[Arizoni]

If your getting strong kickbacks it indicates the ignition is still advanced a bit too far when it isn't running.

Like Creaky mentioned, this could be caused by weak advance return springs in the centrifugal advance.
You need to test the springs.

A quick way to test these springs is to gain access to the points cam and possibly the centrifugal flyweights.

Moving the flyweights outward will advance the cam.  Usually, you can just rotate the cam in the advanced direction with your fingers and the flyweights will move out a bit.

Anyway, advance the points cam a bit (against the spring pressure) and then let go of it.

After the springs have done their job, try to move the points cam further in the "retard" direction.
If you can do this, the springs are either weak or stretched and they should be replaced.

After doing this, if the springs moved the points cam to the fully retarded position (like they should do), the points timing needs to be adjusted further by moving the plate.

[creaky]

Blas, dginfw is right about starting the engine. If you have an ammeter and a decompression lever working it is easy. Ignition on, pull decomp lever and slowly push kick start till ammeter goes from discharge (left) to centre. This means points have just opened. Now when you kick it after,releasing the decomp lever, the flywheel has enough momentum and won't kick back. You probably don't have electric start or you would have broken the sprag clutch by now. (no electric start means no sprag to break) Every bike is different as to how much throttle to give it to start and if the choke is needed and for how long. I use full choke (if cold start), smidgeon of throttle, (remember how much a smidgeon is) and kick. Soon as it starts I can release the choke. Awaiting the next installment.

[blasphemous]

Creaky,
Arizoni was right. I was a bit too advanced. I retarded it just a smidgeon and it now starts like a champ. Also my springs might be weak, The bike sat for 14 years afterall. There is a little movement in the return direction.  It starts and runs fine now. I will eventually change the springs. You mentioned that you changed it with replacements from Hitchcocks. How hard was the job ?

[creaky]

I did not change them myself. The bloke who rebuilt my motor did it but I think it is a simple matter of removing the plate and you will see the weights and springs. Then, I guess just change the springs. Hitchcocks site may give more info.

[blasphemous]

Guys,
I am not sure why I keep getting spit back from the engine into the carburetor. It is so bad that it blows the carburetor off the engine every single time. The bike mostly starts and runs well. But after stopping and starting again it blows back hard. The kicker kicks back, but very rarely. It is mostly this loud noise with white smoke coming off the air filter and the carburetor blown off the rubber housing that mates it with the engine intake. WHY WHY WHY ?

I read this in the Snidal manual:
"Too-lean carburetion can cause spit-back from the carburetor - sometimes bad enough actually to blow it off the engine - and hard starting"

Could this be the reason ?

Also one thing to note here is that this always happens on a warm engine. Cold always starts fine. When the bike is hot and re-started that is when it causes this problem.
 

[dginfw]

Possibly an air leak causing it to go lean when its hot.  Check the carb manifold for any leaks. Also make sure carb is not staying a tiny bit open.  On my stock carb, if the top was screwed down all the  way the carb slide would bind and get stuck.  while the air filter is off look in carb throat to make sure slide is down

[ace.cafe]

Every time that ever happened to me,  the rubber intake manifold hose had a crack or split in it.

[blasphemous]

ok it tuned out I was not getting the right fuel mix into the bike. I tuned the pilot and stop and it now starts well.