Hello, im from argentina.
I´d like to find a solution to an issue.
When i firts strat my m20 it gives me no trouble...she is almost first kicker...
But she heats and i stop her, then she gives me a headache..
The carb should be mounted far from the headcylinder ? The amal carb needs a spacer ?
Someone told me that this happends because the gas runs hot. Is that possible ??
Best regards.
lucas

email (option): vespeed

Just my opinion, of course; while it is possible and even likely, that the fuel held in the carb and feed line is boiling away from the engine heat when stopped, it is much more likely that the hot starting problem is due to a weak ignition spark.

Has the magneto ever been rebuild, and more specifically, has the magneto condenser been replaced at some point in recent human memory!?

JDE

email (option): teladelujo@msn.com

hi lucas, with a name like yours you should know all about ignition systems,(only joking).
yes there should be a thick insulating gasket between the barell and the carburettor,about 1/4'' or 6.5mm,this is essential,however as barry points out the magneto or other parts (condenser) may be at fault,hope this helps
cheers rick

email (option): richardholt@rocketmail.com

Quote.. "Has the magneto ever been rebuild, and more specifically, has the magneto condenser been replaced at some point in recent human memory!?"
Both of them done...
I can´t find a solution !!! I´m going crazy...
Thanks..
Lord of darknesssssssss

email (option): vespeed

I had a similar problem with my bike many years ago. It wasn't the ignition that gave me the problem, it was the carburettor. I had build my carburettor from parts not knowing that the nut that keeps the jet block in place comes in at least 3 sizes. Only having he tallest I fitted that and the bike started ok but always had the problem of overheating. With this tall nut the float chamber sits to low giving a poor mixture with overheating as result. I tried everything until I found out that it needed the smallest nut. Now it runs fine.

Henk

email (option): ahum@quicknet.nl

As a general rule. The short nut is for SV's, a longer nut is for OHV's. But this is not always the case.
DAMHIK. Ron

email (option): ronpier@talk21.com

Never to old to learn, but at the same time I always forget what DAMHIK means

email (option): ahum@quicknet.nl

DAMHIK (Don't ask me how I know)
I ran my WDCO with the wrong nut for years. Final straw was the steep hills on Dartmoor this year.

Ron

email (option): ronpier@talk21.com

It took me quite a long time too to find out what was wrong. I did all I could think of, thick insulator, I relocated the fuel line as it's originally pretty close to the cylinder, bigger main yet etc etc.

I went NUTS when I found out what was really wrong

email (option): ahum@quicknet.nl

Henk it is usual to have the short nut on M20's and most Nortons,and the medium nut on most others, the third nut was I believe only used on Vincents so is very rare to locate.Here in Australia we have problems with the petrol getting too hot if we don,t use a 1/4 inch spacer between the carb and the cylinder. John.

That could indeed be Vincent, I bought a small box of carburettor parts a while back and some of these parts were also Vincent I found out. I should take a better look in that box, there might be more.

Henk

email (option): ahum@quicknet.nl

He's already retired young.. ...Ian

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

You are correct !!
My carb is runing with the middle one..
I have 2 amal carbs decorating my desk and they are like the one i have runing... I´m doomed !!
I will try to find the right one..
In any case, you guys have been all extremely helpful and solidary !.
Best regards.
Merry christmas
Lucas




My girl "Rita"..

email (option): vespeed

Lucas. You need only change that nut for the correct one. Google Amal (Burlen Fuels) here in UK. You can buy a nut and maybe put a few more new bits and gaskets in your carb. Check on line that you have the correct jets/ needle/ slide etc.
The carb at the bottom right of your picture,looks like a model 76. Which is more suitable for a pre or early war machine. Ron

email (option): ronpier@talk21.com

Thanks for that info and picture of the three nuts Henk... Wonderful bit of useful information, will rush out to look at what I have. I suspect the middle one is most common though. Cheers.

Great info on the union nuts Henk. I often wondered why the engine would over heat while running on the stock jetting. Just checked, I have the same mixing chamber union nut as Lucas.

I have been trying to work out what was wrong with my bike for a while.
I am also running the middle nut.
I am relieved.
Cheers

email (option): acmeaircon@hotmail.com

Hi Henk,
To compensate for the larger nut(i have the middle size)could I just raise the float level to suit by cutting a small groove in the needle higher than the old one? There is plenty of clearance inside the float chamber to do so.
I am guessing about 5mm.

email (option): acmeaircon@hotmail.com

The Norton in the forum picture seems to have the middle nut..? Or am I wrong..?

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

Henk,

I think you fixed three cycles without turning a wrench. This is what a forum is all about! (Granted someone else has to turn the wrench.)

cheers, Scott

Raising the float level does not work so I will have to hunt down a short nut.
Interestingly the exploded view in the manual is of a medium size nut.

email (option): acmeaircon@hotmail.com

Yes Jeff. I have noticed that most manufacturers don't show pictures of the relevant model carb/mag/regulator etc in the workshop manuals. They all use a standard line drawing. Ron

email (option): ronpier@talk21.com