alternator stator rivets

[Parker3865]

So I started my bike after an oil change and not having run it for a few weeks. I was greeted by a squeaking/graunchy noise at low revs coming from the alternator cover. So off with the cover, off with the flywheel and wriggle the stator coils. Oh dear there seems to be some play! So off with the stator and it seems the long rivets that hold the coil laminations to the aluminium stator plate are ever so slightly loose. Must be enough to rattle/rub against the flywheel, although I could see no witness marks. So bodge a rivet stake to place them against and thwack them with a hammer and punch. Now tightened up, re-assembled and quiet again. Any guesses how long this repair will last OR will i be needing a new (to me) stator?

[Ming]

You can replace the rivets with new ones, or with screws - but if you use screws ensure that the heads / nuts don’t protrude enough to rub on the rotor. Also use loctite on the nuts. - this from personal experience.

[Parker3865]

Thanks for the advice.

p.s. one of the holes for the m6 screws attaching the stator is nearly stripped. Screw currently just nipped up and a dab of locktite for good measure. Apart from rereading Julian's post about stripped spark plug threads, any suggestions?

[Steve Brown]

An M6 helicoil kit is what you need here. (Helicoil is a brand name trademark but these days you can get kits from many firms that work exactly the same. Recoil and Uni-Thread are 2 brands I've used. A single kit won't break the bank and there are 6mm threads all over the Morinis and every other bike that is metric, so it won't be wasted.

[mbmm350s]

Plus 1 for the helicoil.
If you havent come across a stripped rocker cover screw or a rocker stud or generator cover screw etc etc then you will some day. A right angle drill is a great investment too.
Mark

[Parker3865]

Thanks, have a right angled drill, never used it though.

[Parker3865]

Update:
So rivets loose again. Some axial play but not touchIng the flywheel (that I can see). I wonder if it is more crash damage?

1) will be investigating new rivets: anybody know what size I need?

2) is a loose stator enough to make the engine run horribly? Mis-fires above 5500 and will not tickover? If not I gave other problems, oh dear!

[Steve Brown]

Interested to hear how you do fix it when it's done. I have a spare stator in a similar condition-haven't needed it yet!
As for the running problems, I think it would likely upset the earthing of the ignition coil to the back plate and crankcase. It might well behave like a coil that is breaking down (open circuit)
The earlier suggestions of screws with the heads trimmed for clearance must be worth investigating?

[Parker3865]

Interested to hear how you do fix it when it's done. I have a spare stator in a similar condition-haven't needed it yet!
As for the running problems, I think it would likely upset the earthing of the ignition coil to the back plate and crankcase. It might well behave like a coil that is breaking down (open circuit)
The earlier suggestions of screws with the heads trimmed for clearance must be worth investigating?

Upset earthing would explain why it has got progressively worse as I ran the engine.....you know you should stop and investigate BUT you want to get home!
May look at screws and nuts? Thanks Steve.