Hi
What could be the other reasons of poor starting when hot apart magneto. Mag is freshly rebuilt and worked well last summer. Plug, contacts, high-tension wire? Seems to be electrical problem. I have tried all with the carb - floating and not floating, air valve closed and open. Nothing really helps. Sometimes starting well sometimes not, especially when there is audience with high expectations.

Kalle

email (option): kalle.tikas@gmail.com

It could be petrol evaporation, you should try giving the carb a little tickle. Do you have an insulator fitted between the barrel and the carb?

email (option): davmax@ntlworld.com

Don't retard it so much. The more retard the lesser spark.Try full advance.

Hi, thanks.
25mm insulator is fitted.
Yes I have noticed that it starts better when fully advanced.
I will try replace plug also.

email (option): kalle.tikas@gmail.com

Hi kale,

I would also try to give the points a quick clean,
Just by running a clothe between them when they are closed.
It takes 20 seconds and nothing to lose..

Sometimes, and more often after servicing the magneto,
some grease from the timing adjusting cam ring or the points actuator / push rod cab pollute the points,
and that can have an effect on starting.

Happened to me, anyway…


Noam.

email (option): noam10@gmail.com

Hi

I am still learning to start my M20. Can report that what I feared was a poor mag seems not to be. What I find is:

1) Cold start first or maybe second kick. Reasonable advance and no air leave - that stays fully open at all times.
2) Warm starts variable. I feel this is partly due to getting my "swing, release" movement right...but that can't be the problem all the time. I am coming to the view that it is fuel evaporation related, but sometimes a plug change seems the only cure, but the one I take out is (hot!) dry but (maybe) not sparking. That said I could also simply be letting her cool a little more by spending g the time doing the plug swap.

I have ow realised the most important thing though...if I have faith and patience she will start!

One factor which may be more significant for my experience is that I am in Singapore, so even cold the ambient is around 30C which I guess explains the lack of need for the air leaver :-)

Richard

email (option): dickie.bobbie@hotmail.co.uk

Hi Richard..You won't need a 'choke' at all once the engine has run in those temperatures...and probably not even at first start up. Just a quick 2 second depression of the 'tickler' should be plenty in the mornings....
When the engine is warm don't use any choke or the tickler. Also leave it fully advanced...IF it kicks back then just apply the minimum amount of retard to stop it kicking. The point is to keep it as advanced as possible.
Don't use a 'kick and twist' technique on the kickstart and throttle. Leave the throttle closed, kick the bike over and when it fires 'catch' the engine revs with the throttle..I have found they don't like starting if the throttle is opened too prematurely...
Also, bring it up to TDC on the compression stroke and then use the valve lifter and kickstart to get the piston just past TDC...Ensure that it is ONLY JUST past TDC...this may take a little practice. Then give it a good, quick, swing using your body weight.. and don't be afraid of it....Ian

email (option): ian@wright52.plus.com

P.S...And you will definitely need an insulation spacer between the barrel and carb if you don't have one...Tufnol or a material with similar properties, at least 1'4" thick..Ian

email (option): ian@wright52.plus.com

Hi Ian

I've been wondering about a spacer, that may help. Hot or cold the choke isn't needed, I'm blessed with the heat :-)

Now you mention the throttle I guess I had noticed that things were better if I left it alone until I have something to work with. I'll concentrate on that part of the operation next - it's all learning - I must have read up on how to start a bike of this vintage so many times when I was younger (Pitman Book of the Red Panther...) but reality is a little different!

Many thanks :-)

Richard

email (option): dickie.bobbie@hotmail.co.uk

Hi Richard...Just to be clear...From my experiences I would say you must fit the spacer to avoid fuel evaporation problems....Ian

email (option): ian@wright52.plus.com

Hi Richard,

I can machine a spacer for you if you so require as I have a full sheet of 1/4" tufnol after machining a spacer for my bike, please email me.
They definately work well and helps stop the carb spitting back.
I agree entirely with what you are saying in regards to having experience with these bikes, as I'm also on a huge learning curve, but thankfully mine starts 1st kick almost every time now.

Julian

email (option): 79aust@sky.com

Hi.
One reason of bad starting could be side stand. My carb seems to flood every time I stop the bike and lean it on the side stand. Now if I want to start it right now, mixture is obviously too rich.

email (option): kalle.tikas@gmail.com

Hi kalle
Dont discount a worn slip ring - it creates similar symptoms to a condenser , but is very difficult to diagnose

When warm, it can earth through the ring to the armature, also cracked insulator creates the same

Easiest is to consider a rebuild either way

Job

email (option): Jonnyob1@googlemail.com

Hi

Good experiment today. Brief stop for refreshing juice after good run. Engine and carb still nice and hot for restart. Lots of kicking and no joy. But rather than resort to plug change I was just patient, did a bit more tickle, gave her a minute after that, so that I could feel that the carb body had cooled more, and success, with a good steady tick-over direct from the start. Other times the tick-over has been poor,which maybe indicates that the carb is still too hot?

Also on the outbound run in clear sunshine as we got to the end, 30mins or so of mixed stop start and slow clear runs, she was feeling and sounding "breathless", you know where you "think" the engine is going to cut-out. Could just be me worrying, as we didn't cut out!

There is a spacer between carb and inlet, but it is at most 1/8th inch...so a thicker more insulating spacer sounds like a good plan. Wonder what the forces did in the heat?

Richard

email (option): dickie.bobbie@hotmail.co.uk

My 16H will start first kick if I tickle the carb until I see petrol, then just past compression and retarded ignition, with the throttle opened fully. It even likes this when hot. It seems to like a lot of fuel.

email (option): horror@blueyonder.co.uk