In which Plaka builds a Cafe bike.

Discussion in 'Airheads' started by Plaka, Oct 30, 2018.

  1. ME 109

    ME 109 Long timer Supporter

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    You'll be disappointed by the headlight bucket, there's nothing in there.
    spokester likes this.
  2. Plaka

    Plaka Brevis illi vita est

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    so it's full of nothingness? Most very zen gwasshoppah.



    that will make it easy to switch buckets to keep the tip-o-lite controls.
  3. ME 109

    ME 109 Long timer Supporter

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    This is Jim Gregory's pic of his mono RS bucket. Pathetic really, compared to my '81




    [​IMG]
    Bigger Al and ccmickelson like this.
  4. Plaka

    Plaka Brevis illi vita est

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    Got out the pressure washer and some other tools. Time to get he grunge off. It's gonna snow tomorrow.

    grunge hammer.jpg

    Then drained the oil. Not a magnetic plug. Bad. Also had truly big chunks in the oil film on it. Under the scope the chunks resolved into clumps of fine brown fiber. Looking at the oil filter should be interesting. The PO was running cheapo asian Emgo filters ( and was kind enough to include several in the sale).

    The scope is a 70x B&L I got for cheap at an industrial auction along with a machinist stand. Priceless, if bulky.
  5. Jim K in PA

    Jim K in PA Long timer

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    Nice sledge!
  6. Plaka

    Plaka Brevis illi vita est

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    Got into the left side. The mysteries deepen, a lot! I expected deposits on the exhaust side of a worn head from valve stem blow by. This head has them on the intake side also. The backside of the intake valve has as much carbon on it as the chamber side and that looks normal. Very light deposits in the intake tract of the head. No drippy oil in the carb tubes. Carbs show black streaking, they have been sucking piston blow by. Emissions removed. Supposedly a K&N air filter (did I say the guy was cheap?). The PO was running .004 intake clearance but I didn't check it befoe pulling the head. Piston skirts polished hiny with blow by streaking around the pins. Nickasil a bit worn---you can see the piston sweep area as more smooth. So what gives? Seems that intake valve is open during combustion, at which point the thing should barely run, yet it idled, fast and slow, fine. Spark plug looked fine.

    l-head-outside.jpg

    Valve lips actually looked pretty good. Proud of the seats all the way around. Photoshop enhanced image.

    l-head-valves.jpg

    Ex. lifter has a tiny pit dead center. I'll pick the best of he 8. I want to know at this point if the crank and cam are good. If so I'll run this bottom end.

    l-ex-lifter.jpg
  7. cantupshift

    cantupshift Been here awhile

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    Can we see pictures of the piston?

    Asking for a friend.
  8. Plaka

    Plaka Brevis illi vita est

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    couldn't get the piston pin circlip off. Will try again tomorrow maybe.

    Did get the air filter out. Is indeed a K&N, vastly over oiled and weighs a ton. Doubt it's breathing. So the intake tuning is indeed srewed. My theory on the intake valve at this point is lack of scavenging during overlp due to intake tract obstruction with exhaust gasses blowing back onto the open intake valve.
  9. Piggdekk

    Piggdekk love speed, hate rush

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    If You get combustion residues in the intake tract then the valve is not sealing. Did you check how it seals?
  10. Plaka

    Plaka Brevis illi vita est

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    Good point. no, I didn't. Given the wear I doubt the valve is concentric in the seat as it sits. They're junk. Good cores if someone has a damaged one but useless otherwise. But the bike came with a complete set of valve springs new in a sealed factory bag.
  11. Plaka

    Plaka Brevis illi vita est

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    Well somebody wanted piston pics. Two things of interest, Best I can measure there is no measurable wear on them. The moire pattern in the photos shows that the machining marks go to the bottom of the shirts. However there are some light scratches going top to bottom on the thrust faces. Bad oil filtering.

    piston edge.jpg
    piston scratches.jpg


    But the rings are pretty gone. One big end bearing is cherry;. The other is scored deeply into the shell. But good to save on those cheap filters.


    scored big ebd shell.jpg
  12. Plaka

    Plaka Brevis illi vita est

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    It was so cold in the shop today it took a heat gun to get the pan drain plug back in. But I got some things done anyway, narcotics be blessed. Went in to look at the oil filter, expecting it to be crushed. Nope. But what's wrong with these pictures? (hint, it isn't in the oil that came out either)

    black o-ring.jpg

    black o-ring filter.jpg

    Compression on the white o-ring is minimal but existent. Canister depth is 3.26, 3.60, 3.80. No shims.
  13. PaulRS

    PaulRS Dutch fool

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    O-ring missing.

    Paul.
  14. ME 109

    ME 109 Long timer Supporter

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    Unfiltered oil at worst, which could be worse than you expected.
    You gonna pull the crank out? Do you know how hard it is to get someone to pull their crank 'round here?!
    Cogswell likes this.
  15. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    How's the check ball?
  16. Disston

    Disston ShadeTreeExpert

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    Is the little black o-ring on the filter missing?

    Is this what Paul is seeing Too?
  17. Disston

    Disston ShadeTreeExpert

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    Is the little black o-ring on the filter missing?

    Is this what Paul is seeing Too?
    boxerboy81 likes this.
  18. PaulRS

    PaulRS Dutch fool

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    I don't see double. :lol3

    But there should be an O-ring in the cover, middle ring, see where the wear mark is on the filter itself.
    Not the small seal on the tube, that is not used in this case.

    Paul.
  19. ME 109

    ME 109 Long timer Supporter

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    Further to the rocker shaft discussion, here are the two types. Earlier model with the drilled and plugged oilway. rocker shafts.JPG
  20. Plaka

    Plaka Brevis illi vita est

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    looks intact.