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Top end woes

Discussion in 'Norton Commando Motorcycles (Classic)' started by Mwood7800, Feb 17, 2019.

  1. Mwood7800


    Jul 26, 2017
    ok so I put the head back on, adjusting the valves I noticed it seemed hard to turn over but it would turn. While adjusting valves I noticed the pushrod on the left intake wasn’t in the cup but on the outside edge. I pushed the valve down and got it seated. Ran the bike and ran great but lost power at around 4K. Could have been gas or electrical but I took it back apart. Can’t find anything wrong, no bent pushrod or valve, no sign the valve touched anything. Scratching my head as to why it was hard to turn over. Any one have any ideas? Not a scratch on piston or valve. Thanks in advance
  2. concours

    concours VIP MEMBER

    Dec 29, 2011
    Do a compression test, report back.
  3. YukoNorton


    Sep 4, 2017
    Sounds like you have the head off now...how does it turn over without the head on? Did you peer down to see if there was any foreign thing on top of the followers? What was done with the head?
  4. Mwood7800


    Jul 26, 2017
    New top end, turns over fine, not a scratch anywhere, I’m thinking the motor was hard to turn over because it was pushing the intake further down when the rocker was misaligned. Idled fine.
  5. Fast Eddie

    Fast Eddie VIP MEMBER

    Oct 4, 2013
    Sounds feasible, you may have been getting to the point of the spring becoming coil bound, or the top spring retainer pushing hard against the valve seal.

    Was it hard to turn over as in being constantly hard? Or was it intermittently hard? If it was valve spring related it would be intermittently hard,easy, hard,easy, etc.
  6. Steves


    Oct 16, 2016
    When you refit the head (next time) use rubber bands to pull on the adjuster ends of the rockers to keep the push rod end in place. If one pops out and you have torqued up the head it can be a bugger to get back in.

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