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1972 Fastback Combat Going Good

Discussion in 'Norton Commando Motorcycles (Classic)' started by Burgs, May 4, 2014.

  1. Burgs

    Burgs VIP MEMBER

    Dec 14, 2013
    Hi rx7171
    The oil leaks started after the revs rose once I got more miles on the engine (I couldn't help it), keep the revs down and no oil leaks?
    Seems to be similar to the different information available on the internet and various forums.
    We paid a lot of attention to the bores and pistons on the engine rebuild, so by pass is next to nothing at low revs at the moment, bit hard to test on the run :shock: .

    I want to keep the bike looking as standard as possible so will set a valve up in the original breather housing that bolts to the crankcase, this should not be a problem as I have the gear to do it i,e, manual lathe, CNC Lathe and a 5 axis Machining centre, plus other bibs and bobs for my pleasure.

    I have had to ride my ZZR1100 to work this week and what a difference, it goes like stink, stops like all get out, but for pleasure and ease of handling etc the Norton out ways it by a mile :D

    Best Regards
  2. john robert bould

    john robert bould

    Sep 26, 2009
    ZZR 1100 i recon they where to high...followed my mate on mine..we exchanged for a run out, the first thing i noticed how high in the seat he was! but great power lump 147 raw boned horse's!
  3. kerinorton


    Feb 12, 2013
    before my pistons blew I had oil coming out every seem. now it only comes out where I haven't been [ crank case halves ].
    Hey Hobot, I was told an 850 could do 350,000 miles before it needed re-boring. Without good air filters [ which std pre mk III's didn't have, ] you are likely to wear out quicker. I think I have hit a nerve here
    [ referring to air filters because of their crap design]. I modified my air filters on both bikes when I rebuilt them. I still don't think they are perfect, but definitely better.
  4. hobot


    Oct 19, 2005
    Ugh, I had Trixie Combat oil tight till grit got sucked through the booties so put in new rings which solved smoking and spittle out the copper head gasket and stayed clean -UNLESS I gave 'it' hi throttle to get to hwy speed OR if I eased on throttle to get to 70 mph, then above 70 leakes out the engine cases above and below. A power wash in town before its seen at gathering stops, it stays clean for all the how pretty comments from strangers but oils up again on way home. Only thing I know to do is what I'm doing now missing out on best spring conditions, take down to crank and reseal with Hylomar and organic fiber thread, which Wes talked me out of when I had the chance a few year ago d/t rod bolt corrosion fracture. So I learned my lesion again, short cuts on my Commandos usually end up with more work. At some point of combustion pressure and/or rpm our engines become elastic so would take active case evacuation to keep oil in if seam seals have failed. I will try a new questionable flamering from AN I've left on wall aftger 1st one blew out in 15 miles on timid commute and carry spare copper one and tools for a time just in case, not to be stuck waiting on another rescue.
  5. Burgs

    Burgs VIP MEMBER

    Dec 14, 2013
    That's what is happening all good and then too many revs and he becomes elastic, and oil comes out, but before stripping down will try breather as I have 12 others to keep going and also restore.

    Also she who must be obeyed :wink: is also keeping track of what I am up to and not up to, on various fronts, if not obeyed it could become very costly.
    Best Regards

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