Triumphrat

GulfCoastDave · 07-22-2006, 12:34 PM

So now as I push on trying to get the '79 ready to ship... I take down the clutch side to prepare for Haywood belt drive and what do I find? The stator is rubbing against the rotor! Not a lot... and I can't actually feel any juggle in the crank... but there it is. And of course I had been having the ignition problem... perhaps caused by failing stator (although one coil was bad).
In my experience, the inescapable conclusion is that the main bearing (s) need to be replaced. Can anyone offer anything to the contrary?

If that job is necessary, I will turn back to the '78 and begin taking down the transmission (shudder!) to try to find the origin of the "clanging" noise going into third.
Thanks in advance,
GCoastDave

panda · 07-22-2006, 01:54 PM

First, it will be the rotor that is rubbing on the stator, not the other way round, unless you have 'real ' problems.

things to check, make sure rotor is close fit to crankshaft with the nut loose. make sure nut is tight.
remove the stator and check the holding studs not bent, is likely that a previous problem has set the stator off centre.

if these all ok, and the rotor spins with no runout... it just maybe the crankshaft bearing. these are not difficult or expensive to change, but it will take quite a few man hours. it is just a matter of attrition.

good luck

GrandPaulZ · 07-22-2006, 04:27 PM

An overheated stator can expand in size, usually accomanied by some unmistakable smell of burnt potting compound and internal windings.

Typically you get blistering and de-lamination as well.

Dead shorts ahead of the fuse, and no fuses in the system can cause problems like that.

GulfCoastDave · 07-23-2006, 08:30 AM

Panda... right... of course it is the rotor rubbing on the stator... not the other way around.
The rotor was not loose & the stator was not off-center.
Replacing main bearings an easy job? By my book, it means stripping the entire motor... trans, crank & all.

GPZ... looks like you hit it... there is blistering all right some small bubbles on the outer face... and there were electrical issues going on prior. The rubbing was at the outer portion of the perimeter and was even all the way around... which made me suspect the bearing... but... I can't feel any play in the crank (doesn't really rule that out though). Is it possible that the bearing IS bad and that the rotor hitting the stator then screwed up the stator ...causing it to overheat? Reversing cause & effect.

I guess it will be best to assume that it's a short... replace the stator... put it back together & find the short.

Meanwhile... I've already started stripping the transmission on my '78... so I guess I'll move forward with that.
Thanks Guys,
GCoastDave

panda · 07-23-2006, 02:36 PM

[quote]
On 2006-07-23 07:30, GulfCoastDave wrote:
Panda... right... of course it is the rotor rubbing on the stator... not the other way around.
The rotor was not loose & the stator was not off-center.
Replacing main bearings an easy job? By my book, it means stripping the entire motor... trans, crank & all.

G/quote]

Not sure about the 750, but on the 500's it is possible to split the crankcases without disturbing the gearbox, have to dismantle primary side though. I said it was not difficult, just a lot of work.. if you see what i mean... But I ma sure GP has put you on the right track.