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Commando engine into Dommi ?

Discussion in 'Norton Commando Motorcycles (Classic)' started by Chris, Jan 10, 2019.

  1. Chris

    Chris VIP MEMBER

    Joined:
    Jan 21, 2008
    Hi
    I have a Dommie race bike. It's slow, tuning is expensive & once done they are not nice to ride.
    My question it's a small frame & the head is very close to the frame. Anyone have any idea if I can swap the Dommie for a Commando engine (size) also mounting points are they similar?

    Thanks Chris
     
  2. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    It has been done look up the “Other Norton Motorcycles” forum, engine from Commando will have to be canted forward thought.
     
  3. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    Yes you can fit one obviously it'll need to be re balanced without the isolastics fitted
    I don't think it's a problem running the commando engine upright
    But others on here will know for sure
     
  4. marinatlas

    marinatlas

    Joined:
    Nov 4, 2007
    Hi Chris , yes you can (must) do it, I have one cdo engine into a slimline , just bear in mind that wideline have only one pair of front mounting lugs , slimline got two pairs , dunno if it is imprtant or not ( I am the frog friend of Danno ......)
     
  5. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Featherbed frame Chris?

    If so I can’t see a problem, upright or angled.

    Angled would allow you to still use a Maney pipe though...
     
  6. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    If you are racing the bike, you might have eligibility issues. With my bike, in Australian historic racing, there is a cut-off date at 1972 for the most suitable class. My motor is 1973. If I don't win races, I would never have a problem. But the potential for a stupid dispute is always there.
     
  7. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    Which Dommie engine?
    I've ridden a stock 600 (99) and it was painfully slow.
    The 650ss on the other hand is a sharp bike, that engine really goes.
    Had a bit of Herb Becker porting on my SS, that helps.
    I think the main difference tho is Doug Hele's engine design work.
    He made those Dommies fly. His great design ideas used with the Dommie downdraught head were used again with the Commando engine.

    Glen
     
    Last edited: Jan 10, 2019
  8. laurentdom

    laurentdom

    Joined:
    Nov 30, 2012
    Salut Chris,

    Yes you can do it (as shown in my avatar).

    The main rule I was advised to follow is to locate the engine "as low and as forward as possible", which I did. You may/will have to rework a bit the exhaust pipes, center stand etc... and some other details.

    Re: the vibrations, my crankshaft is not re-balanced. I use Jim Schmidt's conrods and pistons instead, and the result is very positive, at least at cruising rpms (up to 5000) from my own experience.

    If you want to have the engine tilted forward, you won't be able to re-use Dommie engine plates. Maybe some vendors can provide you with that.

    Laurent
     
  9. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Chris is racing Glen. Alas, I don’t think there’s a class in which a 650SS would be competitive.
     
  10. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
  11. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    It was a 650ss bike that set and held the lap record at Westwood for years.
    This was against tuned 750 Commando and Atlas bikes.
    The 650 belonged to Dave Matheson.
    One of the 750s Dave beat belonged to John Mcdougall. John had qualified and run at Daytona with the same bike(132mph lap).
    So 650s can be made to run hard.
    Glen
     
  12. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Not disputing any of that Glen... but you don’t see them scoring many points in modern classic racing against Rob North triples, 750 Weslakes, or properly tuned 750 Norton’s...
     
  13. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Are Unity still trading?

    I know that Andy Molnar does them off the shelf.
     
  14. Chris

    Chris VIP MEMBER

    Joined:
    Jan 21, 2008
    Hi
    Bernard thanks, wanted to ask the question, just to get a yes or no, before I started playing. Plenty of material to read.
    Baz thanks for that heads up. I have the main parts of an engine & the crank has been rebalanced.
    Hi Marinatlas I remember you. I have a choice between Croix or Cadwell in June. I agree no choice really I am too big for an untuned 500. Its lovely to ride but more of a country lanes bike. It lurches off the line but is just soft. John ran through everything I would need to do to get it to perform. It made for a very difficult bike to ride all revs just not pleasant.
    Hi Eddie the engine tilts forward in this frame (it's a Dresda!) Far to small for you lol. One of Dave's Daytona frames. The tilt means the head is very close to the frame, fins may need trimming.
    Hi Acotrel eligibility should not be a problem. Dresda frames raced with mainly Triumph engines but Dave had probably wrapped tubes around everything. Years ago the British Historic Racing Club would not let me put a 5 speed Triumph box in it, which it sorely needed 6 would have been better.
    Hi Glen you are right & that is where this is coming from. Many years ago in Classic Bike or Classic Racer Mr Sewell built a 500 Dommie for someone. I still carry a picture of it in my head, a stunning bike. They ran it in the island & all the comments I made earlier were said. It was then converted to a 750 using the Dommie cases. This was allowed under BHR rules as the engine exterior looked the same. I think Doug Jones raced a 650 taken out to 750 he was a lovely man & a great rider & that bike was quick. I like torque & drive, I can rev the nuts off anything but British bikes? My big Commando is a delight I really want to ride a big bore triple in the dry. 1000cc no weight of the crank :)
    Hi Laurent nice looking bike. I have the chance one day to maybe do this on someone else's roadbike. Have you more photos?
    Hi Knut I cut up a set of rear Converta plates to fit the engine & gearbox as the Dresda frame is shorter.

    500 engine, Dresda frame. I have 1/2 a 750 Commando engine & a very old twin disc front end. Enough bits to get some enthusiasm up what's not to like.
    Thanks for your advice.
    Photo below.
    All the best Chris DresdaFrame1.jpg
     
  15. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Oh, I see Chris, not a FB!

    Actually, it was a 500 Dresda Daytona frame that I used for the 900 Nourish (after this geezer relieved me of my Daytona engine!) but you’re not wrong, it was a tad small for me!

    It’s gonna be a squeeze in that frame, but, if you run a short primary belt (as I believe Norman White prefers) you might just do it.

    BTW, I’m pretty sure those diagonal tubes from the headstock, and those from the top tube to the swinging arm pivot area, aren’t stock Degens.

    You’ll just have to get some bits out and start mocking up.

    But shouldn’t you get your Goodwood ride sorted first ?!
     
  16. Chris

    Chris VIP MEMBER

    Joined:
    Jan 21, 2008
    Hi Nige
    The 500 Daytona engine:) is lovely. I did not know your big Triumph 8 valve was in a 500 Dresda Daytona frame! I thought it had to be a bigger frame, cos the Tritons look physically bigger?
    I got the frame because Dave was incensed with the headstock bracing! He also could not understand altering it to fit a Norton engine, so he would not say he built it & the guy could not get eligibility!
    Primary all works well. If the Commando sits in the same place as the Dommie.
    Goodwood project is going better than expected. Bearings traced. Date arranged for the frame fairing & lockstock brackets to be brazed. Not sure about mounts for a shark fin yet! Also not a requirement when it was last raced. Just started cleaning alloy lol
    Chris
     
  17. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Russel is now pretty much the man at Dresda, you could do a lot worse than take a bare engine and cases, and the frame down to see him, he’s a dab hand at fabrication / engine plates and the like. He’d also be best placed to help when it comes to bodywork etc.
     
  18. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    So it's a 500 Dommie at present?


    Glen
     
  19. Chris

    Chris VIP MEMBER

    Joined:
    Jan 21, 2008
    Hi Glenn
    yes it is 500cc. Handles well but everything blasts past on the straight.
    I rode a fully tuned bike special crank steel rods high compression pistons megacycle cam & a 6 speed box. It took me back to my 2 stroke days. Lol the money invested in that engine! A good little one costs as much to build as a good big one.
    Just not my type of ride.
    Chris
     
  20. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    Chris, you may have just saved me a pile of money.
    I've been lusting for a 500ss (roadbike) for ages now.
    I have a hunch that after riding torquier bikes ( Commando 850, Vin 1000) and MUCH torquier bikes( 1360 Vin, 1200 Thruxton)
    the little 500ss would feel a bit sad.
    Similar to my first time riding a Triumph Bonneville 650 a couple of years ago.
    A hotrodded one at that.
    The main sensation was " Is that really it?":)
    We do get spoiled with power today, even worse if you sample something modern and big.

    Glen