[singleminded]

The general  feeling on other forums that i use is that modern fuels need less advance than the fuel available when the bikes were new..Maybe only a degree or two.
A little experimentation MAY be needed to get the best from an individual bike..And believe me TOO much over advance can be disastrous.

[wessex_man]

On the conventional period mags I normally leave the advance leaver fully open when running and only retard when starting or going up a steep hill you can feel the improvement. Generally don't leave it too retarded or your engine will run hot and you will blue your pipes.

I invested in one of the new BTH mags about tens years ago when my period mag packed up (even after a rewind or two). Those first Lucas combined mag dynamos, from bitter experience, are often a source of problems as they loose their magnetism as we don't use the bikes daily any more. Anyway the BTH has an automatic advance built in I've found my bikes easier to start, have noticed an improved performance and fuel economy.


Once you have the timing and ignition right you can start to adjust the carb for slow tick over and better results. Remember modern fuels are different than what the engine was designed to run on so a bit of tweaking is required.   

[singleminded]

Once you get used to riding the bike you will find what suits the maximum advance setting..
My 9A is set to the recommended timing setting with mag set at full advance. I'ts always run nicely at that setting but with a little experimenting I found that once it was warm a little less advance was better ie:- I was cruising nicely at 55mph with full advance and on a long straight opened the throttle and got 60 mph, retarding SLIGHLTY increase the speed to 65mph. I'm certain I could have got 70mph but why kill the old girl she is 84.
On steepish hills then the engine again needs a little retardation. Usually if you feel that it is running out of puff retard slightly and you often feel the power come back in, you certainly feel it on a thumper like my 600 ohv 9A..John

[iansoady]

Quite possible - the air slide should be opened fully (ie pulling the cable as tight as it will go) once the engine will accept it without missing a beat. Again, varies with the bike but I've never had one that needed anything other than fully open after a couple of hundred yards.

The Amal airslide is a pretty poor design as it affects airflow different amounts at different throttle openings. If you have it halfway up it does nothing till about 1/2 throttle then has a progressively greater effect as the throttle is opened.

It also sounds as though you may be running over-retarded (assuming of course you timed the ignition in the fully advanced position). If you look at the way that centrifugal advance mechanisms work, most are on full advance by about 2,500 rpm or even less.

[Andy Cubin]

Brilliant Ian,

Now I have just taken it around the block a couple of times and kept the levers lined up with the grips.

2 times, she faded and died and would not restart.  I suspect flooding caused by me not opening the air lever during riding causing the engine to run over-rich.  Am I correct or is there something I am missing?

Cheers

Andy

[iansoady]

The air lever is only used for cold starting (usually combined with a certain amount of flooding via the tickler). But each bike is different and you need to learn yours's own idiosyncracies.

Ignition lever is normally retarded about 1/3 for starting then left fully advanced most of the time. However, if you're as reluctant as I am to try a downchange approaching a roundabout etc you can retard it which will let the engine pull a higher gear at lower revs. You can hear retarded ignition as it has a flat sound compared to full advance and of course won't rev so freely. The original long lever on the LH bar is good as you can nudge it round with your knuckle.

Hot start is normally with air open and no flooding but 1/3 retarded as above. But sometimes the petrol in the carb can vaporise (used to happen to my old Norton 16H) and it needed flooding to make it work.

One mistake many people make for both cold & hot starts is either to twitch the throttle of to have it too far open. Barely cracked is right UNLESS the engine has been flooded in which case turn the petrol off and try a few kicks with the throttle wide open. It's easiest to keep the front brake on which helps in keeping a fixed throttle opening.

[Andy Cubin]

Evening all from a reasonably sunny Wiltshire...

My Model 8 is back together and starting.
Tick over sorted and now its time to venture out on the road.

The ignition and air levers are new to me and, although I understand what they do, I need some advice on practical riding v lever positions and, more importantly, the consequences of incorrect technique i.e running rich, flooding, etc.

Also - any advice on Hot Start techniques.

Hope the sun is shining where you are...

Best

Andy