Author Topic: 1914 HUMBERETTE "Cyclecar" Valve Timing  (Read 3740 times)

Offline iansoady

  • Advanced Member
  • ***
  • Posts: 688
  • Karma: +6/-1
    • View Profile
    • Email
Re: 1914 HUMBERETTE "Cyclecar" Valve Timing
« Reply #15 on: October 20, 2021, 11:06:15 AM »
I wonder whether the "oil control" rings were partly to blame? I always err on the generous side for rebores with older engines - an extra couple of thou over standard will have no appreciable effect on compression etc but gives that margin of safety. Norton suggested that my 79mm bore ES2 would need a rebore when .007" or so oversize so plenty to play with. And who wants to spend the rest of their lives running in?
Ian
1952 Norton ES2
1986 Honda XBR500

Offline cardan

  • Advanced Member
  • ***
  • Posts: 1035
  • Karma: +18/-5
    • View Profile
    • earlymotor.com
    • Email
Re: 1914 HUMBERETTE "Cyclecar" Valve Timing
« Reply #16 on: October 20, 2021, 10:11:44 PM »
Hi Ian,

Probably partly. I don't use oil rings in early (veteran) bikes, on the advice of the people who taught me about this stuff. There's also a riding/driving tip for old engines that goes with having no oil ring - make sure to roll off the throttle every now and then to draw some oil into the top of the engine to get at least a whiff of oil for the bore and the exhaust valve guide. And an eggcup of oil in the petrol for the inlet guide.

The price is scraping the crusty-oily crap off the top of the pistons every 20 years or so.

Oh, and keep the oil going in, and don't run lean, and don't over-advance the ignition, and don't over-rev the engine, and... it's not easy to keep a really old machine running nicely, and (fingers crossed) stop it from going bang. And that's assuming it has been rebuilt correctly - at least we have Radco to help us with that part of the game!

Cheers

Leon

Offline john.k

  • Advanced Member
  • ***
  • Posts: 509
  • Karma: +4/-0
    • View Profile
    • Email
Re: 1914 HUMBERETTE "Cyclecar" Valve Timing
« Reply #17 on: October 22, 2021, 01:46:24 AM »
Water cooled engine...was there any water..........I do know someone who bought a Scott for much dollars,and ran it without water.....for a little while.