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A1 running at last

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A1 running at last Empty A1 running at last

Post by rich07961 Sat May 09 2015, 14:29

A1 running at last Imag0636


Well I have been stumped and have had loads of problems trying to get her to run, seats have been cut, valves ground in, new rings and all was looking good magneto good spark, checked all timing marks, set timing as per you tube video, checked points opening at 20 degrees before TDC new gaskets, cleaned out carb again, all I was getting were spits and pops through carb and exhaust all day yesterday
( arm got very tired by now)
got a bit frustrated as checked and double checked everything, so took magneto apart and cleaned last night, put back on this morning still nothing but pops and spits, then I remember someone on here
held the throttle link in the closed position and no choke to start, thought try anything once, now to my joy 2 swings and away she went such a relief, only thing is this is the only way it starts and ticks over good but does not like having revs increased, have tried mixture setting but no joy either way, but at least it runs thats all I need at the moment, now I can get on and restore her hopefully to her formal glory.
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Post by tony RA Sat May 09 2015, 22:28

I have one as well that was good running when I got it .but has stood in the workshop for the last 10 years must drag it out of corner and give it a swing .but I know they van play hell with your arm
All the Best with yours

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Post by Nixie Sun May 10 2015, 19:38

just a word of advise. you should never run an air cooler engine without the fan cowl fitted.

Bob

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Post by Darryl Ovens Mon May 11 2015, 03:31

Very short runs with no load are Ok provided you keep an eye on its temperature.  When it starts to warm up shut it down.
The "only starting with a closed throttle" comment may have been mine, I've had several do that.  
A likely cause is a spark plug breaking down under pressure, (or possibly shorting somewhere else in the ignition).  Closing the throttle limits the quantity of air that can be drawn into the cylinder.  This results in lower compression once the engine gets a little speed on.  Air resistance to the spark increases quite considerably as the air pressure increases.
Consequently the voltage required to punch through the air increases proportionally.  In many case this voltage becomes sufficient to jump through usually the plug insulator, resulting in no spark in the cylinder.  Spark and plug looks Ok when you try it on the side of the engine because that is only at atmospheric pressure.  So 1st thing is try a new plug or a known "good" plug, (I've even had new plugs breakdown under pressure, so if needed try more than one).  If it still does this then you are looking for an arc gap somewhere else in the ignition secondary circuit, (ie hi tension side), that is too small.  Or maybe dirt on an insulator somewhere that is allowing the spark to "track" over it.  Can be a hard thing to find.
Commercial spark plug testers had a means of testing the plug under pressure.   Also notice how much longer the plug insulator is outside the cylinder compared to the business end inside the cylinder, pressure is lower outside.

Cheers
Darryl

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Post by rich07961 Mon May 11 2015, 22:17

Hi thanks for comments, my main objective was to get it running so I can get on with restoration, see my other post ref new project and you will probably understand why I did not want to go head first into doing paintwork and things before I knew it would run, when it finally ran I stopped and started it a few times just to see if mixture was ok and other things, not had it running since, as for spark plug I must admit I had tried a few different ones all with same result in starting, the ht lead needs changing and will get a better plug for it as recommended,also when I took manifold off and the head they were pretty black from running to rich so whether this has anything to do with starting am not sure, I am unable to remove the mixture screw seat to clean so probably that could be the problem of not being able to get mixture right. I have noticed tonight when cleaning the dynamo that the ht lead is loose on the connection to coil this I can sort when I get new lead.

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