I do think it is easier to nail the clearance if that is what you want to do. I use Durko there. Actually, I think they hold oil better without the gasket myself.
    #24
  5. 2VEZR25

    2VEZR25 Recuerde el 911

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    For those with transmission experience: As a guide and after all calculations; What would be the typical measurement range of shims (min/max) before being alerted that either a calculation or something internal is not right?
    Thanks.
    #25
  6. ME 109

    ME 109 Long timer

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    For me, it was .85 - .95mm
    #26
  7. Bigrider

    Bigrider Living the Legend

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    I have taken apart two five speed trannies. After the first one I was given some advice to measure the clearances of the tranny with original shims right after taken off the cover before removing anything. This will give you a ballpark figure for what the whole system should measure once you get everything back together, generlally within a few thousands. Any gross difference may indicate the pieces weren't seated fully. Another tip was to place new shims on a flat piece of 800-1000 grit sandpaper and lightly snad to take off any burrs that may throw off the measurements even by a little bit.
    Dave H
    San Antonio, TX
    #27
  8. supershaft

    supershaft because I can

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    IMO, I wouldn't use what was in there as a guide. A lot of them I have worked on were set up more than a couple of thou on the loose side. Tons of them were shipped that way. They work fine that way but I do think they work better set up tighter. I think that loose end play has something to do with some bearings walking on later snap ringless trannies while others don't but that is really another story. That and I put them back together without the gasket. I know quite a few that do that. Easier to nail the shimming and they tend to leak less without the gasket IMO.
    #28
  9. Moto Phoenix

    Moto Phoenix Adventurer

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    I have recently uploaded a series of videos on my YouTube channel on rebuilding airhead gearboxes:


    https://www.youtube.com/channel/UCvdotfJvcTWbr9Tj5rAWTCA/videos?view_as=public

    In my opinion there are two problems with squashing solder to find the clearance. First, although solder is very malleable, it is a relatively hard material (in engineering terms) and it also has some elasticity. BMW state the clearance should be either 1/10th of a mm or 1/500th of a mm. Given the aforementioned properties of solder, and the required clearance I am not sure if it would give the desired accuracy. Plastigauge may be an option, but in either case I would need to see convincing evidence before using it. However, the factory method also requires much patience and practice to get consistent and accurate results.
    #29
  10. Darryl's bmw

    Darryl's bmw Darby

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    Are you using a transmission shimming plate

    To keep the shafts parallel when you are doing the measurements.

    There is a BMW tool for that, very expensive.

    I have seen one made out of an old rear cover that was cut down to .200"
    #30
  11. Moto Phoenix

    Moto Phoenix Adventurer

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    Yes I have all the tools. Have a look at my videos by clicking on the link and you can see how it is done
    #31
  12. 100RT

    100RT Long timer

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    Did it look like mine?
    [​IMG]
    #32
  13. disston

    disston ShadeTreeExpert

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    Plainshorse,

    Thanks for posting your videos. Unlike some of the other choices we have had in tutorial videos your's look watchable.

    Almost forgot, Welcome to the Asylum. We are the inmates. Now you are one too.
    #33
  14. Darryl's bmw

    Darryl's bmw Darby

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    A bit thinner, only .200" thick same idea.
    #34
  15. nothing

    nothing Been here awhile

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    Why not use Plastiguage instead of solder? One is made for such use, one is not.
    #35
  16. ME 109

    ME 109 Long timer

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    Plastigauge doesn't like heat. Heating the cover to install it, will destroy plastiguage. That is why moldaguage is used, but what a pita to use.

    Solder will work with repeatable results, when a process is perfected. I like a shim plate.
    #36
  17. Bill Harris

    Bill Harris Confirmed Curmudgeon

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  18. disston

    disston ShadeTreeExpert

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    I have a couple of bad rear covers. I will give one of them to somebody that will do the milling work. I'm thinking that somebody who can do this themselves? But maybe somebody will have to have it done? Then return one of the covers to me.

    Anybody interested PM me. I will not repeat this offer anytime soon. I will post back here if it gets worked out.

    EDIT; The covers are spoken for. Thank you.
    #38
  19. Stan_R80/7

    Stan_R80/7 Beastly Gnarly

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    Thanks for sharing your videos!

    I especially appreciate the description of oil flow through the output shaft. I was wondering about that. I've got a used 1984 gearbox disassembled with pristine gears and virtually no wear. My working gearbox is a 1978 (that has different helical gears from the 1984) and based on the few bits of metal chunks on the magnetic plug when the oil is changed, is not pristine. But, I'm sure it has no broken gear teeth.

    One of my goals is to compare using Kuster 44 63/37 lead-tin solder 0.031" diameter as a measurement technique with a shim plate. My shim plate is from Cycleworks and the measurements are all depth, much like you showed with the cover. This is a hobby for me so doing silly redundant measurements is not a problem. I also may swap gear sets between the two gearboxes - which will require replacing the clutch assembly.

    Also, I've been removing the gears and bearings with a sturdy three jaw puller and an impact wrench then reseating them with a length of brass pipe and a hammer. I'll see if this approach stops me from doing any work, but at this point I'm (hopefully) not looking to remove and replace any gears. Just remove bearings and reshim. Again, I enjoyed your videos!
    #39
  20. Moto Phoenix

    Moto Phoenix Adventurer

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    Thanks for the welcome and the kind comments.

    I quite enjoy making the videos in between bouts of travel, it's likely I'll post more up from time to time. So keep an eye open.
    #40