920 engine build waffle

Discussion in 'Norton Commando Classic Motorcycles' started by Fast Eddie, Oct 31, 2016.

  1. trident sam

    trident sam Well-Known Member

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    Well, you never do things by half !
    Is this motor for another chassis or for the blue Roadster ?
    As usual , it looks fab :mrgreen:
    sam
     
  2. Fast Eddie

    Fast Eddie Well-Known Member VIP MEMBER

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    It going in the Blue Bomber Sam. One day I'd like to put it, or similar, into a nice new build, lightweight Manx rep chassis. But that'll have to wait a bit...!
     
  3. gtsun

    gtsun Well-Known Member VIP MEMBER

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    Well,,, before looking at these pictures I never thought of myself as being a purveyor of porn, but after staring at them I don't know what else you could call such pictures !!!
     
  4. baz

    baz Well-Known Member VIP MEMBER

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    what a great looking/spec motor i'll be following this with great interest,brilliant stuff
     
  5. cjandme

    cjandme Well-Known Member

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    Plus One here! :mrgreen: All I can say is - I gotta make more money.
     
  6. Fast Eddie

    Fast Eddie Well-Known Member VIP MEMBER

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    Not much progress lately guys I'm sorry to report. I did get the pistons from Jim though, a slight variation on his normal design with a thicker crown and 0.040" dish in the crown. If my fag packet (for avoidance of doubt with oir colonial cousins, that's a small cardboard box containing cigarettes) calculations are half right, this dish will give me the desired CR and still allow for a tight squish.

    [​IMG]

    [​IMG]
     
  7. Fast Eddie

    Fast Eddie Well-Known Member VIP MEMBER

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    The 920 motor will be fiddled with over summer and hopefully be ready to nail in the the bike next winter. So I thought I'd fiddle about with the bike in its current form ready for spring.

    I decided to go back to Cafe Racer guise. I got a JPN replica gear pedal from RGM which goes well with their T160 style kick start nicely, I've not ridden with the reverse lever on a Commando before though, so we'll see what its like. Along with the 2:1 exhaust, the neater footrest arrangement certainly cleans up the RHS of the bike:

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    cNw front brake fitted, usual beautiful quality:

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    Mikes 2:1 pipe certainly goes with the Cafe Racer stance:

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    Still some more jobs to do, but we're getting there.
     
  8. Fast Eddie

    Fast Eddie Well-Known Member VIP MEMBER

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    Well, not much progress of late gents, but I have at least managed to get a little shed time.

    As ever, we have a little scope creep here, I decided it would be better to build a separate 'stand alone' bottom end, so have another pair of JS's lovely rods now ready to go in the Maney bottom end.

    The cases will receive a little fettling, just to ensure the nicest fit in the chassis etc and also to clean things up cosmetically, then I'll drill the extra oil hole below the pump, then they're ready for 'tumble cleaning'.

    The barrels will be double checked for clearance with the new pistons, the bores will go for carbide treatment before the barrels will also be ready for tumble cleaning.

    I wouldn't usually have bothered with tumble cleaning, but that's what Comnoz did to the head, so it's kinda raised the bar for the rest of it!

    I'm just in the process of looking at cam / follower fit etc.

    Hopefully the bottom end will be ready to button up in the not too distant...

    [​IMG]

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  9. gripper

    gripper Well-Known Member

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    Jim, can you explain the machining process involved in "waisting" the barrel bolts? I'm guessing it's not just a case of running a lathe tool along them.
     
  10. freefly103

    freefly103 Well-Known Member

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  11. Brooking 850

    Brooking 850 Well-Known Member VIP MEMBER

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    Nigel did you get the email I sent with cam timing pics and data?
    <Mike
     
  12. Fast Eddie

    Fast Eddie Well-Known Member VIP MEMBER

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    Another small step for mankind...

    I received the barrels back from Laystalls who have silicone carbide coated the bores. I've never had this done before so it's all new to me! Its a nice finish, has a kinda dull, off-grey appearance similar to hard anodising on aluminium.

    I have a few weeks away from the workshop coming up now, so hope to get the Pistons sent away for Diamondyze treatment and the cases and alloy barrels sent away for tumble cleaning.

    There should then be very few remaining (viable) excuses in the way of beginning bottom end assembly.

    Onwards and upwards...
     
  13. Fast Eddie

    Fast Eddie Well-Known Member VIP MEMBER

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    IMG_0577.JPG IMG_0578.JPG IMG_0584.JPG IMG_1173.JPG Thought I'd put some pics here that got lost thanks to those b***ards at photo bucket:
     
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  14. Fast Eddie

    Fast Eddie Well-Known Member VIP MEMBER

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    IMG_0095.JPG IMG_0096.JPG IMG_0097.JPG IMG_0098.JPG I got the Maney cases and barrels back from a guy called Stephen Smethurst today (thanks for the lead on him Sam). I did some fettling by hand before sending to Stephen, he does 'tumble cleaning' similar to that Comnoz did on my RH10 head. This gives a really nice smooth sheen finish, it's hard not to think they've been lacquered or something similar. Not only does it look nice, but due to the fact that the process closes the pores in the material, it should make it easy to keep clean in the long term.

    Maney's quality is first class in my opinion, but he makes racing parts, and isn't concerned with appearance. I don't think the photos do them full justice, but they now look SO much nicer!

    Next step is to procure the remaining parts I need for the bottom of the end so that as soon as I've finished faffing around with my Bonnie, I can start assembly with this.
     
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  15. jseng1

    jseng1 Well-Known Member

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    And then you passed pliobond on to me (thank you Ken). The trick with pliobond is to apply it to each surface - the head, both sides of the gasket and the cylinder - many people miss this. Too prevent weeping you have to have a good bond between the sealer and each metal surface. Silicone and soft sealers with little or no adhesion will fail - the oil will just worm its way through. Applying pliobond to just one or two surfaces such as the HG and then clamping it down is not good enough. After the pliobond has bonded to the metal - then you can assemble and the layers of pliobond will bond to itself. I always add the .005" copper wire around the pushrod tunnels and oil return as well - and I never have leaks anymore.
     
  16. fiatfan

    fiatfan Well-Known Member VIP MEMBER

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    That looks fantastic! And it doesn't do any harm to the surfaces that are machined? Is this done in a big barrel with some material tumbling around?
    Tommy
     
  17. Fast Eddie

    Fast Eddie Well-Known Member VIP MEMBER

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    No damage to machined surfaces, slight visual evidence but no more.

    Yes, it's put in a big barrel with ceramic balls, as I understand it.

    I don't know much about it, but I am now a fan !
     
  18. gortnipper

    gortnipper Well-Known Member VIP MEMBER

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    If you use Chrome, this plug in works a treat. I can see all of your old pics on my pc, but not my phone...have to check if there is a mobile version. I understand there are also extensions for Firefox and IE as well.

    https://chrome.google.com/webstore/...nk-fix/kegnjbncdcliihbemealioapbifiaedg?hl=en
     

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