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Project A festering thought of building an 8 cylinder 500

Discussion in 'Other Projects - Other Bikes (non 250's)' started by Gen, May 6, 2021.

  1. Gen

    Gen Well-Known Member

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    At LAST,,,I have a crankshaft that spins freely after the crankcases are torqued down to the recommended torque :party:
    It took me over a week, 11 crankcase splits & 4 sheets of 400, 4 sheets of 800 wet'n'dry, a "special" aluminium tube, one end fitted snugly in a bare crank journal, the other machined down to allow for the wet'n'dry's thickness, which was used to fine tune the journal after bearing blue was applied, a few twists at a time, one journal at a time.
    One of the main problems was caused by mismatched top & bottom crankcase 1/2's due to the 1st engine's upper case having a hen pecked cylinder liner, that, unfortunately, could not be removed, requiring another crankcase to be cut in half (the 1st set was a trial run anyway, just to "see" if it was possible)
    The case upper / lower , and crank journal codes were were worked out, as per the norm, but the crank seemed a "bit" too tight, even after the bench test spin (3 x 3 minute spins @ 60 rpm)
    #3 set of shells were pink, the thinnest available, so the crankcase journals had to be enlarged , a few microns at a time, until they were "right"
    Once #3 was free, #1, 2 # 5 needed the same treatment, but not as much,,,
    I might take up repairing Ladies wrist watches next, they are a lot bigger inside, with larger tolerances,,,

    I still haven't found the source of the metal shavings that were in the sump,(unless I had uncontrolled crank end float due to no CDI trigger wheel, or alternator rotor being fitted during the bench test0 , or maybe I stuffed up washing the dark internal corners of the cases ?
    The oil pump screen stopped most of the swarf, as the pump was squeaky clean inside :)
    Tiny
     
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  2. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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  3. thebeefsalad

    thebeefsalad Well-Known Member

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    Wild that you had to add clearance for the thinnest shells. Were you using plastigate or measuring to determine clearances?
     
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  4. Gen

    Gen Well-Known Member

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    Plastigage sux with the minute specs these bikes use, either that, or whenever I buy it, it's been living under a shelf in the shop so long, it's turned into a rock and won't squish easily,,,
    How, when Honda line bore their crankcases, the specs can vary (A B A B A for example), you would think, if they are machined, a smaller diameter journal could not be followed by a larger, then small, repeat ? for example ?
     
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  5. gregt

    gregt Well-Known Member Premium Member

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    Depends I suppose on how much coolant is being pumped during machining. We've all had alloy build up on a cutting tip machining dry. Also the temperature of the cases when machined will affect the finished sizes. Even how they're mounted - one or more main could be adjacent to a cold hunk of machinery acting as a heat sink - or the reverse putting heat in.

    What you did reminds me of repairing FZR1000/R1 heads which have had the cam caps put back wrong and seized the cams.
    Patient scraping and a hand held "align hone" tool.
     
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  6. Mike Green

    Mike Green Well-Known Member Premium Member

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    After fitting mismatched crankcase halves together and finding the crank wouldn't turn I'm not surprised. The clearances are tiny and cases are obviously machined bolted together.
     
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  7. Gen

    Gen Well-Known Member

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    [​IMG]

    [​IMG]

    [​IMG]
     
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  8. Gen

    Gen Well-Known Member

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  9. Gen

    Gen Well-Known Member

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    Machinist once referred to a person with skill, a master at their chosen craft, a person who is passionate, flexible & proud of their work, someone who enjoys the challenge of creating something difficult.
    I'm searching for that person :superman:
    I am NOT searching for someone who makes a good curry, demands payment be made by Western Union
    I Have found a dim sim creator , but they do not understand what a M8 x 1.25 tapped hole is, nor can they open a .STEP file, but insist they are masters of all CNC related whirly , grindy cutty machinery :headbang:
    Today might be the day I mortgage my Mum
    [​IMG]
    [​IMG]
    [​IMG]
     
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  10. jmw76

    jmw76 Well-Known Member

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    Gen, I gather you need to create the bevel drive from motor to gearbox. Now a silly question, but you exhausted all avenues for potential donor parts from car/garden tractor diffs???

    Keep up the good work.

    Peter.
     
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  11. Gen

    Gen Well-Known Member

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    The hardness of finished off the shelf pinion shafts would make putting a taper, keyway & "puller" thread in the guts damn near impossible without compromising it's strength Peter
    Arfa pinion.jpg

    "Plan B" gearbox orientation
    [​IMG]
     
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    Last edited: Feb 7, 2022
  12. Gen

    Gen Well-Known Member

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    Maybe, just maybe, :confused: s-l1600.jpg
     
  13. garry55

    garry55 Well-Known Member

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    Great work there matey :thumb_ups:

    my unfinished V8 800cc from back in the day............

    [​IMG]
     
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  14. Gen

    Gen Well-Known Member

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    I bet you got a stream of "it's not a "real" V8 comments Garry, I'm carefull not to refer to this project as a Vee anything, rather "conjoined fours"
    Did you ever get to fire it up ?
     
  15. jmw76

    jmw76 Well-Known Member

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    What are you talking about? I see 8 cylinders and they are in a V arrangement. The fact that there are 2 cranks makes no difference. There were a few V4 bikes in the past with 2 cranks. Tell whining purists to get over it.
     
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  16. garry55

    garry55 Well-Known Member

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    You are correct - not a "true" V4, unless you draw an imaginary line through each cylinder block to a point where a single crank would be. Closer to being a square 8 than anything else.
    A messy divorce put paid to this (and several other) projects so no, it never ran in anger.

    Timing side.................

    [​IMG]

    and on the day it was collected by its new owner.....

    [​IMG]
    and yes, I do know the front forks are fitted the wrong way round.

    no idea what happened to it after this.
     
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    Last edited: Mar 5, 2022
  17. garry55

    garry55 Well-Known Member

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    I think that the term "V" as applied to engine design has always been abused - Ducati's are referred to as V- twins even though the factory use the "L twin" designation. Suzuki's ill-fated TL1000S and TL1000R are another example - according to Suzuki the design brief was for a Twin cylindered engine in an L configuration, hence "TL". Then they adorned the bike with "V Twin Super Sport" decals.......
     
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  18. Gen

    Gen Well-Known Member

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    More progress, mostly in my head, but,,,heading in the right direction :D
    [​IMG]
     
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  19. Gen

    Gen Well-Known Member

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    One step closer to having a connected gearbox,,
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
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  20. Gen

    Gen Well-Known Member

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    Playing Spotto

    [​IMG]
     
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