Author Topic: 1914 HUMBERETTE "Cyclecar" Valve Timing  (Read 1918 times)

Offline iansoady

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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
2008 Yamaha X-Max 250

Offline cardan

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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

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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.