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Zero valve clearance ?!

Discussion in 'The Garage' started by Uncle Ernie, Mar 2, 2009.

  1. Uncle Ernie

    Uncle Ernie Long timer

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    Royal Enfield says to set the valves with NO clearance. They say as long as the valve lifters turn (spin) without any up & down play, you're good to go.

    This goes against everything I know. It's a set-up not entiorely different from a BMW single. They say the valves loosen up as the engine gets hot. I'm really want to put a guage between the rocker end and the valve. I'm twitching.

    Am I nuts?
    #1
  2. JohnTM

    JohnTM Who's my daddy? Supporter

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    Nuts? Well, maybe...:lol3

    But it isn't impossible that they use zero clearance. Vincents do too.
    #2
  3. VonHelm

    VonHelm corona ring

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    #3
  4. JPSpen

    JPSpen At Large

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    Keeping up with the Joneses, OK ?
    Take a ride, check the valves while it's still hot...
    Then you'll know...............wait for it................


    The Rest of the Story..

    RIP PH

    John
    #4
  5. AzB

    AzB Fattest thin man

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    Do they have hydraulic lifters?

    Az
    #5
  6. Mista Vern

    Mista Vern Knows All - Tells Some.

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    Older HDs ran zero clearance also. You can go to Old School and ask, as a number of folks have REs there.
    #6
  7. Uncle Ernie

    Uncle Ernie Long timer

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    I guess this old dog needs to learn a new trick.
    As described, the procedure seems so amorphous- like throwing the rocker up against the side of a barn. If it bounces once, you're good to go. I spent a long time learning just the right tug on a feeler guage on my Beemers.
    I'll do it- but it's scary.
    #7
  8. GreaseMonkey

    GreaseMonkey Preshrunk & Cottony

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    It really depends on the physical design of the engine. Since everything heats up and expands differently the clearance can change by getting bigger, smaller, or possibly be designed that it all expands at the same rate. Just depends on how the engineers planned it.
    #8
  9. Uncle Ernie

    Uncle Ernie Long timer

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    I think these engines are made by using lava flows for molds. This process hasn't changed in millions of years.

    3 nuts in there to screw with. Damn- what do they do...? BMW's are so easy.
    #9
  10. Mista Vern

    Mista Vern Knows All - Tells Some.

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    :lol3 Now I gotta get one of these just to see what the hell you are talking about!
    #10
  11. Mista Vern

    Mista Vern Knows All - Tells Some.

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    Good stuff GJ - keep the cool info coming!
    #11
  12. Anorak

    Anorak Woolf Barnato Supporter

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    Do what, now? The Vincent has a two guides for each valve which reduces the side load and guide wear. The rocker arm is in between the guides.
    [​IMG]
    #12
  13. JohnTM

    JohnTM Who's my daddy? Supporter

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    As for the construction, you're both saying the same thing.

    The purpose of the design is to place the spring above the rocker. There is still only one guide (ET41 in the parts list) but the shorter effective length of the valve does provide for less expansion effect from heating. Keeping the pushrod short by having the cam high up in the timing case combined with the short valve stem and the angle the pushrod sits at in relation to the barrel makes everything expand at approximately the same rate. Thus, zero-clearance adjustments.

    [​IMG]
    #13
  14. JohnTM

    JohnTM Who's my daddy? Supporter

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    I still don't see the second valve guide. :scratch

    And the higher RPMs are handled by the optional third spring on the valve to help eliminate float.
    #14
  15. JohnTM

    JohnTM Who's my daddy? Supporter

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    If you'll bother to read my earlier post about the short pushrods and the angle they sit at in relation to the barrel, you'll see that I don't think it was pointless - much the reverse - it is an ingenious design.

    But as for the two guides, I'll trust my own experience and the parts diagram over the opinion of a magazine writer any day. You're quoting bad info. What the writer is referring to as the top guide is actually the lower spring keeper which does act somewhat as a guide, but no more so than in any other engine.
    #15
  16. JohnTM

    JohnTM Who's my daddy? Supporter

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    At the last Vincent rally we held in North Carolina, a gentelman arrived toting a big binder filled with all sorts of Vincent memorabilia, fact sheets, magazine articles, and even sung "Vincent Black Lightning". Although he had never owned or ridden a Vincent, he was an expert! Or so he seemed to think...
    #16
  17. bwallca

    bwallca Been here awhile

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    Back to the original question. Some old British singles had zero valve clearance, Matchless/AJS for sure. These engines have a lot in common with the RE, designed shortly after they invented dirt. On the plus side you no longer need a feeler gauge, just do it.
    Ben
    #17
  18. Anorak

    Anorak Woolf Barnato Supporter

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    I knew that would drag you in. I got the explanation from a story Kevin Cameron did about Vance and Hines Prostock Harley engine. He compared it to The Vincent in that they both used high mounted cams to minimize the length of the push rods. Anyhow beyond that I will definitely defer to your expertise. Wanna sell me a Vincent. I'll trade you an autographed Arai helmet worn by Don Angel in Max Lambkey's streamliner at 212.98 mph.
    #18
  19. JohnTM

    JohnTM Who's my daddy? Supporter

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    Sadly I'm down to two Vinnies in the shed right now. :cry Can't spare one. :lol3
    #19