G15. Regrind the rotor

New RM 21 stator and his stock used rotor.
Coloured in blue the rotor faces and
fitted the outer primary chaincase with the stator into.
A lot of kick start to rotate engine.
Removed the primary chaincase.
The six stator coils was all blue colored.
Regrinded “1 decimo” the rotor (well cleaned from colour) and checked again with same way.
The six stator coils was coloured again.
Regrinded the stator another “1 decimo” more.
Checked again and the stator was completely cleaned; it didnt touch the rotor more.
May be is not very correct to regrind the rotor, may be the recharge will be not very strong, but i will drive quite and safe.
Ciao
Piero

I am surprised all six stator were coloured. If there was a clearance issue all way around, you would't be able to fit the outer primary cover.
Was the stator properly tightened? Or could it be that your crankshaft displays a warpage (i.e., shaft makes an oval motion during one turn)?
I guess "1 decimo" is 0.1mm ? So you shaved the rotor for 0.2mm . There is another thread here discussing the effect of gap between the magnets and the coils.

-Knut

mdt-son said:

I am surprised all six stator were coloured. If there was a clearance issue all way around, you would't be able to fit the outer primary cover.
Was the stator properly tightened? Or could it be that your crankshaft displays a warpage (i.e., shaft makes an oval motion during one turn)?
I guess "1 decimo" is 0.1mm ? So you shaved the rotor for 0.2mm . There is another thread here discussing the effect of gap between the magnets and the coils.

-Knut

Click to expand...

Yes.
0,2 mm shaved.
Shaft rotate without eccentric movement and rotor lock nut was well tighten.
0,2 mm and i will drive safe and happy.
Ciao
Piero

pierodn said:

Shaft rotate without eccentric movement and rotor lock nut was well tighten.

Click to expand...

I don't question the rotor lock nut, the stator nuts however. Your finding is even more surprising if you dialed the shaft and the rotor prior to assembly.
Obviously some of the components displaced .... and you should double check. Shaving the rotor will not help if the fault isn't lack of clearance.

-Knut

S

mdt-son said:

I don't question the rotor lock nut, the stator nuts however. Your finding is even more surprising if you dialed the shaft and the rotor prior to assembly.
Obviously some of the components displaced .... and you should double check. Shaving the rotor will not help if the fault isn't lack of clearance.

-Knut

Click to expand...

Sorry.
I dont understand what you mean for “Your finding is even more surprising if you dialed the shaft and the rotor prior to assembly.”
and “Your finding is even more surprising if you dialed the shaft and the rotor prior to assembly.”.
Let me understand.
Piero

The stock rotor and the new RM stator matched prior to assembly, didn't they? I mean, there was a certain clearance between them?
According to you the crankshaft (and therefore, the rotor) didn't show any eccentricity.
One thought though: The old rotor is probably not of the welded type. They have a habit of "growing" radially and in the end, they "explode" as the magnets let go.
Therefore, I would examine the rotor carefully before giving it the green light, Beyond all, please ensure it is of the welded type.

Now, if your rotor gets the green light, the proper way of adjusting the clearance is by forcing the stator to move relative to the rotor using suitable spacers on the rotor and semi-loose stud nuts. After a few trials the stator stud nuts need to be securily tightened. Was your stator studs properly tightened? If not, the stator would move around and the rotor high spot would touch all the coils.
However, If your stator stud nuts were tightened and the stator wasn't completely centred on the rotor, the marking colour would smear on some of the coils only, but not all of them.

This lets me think there was a clearance issue between rotor and stator from the outset.

-Knut