What Did You Do With Your Commando Today?

[Andy Higham]

He is called Dio

 

[nortonmargie]

Today I: checked head bolts, looks like the composite gasket has finally settled in, checked valves, clearances good, checked primary and gearbox oil, both levels OK. I replaced one exhaust valve gasket and the intake gasket with the JS Motosports silicone fiberglass gaskets. Decided not to replace the other exhaust valve gasket yet, because the paper gasket looks good and I want to do a test run on the fiberglass.
I replaced the head and tail light with LED's. The headlight is from Paul Goff, tail light is Lucas. The first photos is the LED headlight. The second photo is the old taillight. Photo 3 is the LED taillight. Photo 4 is the previous headlight, a 60 watt H4

 

[King Of Cryo]

So, what happened with your bike to make it quit like that? Was there a problem with your new stator? I'm going to be doing the same thing soon and upgrading my original alternator setup with a 3-phase kit from Matt @cNw.

Ha! I was out of gas. My last stator (3ph 10.5a) was rubbing on the rotor. It melted the epoxy and destroyed the whole thing. I took a cue from Matt and modified the new stator to increase clearance. It still charges at perfect levels.

 

[Fast Eddie]

Ha! I was out of gas. My last stator (3ph 10.5a) was rubbing on the rotor. It melted the epoxy and destroyed the whole thing. I took a cue from Matt and modified the new stator to increase clearance. It still charges at perfect levels.

What was Matt’s trick for increasing clearance ?

 

[HouTexNorton]

Ha! I was out of gas. My last stator (3ph 10.5a) was rubbing on the rotor. It melted the epoxy and destroyed the whole thing. I took a cue from Matt and modified the new stator to increase clearance. It still charges at perfect levels.

Many seem to have this problem (at least that talk about it). When I bought my 14.5 amp 3 phase stator with a new rotor from Matt I used a cut-up plastic water bottle that measured 0.01" thick to make sure I had the proper clearance between the rotor and stator (I have Matt's e-start so the stator mounting is different than stock). I tested it at idle and the clearance and charging was fine. I went for a ride and noticed that my IC charge warning light was showing no charging after a while. When I got back home and pulled the stator it was completely melted and destroyed. I had Matt turn down the rotor 0.01" all around and installed a new stator. Same installation procedure with no issue at idle, but when ridden it was rubbing again, but not as much. I used a Dremel tool with a sanding drum to clean up the inside of the stator and remove a little of the epoxy material all around being careful not to damage the magnets. Finally all is well, but I would guess that I now have about 0.025" of clearance and still get good charging. I measured the crankshaft with a dial indicator and am not getting any noticeable deflection when manually turning it, but who knows if there might be some when it runs and heats up. Maybe a slight bearing issue, although the engine has less than 1,000 miles since completely rebuilt by Classic Bike Experience.

 

[Fast Eddie]

Many seem to have this problem (at least that talk about it). When I bought my 14.5 amp 3 phase stator with a new rotor from Matt I used a cut-up plastic water bottle that measured 0.01" thick to make sure I had the proper clearance between the rotor and stator (I have Matt's e-start so the stator mounting is different than stock). I tested it at idle and the clearance and charging was fine. I went for a ride and noticed that my IC charge warning light was showing no charging after a while. When I got back home and pulled the stator it was completely melted and destroyed. I had Matt turn down the rotor 0.01" all around and installed a new stator. Same installation procedure with no issue at idle, but when ridden it was rubbing again, but not as much. I used a Dremel tool with a sanding drum to clean up the inside of the stator and remove a little of the epoxy material all around being careful not to damage the magnets. Finally all is well, but I would guess that I now have about 0.025" of clearance and still get good charging. I measured the crankshaft with a dial indicator and am not getting any noticeable deflection when manually turning it, but who knows if there might be some when it runs and heats up. Maybe a slight bearing issue, although the engine has less than 1,000 miles since completely rebuilt by Classic Bike Experience.

On all my Lucas equipped Brit bikes I now ensure a 0.020” gap (ie rotor OD 0.040” smaller than stator ID) and use a strip of a plastic milk carton to ensure clearance all round when tightening things up.
I’ve never had any charging issues as a result.
Someone on here cleverer than me once calculated the likely reduction in charging as a result and it was practically unmeasurably small.

 

[nortonmargie]

Many seem to have this problem (at least that talk about it). When I bought my 14.5 amp 3 phase stator with a new rotor from Matt I used a cut-up plastic water bottle that measured 0.01" thick to make sure I had the proper clearance between the rotor and stator (I have Matt's e-start so the stator mounting is different than stock). I tested it at idle and the clearance and charging was fine. I went for a ride and noticed that my IC charge warning light was showing no charging after a while. When I got back home and pulled the stator it was completely melted and destroyed. I had Matt turn down the rotor 0.01" all around and installed a new stator. Same installation procedure with no issue at idle, but when ridden it was rubbing again, but not as much. I used a Dremel tool with a sanding drum to clean up the inside of the stator and remove a little of the epoxy material all around being careful not to damage the magnets. Finally all is well, but I would guess that I now have about 0.025" of clearance and still get good charging. I measured the crankshaft with a dial indicator and am not getting any noticeable deflection when manually turning it, but who knows if there might be some when it runs and heats up. Maybe a slight bearing issue, although the engine has less than 1,000 miles since completely rebuilt by Classic Bike Experience.

I had the same problem with a rotor bought from Andover. I spent several days with sandpaper and feeler gauges, making sure I had clearance all around. I found that there was a very slight wobble which led to less clearance in some positions.

 

[nortonmargie]

Went for 75 mile ride, breakfast and back. Bike ran fine. Came back and changed oil and filter. I usually spill a lot of oil doing oil changes and this time I just spilled a few drops. Happy camper.

 

[ludwig]

Wow!! That’s built to last!

It takes up to 2 hrs . of sanding down circularly on a flat plane to get the snug fit .
Finger tips should be protected

Not if you use this :

 

[YING]

Many seem to have this problem (at least that talk about it). When I bought my 14.5 amp 3 phase stator with a new rotor from Matt I used a cut-up plastic water bottle that measured 0.01" thick to make sure I had the proper clearance between the rotor and stator (I have Matt's e-start so the stator mounting is different than stock). I tested it at idle and the clearance and charging was fine. I went for a ride and noticed that my IC charge warning light was showing no charging after a while. When I got back home and pulled the stator it was completely melted and destroyed. I had Matt turn down the rotor 0.01" all around and installed a new stator. Same installation procedure with no issue at idle, but when ridden it was rubbing again, but not as much. I used a Dremel tool with a sanding drum to clean up the inside of the stator and remove a little of the epoxy material all around being careful not to damage the magnets. Finally all is well, but I would guess that I now have about 0.025" of clearance and still get good charging. I measured the crankshaft with a dial indicator and am not getting any noticeable deflection when manually turning it, but who knows if there might be some when it runs and heats up. Maybe a slight bearing issue, although the engine has less than 1,000 miles since completely rebuilt by Classic Bike Experience.

You are fortunate. I have melted 2 stators in the last week! I had .013 minimum clearance at ALL positions on the rotor.Started bike,checked charge rate,all good,went for 10 mile ride,came home and removed primary cover and re-checked the clearance.Everything good.Then went out for 50 miles or so and removed cover again to see another melted stator.This whole process has happened twice now and I have absolutely no idea of what is going on. I went over every check on my install along with a new regulator/rectifer to see if that was my grief. I am at wits end on this as they don’t give those stators away.No noticeable run-out on the crank.Any suggestions??
Mike
Same set-up as HouTex

 

[Fast Eddie]

You are fortunate. I have melted 2 stators in the last week! I had .013 minimum clearance at ALL positions on the rotor.Started bike,checked charge rate,all good,went for 10 mile ride,came home and removed primary cover and re-checked the clearance.Everything good.Then went out for 50 miles or so and removed cover again to see another melted stator.This whole process has happened twice now and I have absolutely no idea of what is going on. I went over every check on my install along with a new regulator/rectifer to see if that was my grief. I am at wits end on this as they don’t give those stators away.No noticeable run-out on the crank.Any suggestions??
Mike
Same set-up as HouTex

Well (obviously) my first suggestion would be to increase your gap to .020.

But are you sure it’s rubbing? Or is it doing what Grant Tiller talks about lot about?

 

[robs ss]

Well (obviously) my first suggestion would be to increase your gap to .020.

But are you sure it’s rubbing? Or is it doing what Grant Tiller talks about lot about?

Are you talking about rectifiers doing something silly and shorting things under certain circumstances?
If that's the case then it could be verified by setting up the new stator, but not connecting it up to the regulator.
Have a fully charged battery and go for the same 50 mile trip (daytime and minimise light use). If all's good, then what you say about Grant Tiller's findings may be the case.
Cheers

 

[King Of Cryo]

What was Matt’s trick for increasing clearance ?

His stators are smoothed back a bit in the middle core and around the fixing holes. I actually filed and sanded mine back a fair amount. I also widened 2 of the stator mounting holes to allow a bit of a pivot on the 3rd stud.

 

[Fast Eddie]

Are you talking about rectifiers doing something silly and shorting things under certain circumstances?
If that's the case then it could be verified by setting up the new stator, but not connecting it up to the regulator.
Have a fully charged battery and go for the same 50 mile trip (daytime and minimise light use). If all's good, then what you say about Grant Tiller's findings may be the case.
Cheers

I can’t recall all the details now, but Grant basically believes that the modern trend to fit high powered stators and low energy LED bulbs etc leaves the stock system unable to handle the power and heat.

Hence the use of shunt type regulator units like the Shindengen.

And as much as I’m a fan of belt drives, a dry primary also deprives the area of some oil cooling, and perhaps even lubrication in the event of some mild rubbing. Neither of these is a root cause, but possibly contributory factors to the above heat issue.

Then add tighter than needed clearances into the mix and maybe it’s all just too much, even though there’s nothing actually ‘wrong’ or faulty.

 

[Nortoniggy]

You are fortunate. I have melted 2 stators in the last week! I had .013 minimum clearance at ALL positions on the rotor.Started bike,checked charge rate,all good,went for 10 mile ride,came home and removed primary cover and re-checked the clearance.Everything good.Then went out for 50 miles or so and removed cover again to see another melted stator.This whole process has happened twice now and I have absolutely no idea of what is going on. I went over every check on my install along with a new regulator/rectifer to see if that was my grief. I am at wits end on this as they don’t give those stators away.No noticeable run-out on the crank.Any suggestions??
Mike
Same set-up as HouTex

You could have a problem with the inner primary chaincase alignment changing when you put the outer cover on. Try this, check clearance on stator, then use a spacer on the centre stud and tighten the nut that secures the outer cover as if cover was fitted. Check the stator clearance again. If it has changed you don't have correct amount of shims behind inner chaincase and it's distorting when you fit outer cover.

 

[YING]

You could have a problem with the inner primary chaincase alignment changing when you put the outer cover on. Try this, check clearance on stator, then use a spacer on the centre stud and tighten the nut that secures the outer cover as if cover was fitted. Check the stator clearance again. If it has changed you don't have correct amount of shims behind inner chaincase and it's distorting when you fit outer cover.

Iggy
I was very careful when setting up the shims on the center stud when I last had it apart but will check it again first thing today.Good idea on that which I would never have thought of.Center nut was never over tightened but who knows.Also I have LED bulbs everywhere thinking that was the way to go for being easier on the charging system.At this point any suggestions are appreciated.
Mike

 

[robs ss]

Iggy
I was very careful when setting up the shims on the center stud when I last had it apart but will check it again first thing today.Good idea on that which I would never have thought of.Center nut was never over tightened but who knows.Also I have LED bulbs everywhere thinking that was the way to go for being easier on the charging system.At this point any suggestions are appreciated.
Mike

Mike, if rubbing between the stator & rotor is the issue surely there would be witness marks on the steel parts to prove that?
It would help to identify if you're chasing a mechanical or electrical problem.
Cheers

 

[velo54]

Ying, using a 14.5 amp stator with LEDs and a short or shunt type voltage regulator, is a recipe for burnt out stator. The system will put out way more power than necessary, and is way out of balance. Read and understand Grant Tillers article on voltage regulators. Even Trispark no longer sell the high power stators because of come backs, even using his Mosfett regulator. I am using a 14.5 amp stator with LEDs and an open type regulator from a Harley and no problems. Just finding a place to mount the huge regulator is the worst problem. Graham

 

[B+Bogus]

Mike, if rubbing between the stator & rotor is the issue surely there would be witness marks on the steel parts to prove that?
It would help to identify if you're chasing a mechanical or electrical problem.
Cheers

This is the question


Another question is which stators are failing? Old original Lucas or modern Lucas? 2 or 3 phase?
Is it metal to metal contact, or potting resin expanding and grabbing the rotor?

I just measured an original stator and the ID was 2.96" between pole pairs
A new Lucas 2 phase 16A stator ID is 2.950" between pole pairs
A new Lucas 3 phase 14.5A stator being 3 phase I can't measure across poles, so allowing for the resin being set back I'm guessing it's near 2.95"

 

[HouTexNorton]

I will add that I also have all LED lighting, a Tri-spark voltage regulator, and a cNw e-start. The last stator that I installed I went back to a 10.5 A single phase and I've had no issues starting the bike--maybe this is why I finally resolved my stator melting issue? Could I have been overheating the system with the 14.5 A 3 phase stators that were melting?