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Author Topic: 1913 Valve timing ?  (Read 3791 times)

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Offline phil_h

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1913 Valve timing ?
« on: 07 Sep 2009 at 23:10 »
Well, I've bodged up the inlet manifold for now, but its not running at all properly, almost as if the timing was out.
I've checked the marks are all aligned, but dont have any technical paperwork whatsoever as yet.
The valve timing seems to be set up with changeover occurring at tdc (and no overlap).
Can someone please advise the easiest way to check the valve and ignition timing please.

thanks
phil
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Offline Chris

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Re: 1913 Valve timing ?
« Reply #1 on: 08 Sep 2009 at 08:49 »
Hi Phil
   Valve timing should not be a problem providing someone has not deleted and repositioned the marks on the crankshaft gear and cam wheel gear. The actual setting with a standard 5b cam is that the inlet opens 5 degrees before top dead centre and closes 30 degrees after bottom dead centre. The exhaust opens 55 degrees before bottom dead centre and closes 10 degrees after top dead centre.
    Ignition timing is easily set as follows:- Turn flywheel in normal direction of rotation until the exhaust valve of the rear cylinder has just closed. Set the advance and retard lever in the midway position. With magneto gear removed, turn magneto until contact points just start to open. Engage the magneto gear with the idler gear and tighten in this position. The engine is now timed to give the spark at the correct time for the front cylinder and will also be correct for the rear cylinder. To ensure that timing is not 180 degrees out ensure that the contact that is opening is the one that provides the spark to the front cylinder. If in doubt remove the front pick-up and ensure that the brass contact on the slip ring is to the front.    Chris.
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Offline phil_h

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Re: 1913 Valve timing ?
« Reply #2 on: 08 Sep 2009 at 14:56 »
Thanks Chris
I think my comment re 'no overlap' should really have said 'no appreciable overlap', as I think the valve timing is pretty much what you have described.
It also sounds nice and easy to pop the points cover and front pickup off to check the ignition timing.
My instinct is telling me that it is 180 out, but I'd rather know the correct drill to set it up before I start looking further.

regards
phil
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