Help troubleshooting kickback & stalls after starting (2016)

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elefantrider

elefantrider

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This is a '71 with less than 4500 original miles on its motor but it has had a cosmetic rebuild so it has been apart before.
Has a powder coated frame and cradle.

Bike will start but not run very long. When throttle is cracked it wants to die.
This is in 70 degree weather so no choke is used.
Bike has a nasty bad kickback, the worst I have experienced.

Points plate was found at the end of adjustment, cannot retard any more.
Float height is the same in both carbs, maybe set a little low as one side is harder to tickle.

I plan to remove the points plate today and check the auto advance is lubed and free.
 
elefantrider said:
Points plate was found at the end of adjustment, cannot retard any more.
Click to expand...

If you've run out of adjustment on the points plate then you need to reposition the AAU.
 
Thanks. It has been a while since I've messed with an AAU and points.

If I am out of retard (counter clockwise) adjustment on the points plate, I need to remove the auto advance, marking position in the process, and reposition it about a 1/8 to 1/4" further in the opposition direction (clockwise)?

What lube is recommended on the AAU?
 
elefantrider said:
If I am out of retard (counter clockwise) adjustment on the points plate, I need to remove the auto advance, marking position in the process, and reposition it about a 1/8 to 1/4" further in the opposition direction (clockwise)?
Click to expand...

Yes, about 5-10 degrees clockwise should do it.


elefantrider said:
What lube is recommended on the AAU?
Click to expand...

According to riders manuals: "Retinax A" grease "for the contact breaker pivot post and cam.....and three drops of engine oil to each lubricating felt...."

(Shell Retinax A is/was a multi-purpose grease)
 
Do the simple things first:

-remove the air filter, then use a mirror if you have to, to watch the slides go up and down evenly when you twist the throttle. Pay attention that the needles are moving too and make sure they feel like they are engaged in their circlip properly and both seated in the inner throttle body at the same height.

-start the bike and spray some carb cleaner at the outside of the intake manifolds to see if it makes the bike stumble (due to an air leak)

-run the bike, then twist the throttle as you pump the bleeders to see if that keeps the bike from dieing

-clean the kill switch if you have one...

.... probably more simple stuff too that I'm forgetting....
 
Without removing the AAU, I was able to retard the points plate a bit further. Still has kick-back but got it running for about 5 seconds.

I have the pilot jet screws out about 1.5 turns, but strangely that puts them at different depths on each side.
 
elefantrider said:
I have the pilot jet screws out about 1.5 turns, but strangely that puts them at different depths on each side.
Click to expand...

Check a throttle-stop screw hasn't been fitted in one of the pilot air screw holes?

The Amal pilot bush can block, so one or both may need cleaning?
 
Ok. Will do that.

Now got bigger problems. It seems the transmission had its last kickback. The pawl gave up the fight. Getting the ratcheting, non-engaging, don't think it be anything else but the pawl? Can the pawl replacement be done on the bike? How long a job?
 
elefantrider said:
Can the pawl replacement be done on the bike?
Click to expand...

Yes.

elefantrider said:
How long a job?
Click to expand...

I don't know how fast you work, :wink: but outer and inner gearbox covers need to be removed.
 
And, once the new pawl is in, be sure to find the cause of the kickback before trashing another starter pawl! Does the AAU snap back properly when manually rotated by hand? Mine hangs up on occasion, requiring pulling the points plate and cleaning the AAU shaft to cam interface.

Nathan
 
What are the minimum parts needed for this job, and those that should be replaced as a precaution?
 
elefantrider said:
What are the minimum parts needed for this job, and those that should be replaced as a precaution?
Click to expand...

http://www.nortonmotors.de/ANIL/Norton% ... 08&Part=20
http://www.nortonmotors.de/ANIL/Norton% ... 08&Part=21
http://www.nortonmotors.de/ANIL/Norton% ... 08&Part=22
http://www.nortonmotors.de/ANIL/Norton% ... 08&Part=23

Maybe replace the selector springs too.
http://www.nortonmotors.de/ANIL/Norton% ... 008&Part=4
http://www.nortonmotors.de/ANIL/Norton% ... 09&Part=10

Plus any necessary gaskets and seals.

This would also be an opportune time to inspect and if necessary, replace the drive-side layshaft bearing if it's found to be the standard 6203 ball bearing. :)
 
Thanks a ton. What is the best layshaft bearing to use these days? I have seen a few mentioned on here. Something about a German one being best?
 
elefantrider said:
Thanks a ton. What is the best layshaft bearing to use these days? I have seen a few mentioned on here. Something about a German one being best?
Click to expand...

Either the NJ203E roller bearing (AN part 06-7710) or the FAG 6203TB.P63 ball bearing.

http://www.doov.com/apps/nortoncompanio ... ng-upgrade
https://www.oldbritts.com/gearbox_d.html
https://www.oldbritts.com/gearbox_a.html

If you search the forum using the term "layshaft bearing" you will also find more information.
 
Replaced the pawl but decided not to replace the spring, pin and plunger which seemed fine.

Disliked how the replacement pawl pin was shorter than the factory original one.

It did not sit flush with the kickershaft flange, so put the original one back in.
 

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Determined the AAU was stuck open. Sprayed it while still in place with some WD40, then Teflon spray but weights still aren't closing 100%.

Shouldn't the weights snap closed each time? . I am thinking of soaking in gasoline and re-lube until they do. Seems they close only 80%, leaving a last bit open.
 
elefantrider said:
Determined the AAU was stuck open. Sprayed it while still in place with some WD40, then Teflon spray but weights still aren't closing 100%.

Shouldn't the weights snap closed each time? . I am thinking of soaking in gasoline and re-lube until they do. Seems they close only 80%, leaving a last bit open.
Click to expand...

An advance unit stuck full on will definitely cause it to kick back. So will flooding, so make sure the floats are set to the correct level and the float needles seat well enough to stop the flow of fuel.
 
elefantrider said:
Determined the AAU was stuck open. Sprayed it while still in place with some WD40, then Teflon spray but weights still aren't closing 100%.

Shouldn't the weights snap closed each time? . I am thinking of soaking in gasoline and re-lube until they do. Seems they close only 80%, leaving a last bit open.
Click to expand...


Do they close the last bit when you turn the engine?
 
If the AAU is not closing fully then either the springs are slack and need replacing or the slots are notched and the pins are sticking in which case you need to file the notch smooth or replace with a new AAU, as the cost of a new AAU is close to that of Electronic Ignition then you may prefer to go EI.
 
Now I remember why I got rid of the stock points set up 37 years ago, I had the same thing happen all them years ago and finaly after so much mucking around to get the bike running right found there was wear in the AAU that was causing all the problems, I replaced it but not long after I put a Boya EI and never looked back.

Ashley
 
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