Norton head building video

Discussion in 'Norton Commando Classic Motorcycles' started by jseng1, Feb 12, 2018.

  1. jseng1

    jseng1

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    Nov 26, 2009
    Here's the new head building video.

     
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  2. Jerry Doe

    Jerry Doe Administrator

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    May 21, 2003
    Great video, thanks
     
  3. hobot

    hobot

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    Oct 19, 2005
    That got me high Jimmy!

    I forgot about valve seats sending Peel other wise bare head for cryo tempering, it squeezed em right out so had more delay/expense replacing. Controversial on non iron alloys but I and others think contracts alu so much/hard its sort of like shot peening inside out.

    Its the very ends of rockers that matter most for inertia and if done enough, completely solve the pushrod puzzling, 1st time every time, that your big OD pushrods may aggravate. Check out Dunstall's rockers to see how conservative almost waste of time/cosmetic only yours are. The only danger of lightening rockers is exposing the very shallow oil passage on side arms, not the ends. Pushrod mass is insignificant compared to rocker ends so alu is better than steel mainly for the shock absorbing elasticity and thermal expansion matching.
    http://i184.photobucket.com/albums/x93/hoboter/RockersDunstalljpg.jpg


    Ever studied up on exhaust valve dia vs flow vs heat exchange limits? Its the main limiting factor in boosted or NOX sprayed Nortons.

    Once the valve train good to 10+ grand the stroke friction sucks down benefit in upper gears, so review the piston surface texturing I acidently discovered with worn down perfect knurling.
     
    Last edited: Feb 12, 2018
  4. robs ss

    robs ss VIP MEMBER

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    Aug 16, 2016
    Very helpful - thanks Jim
     
  5. lcrken

    lcrken VIP MEMBER

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    Mar 15, 2009
    Nice video, Jim. You're getting pretty good at this video production thing.

    Ken
     
  6. Gerard Rowley

    Gerard Rowley

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    Dec 22, 2016
    Jim once again a great informative video and as per always you have no fancy tooling just stuff we can all get hold of. Can’t wait to try out some of your products in my bike.
     
  7. NKN

    NKN

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    Mar 28, 2016
    Precious video, thanks Jim
     
  8. batrider

    batrider

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    Aug 9, 2008
    No thanks on that lapping job. You will have concentric rings on the valve and seat. There are only 4 valves so no need to speed through it with a drill.
     
  9. jseng1

    jseng1

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    Nov 26, 2009
    With a drill - lapping only takes a few seconds. You don't have to get heavy handed with it.
     
  10. oldmikew

    oldmikew

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    Jul 25, 2015
    If rockers are radically lightened there is a serious possibility of breakage. Gus Kuhns a one time well known Norton race team and dealer advised against it.
     
  11. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    Yes - radically rocker lightening can bring breakage and you can usually tell just by looking at the part to determine if its been dangerously weakened. But reasonable lightening (without going to far) helps guard against valve float and dropping a (raced) valve and improves reliability while reducing strain/wear. That's why I give dimensions of the rocker end diameter. As stock the rockers have some crudely made out of round overweight ends on them.

    Same goes for lightweight pistons etc. Reducing weight a safe amount can save your crank and cases from failing. Going too far on the heavyweight or the lightweight side is going to force some expensive adjustments. It all shows up in the testing (usually on the track where you will overrevv the motor to beat that next guy into a turn).
     
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  12. lcrken

    lcrken VIP MEMBER

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    Mar 15, 2009
    Well said, Jim.

    Ken
     
  13. oldmikew

    oldmikew

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    Jul 25, 2015
    Thought yours pukka-I have seen them as thin as paperknives , not installed mind and one wonders how long they last .Something that puzzles me is that no one seems to have tried using titanium for the tappet locknuts, surely its a worthwhile weight saving for those building racing motors ?
     
  14. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    I think that's because the aluminum nuts work well and are even lighter. I've used them a lot, along with the socket head adjuster screws, and never had one fail.

    Ken
     
  15. oldmikew

    oldmikew

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    Jul 25, 2015
    ive got socket head adjuster screws... had unhappy experince with aluminium nuts they came loose ... where do you get yours from?
     
  16. hobot

    hobot

    Joined:
    Oct 19, 2005
    Never heard of a rocker breaking no matter how ground down their ends are, only grinding too much on the side of arm that exposes/nicks rather shallow cast in oil passage to ball ends. Take arm edges to knife sharpeness but dont get too aggressive near middle of arm sides bulge area. Again main reason/advantage is pushrods never foul installing/removing again *IF* taking off most the very ends of the rockers the most. The rest is just cosmetics as very few will test past 11,000 rpm like me so no worries mate'. I forget which side the oil way cast in, IIRC its on the acute angle side to ball end. Would be nice if someone could tell us w/o learning the hard way but end matter way more. Might catch a glimpse before poopbucket ads cover it over.
    http://i184.photobucket.com/albums/x93/hoboter/rockerstop_zpsf7bc10be.jpg

    As significant performance refinements continue, implies no one yet has obtained the ultimate non Norton but know for certain Norton modified parts could endure over 9grand routinely over 4 decades ago engine wise so gearbox and clutch were the limiting factors back then. Newbies may not know the feats of Norton parts to lend perspective on 'advancements'.
     
    Last edited: Feb 14, 2018
  17. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    I bought a batch of them from a company called Alloy-Tech many years ago. They had them for Norton, Triumph, and BSA rockers. The company has been out of business for quite a while now. The nuts were made from 2024-T4 alloy. RGM, and probably other suppliers, still supply them, but I have no experience with any except the Alloy-Tech brand.

    To be fair about it, my experience with them is all from race bikes that didn't get a lot of total miles on them, and also had regular valve clearance checks. It's certainly possible that they might not be as suitable for higher mileage use in street bikes.

    The titanium nut idea sounds good too. The problem would be in finding someone to make them in the proper thread form (9/32-26 Whitworth), and with a suitable anti-seize coating.

    Ken
     
  18. Fast Eddie

    Fast Eddie VIP MEMBER

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    Oct 4, 2013
    I use RGM alloy tappet lock nuts, no problems thus far.
     
  19. oldmikew

    oldmikew

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    Jul 25, 2015
    Thanks very much chaps.. will try RGM . Ken thanks for letting me know about alloy grade used... useful info. The problem with small batches from small firms in the UK is that they sometimes use whats to hand rather than a suitable grade of material.
     
  20. Lineslinger

    Lineslinger VIP MEMBER

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    Feb 26, 2017
    Thank you for posting the video, lots of insight there.
     

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