Another Stator/Rotor Question

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Since the stator studs are not directly screwed into the crankcase, to me, unless bent, you don't "correct" the stator studs with a hammer. Before fully tightening the three bolts that hold the inner chaincase to the crankcase, mount the rotor and stator and get the clearance right. Then finish tightening and recheck. If OK, bend the lock tabs and finish the chaincase.
 
To the original question. If you use a flap wheel to remove a little bit from the inside of the stator, I don't think you need to worry about coating it with anything. Should you want to, it would need to be something like a spray on electrical lacquer that could stand high heat, oil and be very thin. Unless you start contacting electrical windings, which would be a very rude surprise then I wouldn't be concerned about it. I might be tempted to polish the area I worked on to help it stay clean.

As for how big of a gap...This is sort of like asking how big of a gap can you have on the lawn mower coil and still get a spark. It might be a lot wider than ten thou but why degrade the spark by making it wider? You could run an experiment on the lawn mower moving the coil and report back how wide it got before it failed to spark!
 
Well I'm finished and moving on. Could not find a flap wheel in Enterprise Al with a Lowe's and a Harbor Freight. Ended up "carefully" milling out the stator with a sanding drum. Multiple re-fittings of the stator and got .010 all around for all positions of the crank. Now on to the wiring. There's a lot of Loctite in this project. In the end, I did not see anything that required recovering.
Thanks for the advice.
 
disaster can happen if the rotor touches the stator, besides the cost of replacement. and a very powerful stink that stays in the primary for a long time. If it goes up in smoke your day will definitely be ruined.

I have run them successfully at .006 but it makes me nervous. I usually take a dremel with a sanding drum to trim the tight side and use several fit-ups. turn the motor over to see if the tight spot remains constant.

Bashing the studs with a hammer is asking for trouble, plus the stator will now be much more difficult to R&R. And there will be tension locked up in this unit waiting to find a way out.

drilling oversize holes works but now the potential of the stator loosening and sliding into the rotor will always be there.

I would REALLY like to know the maximum gap allowable and how the charging is affected at say, .008.....010....012.
 
Somehow a mallet morphed into a hammer. Who is bashing the studs with a hammer?o_O A boilermaker bashes things to make items fit. Apologies to any boilermakers out there.:D A mallet is quite different.
cheers,
Thomas
 
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Ref functionality of more clearance. I had 20 thou skimmed off a rotor once and it did reduce the output of the alternator. Couldn't say by how much though.

Ian
 
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I agree with maylar,
IMO the rotor can expand when revving near to the red line, If it means skimming a few tho off in a lathe or removing a few tho off the stator, then do it any contact between these two components is bad as one will ruin the other, and if it’s the stator this works out expensive. So it must be avoided at all costs.
 
Contact WILL cause smoke and then fire. Anybody remember the date run on the rotors that were prone to
cracking and losing their magnets? We talked about it at one time.
 
Bernhard said:
I agree with maylar,
IMO the rotor can expand when revving near to the red line, If it means skimming a few tho off in a lathe or removing a few tho off the stator, then do it any contact between these two components is bad as one will ruin the other, and if it’s the stator this works out expensive. So it must be avoided at all costs.
Click to expand...

Much more than the alternator is at stake. When mine failed pieces of the rotor got jammed in the primary chain. Chain broke, and bent the gearbox mainshaft. Put a hole in the inner primary cover, and sheared off the timing scale on the outer cover. Catastrophic failure, indeed.
 
Saber13 said:
Well I'm finished and moving on. Could not find a flap wheel in Enterprise Al with a Lowe's and a Harbor Freight. Ended up "carefully" milling out the stator with a sanding drum. Multiple re-fittings of the stator and got .010 all around for all positions of the crank. Now on to the wiring. There's a lot of Loctite in this project. In the end, I did not see anything that required recovering.
Thanks for the advice.
Click to expand...

31 posts and not one person bothered to measure?
How many actually own AND work on a MKIII?
see my by line below....

old fashion real oem lucas stator(4-71) ID 75mm.
Aftermarket 3 phase stator ID 74mm.
I'll be doing typical corrective "fettling" on my 2 aftermarket stators before installation on my MKIII and combat, leaving the sledge hammers in the tool box.
 
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Smoke pouring out, zero power output, stench beyond telling, charred internals.
Bike parked in the barn for two years in disgust. Gap had been carefully checked.
No loose bolts or nuts. Not hit by lightning or stray panzerfaust round.
Next question....
 
MKIII
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The Mk3 has separate primary [20] and rotor [24] studs so the "bent stud" method is unlikely to work (and the Mk3 manual instructions appear to be a carry-over from the previous manual) as the laminated ring of the stator locates in the outrigger plate with no room for adjustment. Only the outrigger plate [18] fits on the four primary studs and it is also located to the primary case by a stepped joint at each of the four mounting points (& 1 dowel,19) again with no means of adjusting the outrigger's (therefore, stator's) position relative to the rotor unless 'modified'.

https://andover-norton.co.uk/img/imagescaler/ce/ce50462b69be556fc4a80ad3592e899a.jpg
 
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Well, back to (Sort of) the original discussion...since there is NO adjustment available in the stock parts, Doesn't that pretty much tell us that it was not an issue on the original bikes coming out of the factory. What folks did to them afterwards - with aftermarket parts - is a different deal, as are modern "replacement" parts that although they are claimed to be the same, may not be. IOW, is a current AN/Lucas rotor exactly the same diameter as 197x Lucas rotor?
 
MexicoMike said:
Doesn't that pretty much tell us that it was not an issue on the original bikes coming out of the factory.
Click to expand...

I have a spare Mk3 inner primary case and an outrigger obtained from separate sources. The outrigger doesn't quite fit the primary case which could suggest some individual fettling may have been done at the factory.
 
I have installed what seems like hundreds of stators over 40 years and the tight spot is usually (not always) towards the rear of the bike...1 o'clock to 6 oclock. any ideas?
 
My bike was sold to me because of rotor/stator misalignment and the frustration it caused the previous owner, because he couldn't figure out why his bike always died whenever he went somewhere. I aligned the original stator by using the "slightly oversized drill method" to enlarge the mounting holes, and was able to reposition that stator. When I bought a higher output stator, (not 3 phase) I had read enough about bending the studs to be convinced that the mounting bosses would survive few gentle raps on the studs to adjust the gap, and they did survive that process without any issue.

It should be mentioned that in the case of my 70 commando style primary case, shimming the inner primary stand off stud improperly causes the inner primary case to deform it's shape which effects the position of the stud mounting bosses, and then the position of the stator bolted up to it too. So, the stand off bolt adjustment is critical to get right before a person resorts to all the different methods of adjustment.
 
Agree on the 1 o'clock area being tight. Just my experience on several bikes.
 
dynodave said:
31 posts and not one person bothered to measure?
How many actually own AND work on a MKIII?
see my by line below....

old fashion real oem lucas stator(4-71) ID 75mm.
Aftermarket 3 phase stator ID 74mm.
I'll be doing typical corrective "fettling" on my 2 aftermarket stators before installation on my MKIII and combat, leaving the sledge hammers in the tool box.
Click to expand...

The above in red from dynodave seems to be an/the answer? or am I missing something?

If the original OEM stator is 75mm and the aftermarket stators are 74mm then . . . . . . . .

I don't have any aftermarket stators on the bench so can't check myself, would others have some stators they can check the internal diameter so we can get more data?
 
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