Dear Forum

God Help Me!! I have acquired a beautiful M20 that has been reconditioned but I have no ideas what I am doing.

Can someone please help me with regards to the advance and retard lever. When I got the bike I struggled to start it and it was obvious that the carb was blocked. Having unblocked the carb and coated the inside of the tank it starts Ok now (if you can call it OK on an old machine) the problem is that I am confused about the retard and advance because it seems to contradict everything people have told me.

Basically, if you imagine that I am sitting on the bike it would appear that the engine is fully advanced when the lever is pushed totally away from me. To start the bike i seem to have to pull the lever towards me and then when it fires push it away again. This is the opposite of what I have been told to do. It seems to be advanced when the cable is slack.

Can't work it out!!!!

Also, does anybody know where I can get a front number plate for a 1941 bike?

Thanks

Andy

email (option): Andy.hunter@brandsolut.co.uk

Hi Andy...Look on the 'technical section' of the website under 'ignition timing'...There is a lengthy article there that explains why you have adv/rtd, how it works on the bike and how to tell which way your adv/rtd lever works (ie which way is advanced and which way is retarded)..This is dependent on the spec. of the magneto you have fitted...Ian

Hi and thanks for the reply.

The points turn clockwise when you turn the engine and the adv/ret cable enters from the right of the magneto/points

With the lever pushed away from the rider the cable is slack. With the lever pulled towards the rider the cable is tight and it pulls the plate behind the points anticlockwise.

Which one is advance and which knew retard??

email (option): Andy.hunter@brandsolut.co.uk

Hi Andy,


As you mentioned, the points block is turning in a clockwise direction,
So when the plate is pulled, you advance the ignition,
By pulling the cam plate anti clockwise, so the points are opened sooner.
When fully advanced, and with the points adjusted to the correct gap,
The points should start to open at 11mm BTDC.

If you slack the cable, the plate moves clockwise, so the points block
Has to travel some more in order to reach the high point on the cam plate,
(Located under the spinning points block, the part which moves by cable)
Which pushes the cam follower/tappet which in turn opens the points.

Secondly, you can find some more info also here:

http://pub37.bravenet.com/forum/static/show.php?usernum=3155626639&frmid=16&msgid=1325423&cmd=show

Good luck,
Noam.

email (option): noam10@gmail.com