Chaincase fitting

Taking my time going through 72 Combat.
Ordered up all the shims for the chaincase, clutch and rotor.
Having had issues in the past with Stator clearance I ordered up new studs,washers and nuts. Wanted to start with new, straight studs.

Carefully set the inner case withe new felt, gasket. Inner chaincase rocks, glad I got some shims. Install screws to check clearance, Now it's fine with the stock spacer.
No additional shimming needed. The gasket crushed it into position.
Remove scews one at a time and locktite with 518 with new lock tabs.
Looks good so far.
Set a new clutch circlip, new crank key for the front sprocket, mock up the front sprocket and clutch without the chain for alignment with straight edge. It's out.
Takes one small (.032) and one large (.048) shim for the clutch.
While I'm here I install the rotor and timing disc to verify marks.
Set crank at 28, install outer cover, outer cover is a little fiddly to go.
Rotor is at 32... Pull cover recheck crank again with disc, reset cover, again a little fiddly, rotor is at 32 again. I guess that's it, it's out.
Pull the outer again, why is it so fiddly?
Notice the center stud is not sitting in the center of the inner case. Innercase is sitting on top of stud. Hmmmm, not enough for me worry about for disassembly.
Pull the front sprocket and clutch, reassemble with chain. Install two rotor shims that came off at disassembly, install spacer, key, rotor, bolt and washer. Torque.
Set new stator studs, spacers, stator, washers, nuts.
Check clearance @ .008 with brass (non magnetic) feeler gauge.
It's tight on the bottom. Spin it around, check again, Consistently tight on bottom.
F#&^%*(...... Stare at it for awhile, thumb through manual. Manual says to bend the studs. Been there, done that, don't want to. The good part is it's consistent on the bottom. I've gone through the whole engine including crank work.
Stare at it some more, get pissed again. Wife brings out some lunch, (Great Wife BTW)
stare at it some more while stuffing my face. And there it is. If the inner chaincase could rotate up a little on the center stud, it would lower the stator position. Just need to loosen the inner screws, with the lock tabs that are sitting behind the sprocket that's attached to the chain. Got it done, centered the stud and VOILA!!
Min. .008 clearance all around.....
The reason for all this long wind is Commando's are very fiddly. Takes some patience and perseverance to get them right. I've done many, many primaries over the years, this is the first time I took my time to get it right.
With the rotation of the chaincase, I'm betting the timing mark changed.
I'll check again and report back.
One question, what is the proper placement of the rotor in the stator.
I just reused the original shims, looks like it could come out some more.
Is there a magical placement?

Fettling = Fiddly !
Yes you can bring the rotor out more to enjoy better A.C. magnetism with the stator . But why not just bring the stator itself inwards by removing material from the 3 stud spacers or find slightly shorter spacers ?

IF the rear of the chain case went up than your timing mark will be even farther out. the alt. rotor spacing is not even close to having to be centered in the stator. if you try to do this it will not clear the timing scale long before it is centered

bill said:

IF the rear of the chain case went up than your timing mark will be even farther out. the alt. rotor spacing is not even close to having to be centered in the stator. if you try to do this it will not clear the timing scale long before it is centered

Click to expand...

That's what I was thinking.
I do need to check it again to know where its at.
I have a new scale and rivets. I'll do a before and after.
That seems like a lot to be off.

MichaelB said:

Inner chaincase rocks, glad I got some shims. Install screws to check clearance, Now it's fine with the stock spacer.

Click to expand...

When I installed a new inner, the hole that that slipped over the engine crankcase was slightly small and slightly out of round. I could have forced it on, but I carefully blued, tested, and sanded until it just slipped on - no rocking. Put in the screws temporarily and checked the center stud. Loosened it and move it until centered in the cover hole. Then used feeler gauges to determined the correct shims between the stud and cover.

Check clearance @ .008 with brass (non magnetic) feeler gauge.
It's tight on the bottom. Spin it around, check again, Consistently tight on bottom.
F#&^%*(...... Stare at it for awhile, thumb through manual. Manual says to bend the studs. Been there, done that, don't want to.

Click to expand...

Don't bend, loosen the nuts and recheck. Can be wrong because the spacers are slightly different lengths. Failing that, it's possible to open the stator holes SLIGHTLY and get it right. Sometimes, it's only one hole a little out of line.

One question, what is the proper placement of the rotor in the stator.
I just reused the original shims, looks like it could come out some more.
Is there a magical placement?

Click to expand...

Other British bikes have the rotor more or less centered in the stator. The Norton can't due to the timing marks. Looks very wrong on a Norton, but works just fine.

Just notice there are there are two timing scales available.
06.0736 Pre Mk 3, fixed with rivets.
06.4694 Mk 3, adjustable with screws with V-cut at 28.

Will a Mk 3 scale work with a Pre Mk 3 cover?
Anyone ever do this?