Stator clearance

Early stator mount with 1/4" studs and later stator with 5/16"  holes,  You need what no one is supplying ,     stepped studs. or have the stator mount drilled out and retapped 5/16  and probably have to have studs made as well, or use bolts (not ideal but works).. You could get some 1/32" thick sleeves made (1/4" bore). Your studs appear bent(crash damage?) .I never did find any new ones with the right threads but things may be better now??!. Also possible fake Lucas stator with poor accuracy and or wobbly rotor (tight key?).Missing stud and your wires in the wrong place too. Too many bodges on our poor old bikes.We are all going to need a new stator sooner or later,perhaps the club could get some studs made as the Normal dealers are not interested in solving problems and just want to score a profit on the .Alternator??.

On my Commando - I remove the studs and waist them (on a lathe) a long the length that the stator sits (reducing the diameter by about 0.025''). This allows the stator to move around the studs and I can usually achieve a between 0.008'' and 0.010 '' gap in all places between the rota and stator.

Regards - Paul. 

A small amount of clearance is usefull,  1/16" is too much and can allow things to collide and mayhem to ensue.

Something is way out here, 0.8mm = 0.032'' so even if you create more space on the side that is now tight it is not going to be efficient, are your figures correct? 

Old size rotor?., Perhaps clearance won't be an issue after all  ,along with overcharging !.When you do get a new rotor a shim behind it will centralise the rotor in the stator.

hello members  well yes i do agree with post above  the air gap between rotor and stator is 8 thou all way round the stator , and you may find that you have to do some engineering to make thing,s fit correct in our days  as Deals are not interested in solving   your problems  as most of these parts where made to be a universal fit,  for all british motorcycles  ,But I am now looking at Pit bike rotors and magnetic CDI ignition  and coils for lighting with a 65w out put just enough to charge a 12v battery,  with some lathe machining to the centers to fit a norton crankshaft rotor end shaft  with a base plate made up so you can there for set the ignition to 29 degrees before top dead center, and fitting this will need this plate to fit the old stator mount and to be sealed off for oil with in the chain case,  but you will have a ignition   every 360 degrees  and no need of a battery on a CDI its self generating     then you can fit in place of your old mag a self starter  just one of my ideas  but these pit bike fly wheel Cdi ignition system are cheap only cost just over 20 quid and with some engineering you can make them fit your norton and have a reliable ignition system    that cost less then anything on the after market,                        yours  anna j 

Despite the above something is still amiss. Do the maths, it sounds like the rotor has been machined. If the 0.02mm gap is adjusted to roughly 0.008'' then you would have reduced the 0.8mm gap by 0.006'' there maybe nothing wrong with the stator. Achieve the correct gap all around an try it, it could still be the cheapest option. 

The stator looks ok. They are all like that now with 5/16 holes,  If there is more than about 12 thou clearance all round you probably have an old small rotor which is useless with the new stator. Once you have a matching pair you will have to sort out the loose studs as the clearance between rotor and stator is so small that the thing will wreck itself otherwise.Old rotors were 70mm I think.New are 74mm , not to be mixed up. Do not rely on the ally mount to hold the stator still, close fitting studs ARE needed.

I have just done the same job on my Dommie, fitting a new stator mount casting and alternator stator and rotor. Amongst the various issues that invariably crop up, I found that the rear face of the mount casting was fouling the screws holding the primary inner case to the crankcase and that flash on the casting was fouling the primary case. A little filing  on the rear face of the casting solved both issues and allowed the casting to fit as designed against the crankcase face and cleanly on the spigot section. It took a bit of fiddling with it all before I realised that the fouls, though hardly noticeable, had a big effect on the clearance around the rotor. I went from a wishful thinking 1 1/2 thou clearance to a tight 10 thou at the worst point on the rotor. The other practice I have found to help (once you are nearly there on the clearance) is to insert appropriate feeler gauges at each of the stator poles as shims whilst you lock everything up (checking that they don't get locked in as you progressively tighten everything). This has worked well on both my Commando and Dommies over the years.

One final thought re alignment of the rotor and stator, do you have the  spacer ( more like a very thick washer) in place between the engine sprocket and the rotor? It is assembled to the crankshaft before adding the rotor key and the rotor - the usual suspects have it in their parts lists; p/no 23738 for my 650 though it may be worth consulting the parts book for your model to check.

Be very aware here, if you waist the studs and gets lots of nice centralising, you could also very easily have the stator 'slot' back to where it was, so I would not have waisted studs. Sleeving could be in order.

I also the spell checker on the forum is still CRAP crappy crapulus etc,

AO