After rebuild start up!

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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clive
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Joined: Mon Jan 01, 1990 12:00 am
Location: LONDON UK

Re: After rebuild start up!

Post by clive »

Well having watched the video all i have a number of suggestions. Firstly your starting technique looks like a twin one to me ie bring it up to compression and stamp on the kickstart. This makes for difficult if not impossible starting in my experience. The valve lifter is there for a reason. My starting technique is to bring it up to compression. Allow the kickstart to return then using the valve lifter push the kickstart down about 2/3 of its travel. Allow it to return to the top and then give it the long swinging kick.
Next point if it has not started by three kicks i would flood the carb more. There is little point in my view in just kicking and kicking if it wont start you need to try something else. Having flooded it further if it does not start in a couple of kicks then its time to take the plug out. If it is not wet then there is something wrong.
I have not kept up with all the advice but i would be looking at the following. Timing is it spot on 1/2 inch before tdc with the automatic advance held fully open. Do the points start opening when the two pushrods both have free rotation (ie on the correct tdc).
Are you using an ngk plug chuck it and fit a champion from a reputable dealer. Is the carb pilot jet and the little drilling clear of muck? Do you get a good fat spark with the plug against the cylinderhead?
Good luck you are nearly there.
clive
if it ain't broke don't fix
SPRIDDLER
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Location: WEST SUSSEX UK

Re: After rebuild start up!

Post by SPRIDDLER »

Well, to me it didn't sound like it was firing at all.
Certainly after so many kicks and assuming there's a good spark............
As Clive mentioned I'd flood the carb more, kick a couple more times and see if the plug was wet. If it wasn't wet (especially if the bike had been standing unused for a while) I'd whip out the pilot jet and check that it was clear - (10 min job). If the plug still wasn't getting wet and the pilot jet was clear I'd force aerosol WD40 or carb cleaner through the tiny pilot drillings in the carb body to make sure they were clear.
Monobloc pilot drillings (511x640) (359x450).jpg
If the plug was getting wet (assuming ign timing was correct on the compression stroke) and even if the plug was sparking well externally I'd fit a new Champion plug.
It's not easy to tell, but it does seem that it kicks over rather easily but nevertheless Clive's starting technique is the usual/best procedure.

EDIT:
To confirm that the plug is sparkling under compression, remove plug, put 2 teaspoons of petrol in the plug hole, replace plug and lead and kick. You should at least get some firing even if the carb is blocked.
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NaughtyNetley
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Joined: Fri Dec 28, 2018 12:09 pm
Location: Cornwall

Re: After rebuild start up!

Post by NaughtyNetley »

I'm having a clean out of the carb, again, as it has been apart and cleaned when I stripped the bike.
I discovered that the throttle adjustment screw at the bottom was missing. I have a spare carb as my bike has the 500 top end on and have used the screw from the spare carb. I presume this would have an effect on the air mixture?
I have timed the ignition with valves closed on the compression stroke at tdc and and the points cam follower just about to open the points.
I can't see how to open the auto advance as it is behind the points plate.
Please excuse my ignorance.....
I will go and give it another hopeful kick over using the method described in a previous post and use the decompressor!!
NaughtyNetley
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Joined: Fri Dec 28, 2018 12:09 pm
Location: Cornwall

Re: After rebuild start up!

Post by NaughtyNetley »

I followed advice re starting procedure after fitting throttle stop of course.
Started first kick, hurrah! you cannot believe how overjoyed I am :P
NaughtyNetley
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Location: Cornwall

Re: After rebuild start up!

Post by NaughtyNetley »

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clive
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Joined: Mon Jan 01, 1990 12:00 am
Location: LONDON UK

Re: After rebuild start up!

Post by clive »

well done told you you were nearly there!
clive
if it ain't broke don't fix
JEAN-NOEL
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Location: FRANCE

Re: After rebuild start up!

Post by JEAN-NOEL »

Well done ! This demonstrates the usefulness of the forum to have issues solved...
I think you have now to check ignition timing according your manual with the auto advance wedged fully Advanced, and check if this device moves freely.
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