New stator melted in 20 miles

annajeannette said:
hello all stators should be set all way round at 8 thou not 6 thou that,s why you did some cooking
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Actually .008 not .006 but, I didn't rotate the engine and the rotor doesn't seem to be perfectly concentric. Another possibility is that with a shorting RR and engine/oil heat the stator was actually expanding reducing the clearance.

I have to replace the primary gasket as the Real Gasket reusable has given it up in one spot. I'll get a look at the stator then. I don't expect to see any sign of heat distress.
 
JimNH,
How about a picture of where you ended up mounting your Shindengen unit?
Thanks,Mike
 
annajeannette said:
hello all stators should be set all way round at 8 thou not 6 thou that,s why you did some cooking
Click to expand...
Hello! Try 10 thou. 6 is definitely not enough!
...and use 10 thou shim stock in at least 3 equally spaced places whilst tightening the stator.
If you can't get 10 thou in then something needs skimming (unlikely)
Cheers
 
robs ss said:
Hello! Try 10 thou. 6 is definitely not enough!
...and use 10 thou shim stock in at least 3 equally spaced places whilst tightening the stator.
If you can't get 10 thou in then something needs skimming (unlikely)
Cheers
Click to expand...
New one has been in for a while now with a minimum of 10. Since the Real Gasket reusable was questionable in one spot I'll have to replace it. I've got a couple a couple of paper gaskets on the shelf but I was determined to get my money's worth out of the Real Gasket. BTW, I don't recommend them as after the first use they become so floppy that I've had to use lacing cord to secure in place through the bolt holes then cut the cord once bolts started. They have to be installed perfectly dry and oil free, no gasket cement.
Anyway, I'll examine the stator at that time and expect it to be perfect.
 
A friend just had a stator melt on a Commando he bought in the UK.

And after reading this thread I decided I would check my bike which had a new lucas stator and rotor installed 6 years ago. Bike had run maybe 600 km since then with few rides longer than 80 km.

I measured the clearance at a minimum of a tight 8 thou with variation up to 9 or ten.

When I took it off I could see signs of very mild contact.

The rotor was dialed up on centres and found to be about 1 thou eccentric. My engineer dressed it with a ceramic tool and it took around 4 thou cut to dress the rotor perfectly round across all the surface. Took off 6 in total to give 14 thou clearance. He had done several before and found no loss in charging up to the 15 thou clearance he has tested.

On the strength of this and experience of others recorded in this thread I recomend anyone fitting a new rotor should check carefully and have it skimmed if necessary. Many / most / all supplied today are a bit oversized
 
I am convinced that modern parts manufacturers are making these things with a gap that’s just too tight. Probably coz they don’t understand how flexy these old lumps are?

I have had one rub even with a confirmed 10 thou gap.

I now have the rotor turned down to ensure a 20 thou gap (ie 40: thou smaller than the stator ID) and this seems to do the trick.

Our milk cartons are just thick enough to insert as shown and ensure nothing closes up when tightening etc.

IMG_1154.jpeg
 
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Update:

Well, I still haven't found time to pull the primary off and decided to wait 'till winter to put it on the lift and attend to it, some leaks, fork seal, etc. What I can report is the SH847 and a new stator seem to work perfectly. I've just ordered a Gerbing heated vest so I'll see how it handles the load.
 
Hi Jim, I have a similar set up, but regulator is from a Harley, same type as the SH847. LEDs everywhere and no problems. 4000 miles so far. Graham
 
Fast Eddie said:
I am convinced that modern parts manufacturers are making these things with a gap that’s just too tight. Probably coz they don’t understand how flexy these old lumps are?

I have had one rub even with a confirmed 10 thou gap.

I now have the rotor turned down to ensure a 20 thou gap (ie 40: thou smaller than the stator ID) and this seems to do the trick.

Our milk cartons are just thick enough to insert as shown and ensure nothing closes up when tightening etc.

View attachment 121560
Click to expand...
Full fat, or semi skimmed?
 
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