Alton Makes Good...really fast!

I wanted to post this as a new thread because I want everyone to have a better chance of seeing it as opposed to only those currently interested in my Alton alternator issue (disintegrated).

As I posted in my other thread - viewtopic.php?f=1&t=15136, on Dec 22, my newly installed Alton Estart alternator came apart. I sent a message to Norvil, where I purchased it and then later sent one directly to Alton. I had assumed that since it was purchased from Norvil, they would be the ones to deal with the issue. My message to Alton was more of an afterthought.

I received a response back from Alton in less than an hour. We exchanged a couple of additional emails with specifics and this morning (Dec 24) had an email from Alton stating that the replacement parts have been shipped to the business address here in Mexico at no charge. IMO, as far as covering their products, this puts Alton up there at the very top of the heap and from that aspect would heartily recommend them to everyone.

As to what actually happened to the alternator, that's unknown. Paul said that what happened is typically caused by a alternator/stator clearance problem but I had described what I did and he agreed that the clearance was set correctly. One thing occurs to me...Just before the warning light illuminated I had run the bike aggressively through the gears, hitting the 7k max RPM a couple of times (Yes, I know that the 850 doesn't make additional HP beyond around 6 but I have spun it to 7 in first/second on a few occasions and the engine hasn't objected). Shortly after that the charge warning light came on which is when (I assume) the magnet portion of the alternator let go.

I'm wondering if it's possible that there is sufficient crankshaft flex at that RPM to cause the rotor to hit the stator. This is just a WAG on my part but aren't commando motors known for crankshaft flex which was the reason the combat bearings didn't hold up? Of course one would expect the stock rotor to exhibit the same problem under the same conditions but the Lucas rotor is of considerably smaller diameter and the inner diameter of the lucas stator is smooth so maybe an occasional flex/rub doesn't really have any effect. My Lucas rotor did have some rub marks - not grooves just shiny rub marks and it's clearance was set very carefully several times over the past 6 years during various projects. IOW, the Alton rotor may be perfectly OK with the RPM involved but if it does contact the stator coils, given the design of the rotor/stator, there could be a higher chance of damage. Again, this is TOTALLY speculation on my part. I have NO idea if crank flex could be an issue here. But when I reinstall the new rotor, I will keep the RPM to "normal" 850 peak levels, not the 7k listed as max for the 750 and 850 engine.

But back to my original point - my strongest possible kudos to Alton (Paul and Beverley) for their immediate response, concern, and coverage of their products.

Haven't heard a word from Norvil but I'll give them the benefit of the doubt since it's the holiday season...

Here's to making things right, the only way to do it.

Very Good!

My guess is that the flex would cause it. Why you rev it that hard is the mystery. :mrgreen:

"Why you rev it that hard is the mystery. "

Trying to pretend that it's still the superbike it once was. But I have never exceeded the factory specified max RPM and have only hit that on occasion at a shift point, not sustained in any gear. However, I readily admit I do run it pretty hard. If I wanted to just putt around I'd get a Harley.

But as I said, I won't hit 7k anymore, on the chance that crank flex was the cause. It would be nice to know for sure that crank flex is an issue in this case but I don't know any way to determine it with any equipment I have available.

I think your assumptions are reasonable. We know the cranks flex. The increased diameter of the Alton alternator could the be issue. They may need to rethink the clearances. Surprised this didn't show up in their testing, I'm sure they revved it up that far.

I doubt that crankshaft flex or rubbing had anything to do with your failure although revving it that hard would put the test to the integrity of the rotor. It should be designed to handle that rpm with a margin.

The crank in my 880 is stock with a nodular center weight. The injection rev limiter is set at 7600 and I seldom ride the bike without bouncing it off the rev limit at least a couple times. I have used blue on my external rotor to see if their is contact and it has not been a problem. Jim

comnoz said:

...I seldom ride the bike without bouncing it off the rev limit at least a couple times.

Click to expand...

He he he. My hero.

mike996 said:

I'm wondering if it's possible that there is sufficient crankshaft flex at that RPM to cause the rotor to hit the stator....

Click to expand...

Did you check the primary shaft itself for trueness with a micrometer?

"Did you check the primary shaft itself for trueness with a micrometer?"

No I did not. I checked the rotor/stator clearance multiple times and rotated the crankshaft by hand so although that's not precise compared to measuring runout with a dial indicator, it did tell me that there was no meaningful variation in the clearance, at least when the engine was NOT running. It didn't occur to me to check it since it had never been an issue before...and maybe isn't now.

"...I seldom ride the bike without bouncing it off the rev limit at least a couple times"

And that's the way I ride my much lower powered bike except I don't actually have a rev limiter to bounce off of!

I love to hear of Commandos doing what they were made for, which in 850 case was mainly touring duty.

Setting clearance by shim is even better than checking crank end run out for the life of the Alton. But that is just static perfection. Those shiny witness areas on your rotor are indeed evidence of crank jump roping so ends tip oppositely and collides with the stator laminations, which should also be inspected. Don't know how close JIm has inspected his alternator or replaced with a fuel cell but Peel showed the arch the Lucas rotor wiped inside of stator, about 7:30 to 4:30. If just holding throttle to 7000 and easing off was done then maybe ok but snapping throttle shut at that rpm would help suck piston to the roof on top their jerk down inertia to bow crank so ends tip in the giving superblends. Anywho if was me I'd creep up on next install red line by say layers of tape or thick witness material on some the coil ends and see when it starts to get wiped off and take notes for the rest of us learning the easy way.

Its tricky to glue magnets down as pure adhesions just dont do it long or fast. Needs some type over lapped lips/scratches so that mainly its the shear strength of the epoxy is loaded. Most Epoxy softens up after boiling temps, even hi temp JBW.



I

Glue is for models and then they fall to bits sooner or later.

Glue is great for keeping the magnets from wiggling and wearing out the metal parts that actually hold them together.

Hobot,
I use an external rotor alternator on my bike. It has similar clearance to a Lucas alternator. I have painted the ID of the rotor with spray on blue and it has been untouched every time I have pulled it off. I would suspect it is still there looking just like it did a year ago when I pulled it for a look. Jim

It seems clear to me, in looking carefully at the rotor's magnet retainer, that it must have contacted the stator coil poles. The retainer separated almost exactly in the center of its circumference all the way around. Though not as smooth, it appears as it would if the rotor was spinning and you placed a cutting tool in the center of the circumference, parting it in the center. So since there was plenty of rotor/stator clearance in all positions with the engine not running, crankshaft flex at RPM is the only thing I can come up with that could have caused it.

When I get the new parts I'll put a dial indicator on the crankshaft at the rotor end and try to see how much up-down or left-right motion I can induce in the crank by levering it in those directions. Obviously if I can induce the equivalent (or more) of the clearance spec for the rotor/stator, then I'd say the bottom end has to have new bearings in order to safely run the Alton - or at least to run the bike at max RPM, which is admittedly not necessary. Clearly, whatever play is there has no adverse affect on the Lucas RM 24.

"Anywho if was me I'd creep up on next install red line by say layers of tape or thick witness material on some the coil ends and see when it starts to get wiped off and take notes for the rest of us learning the easy way. "

This sounds like a good idea and that's what I might do...

My wife's suggestion re all this earlier today at "Christmas Eve" dinner was: "Why don't you just buy a new Ducati?"

comnoz said:

Glue is great for keeping the magnets from wiggling and wearing out the metal parts that actually hold them together.

Hobot,
I use an external rotor alternator on my bike. It has similar clearance to a Lucas alternator. I have painted the ID of the rotor with spray on blue and it has been untouched every time I have pulled it off. I would suspect it is still there looking just like it did a year ago when I pulled it for a look. Jim

Click to expand...

But what diameter is it? Also the weight of the Lucas rotor may dampen some of the crank flex, I wonder if the Alton rotor is lighter?

If it were actually flex that caused the retainer to touch the pole pieces then I would only expect to see damage on one side of the rotor.

If the retainer grew in diameter from centrifugal force then it would make contact all the way around.

If the bearing had axial play it would cause contact all the way around but it would be pretty noisy. A few thou axial play in a main bearing makes a knock that is hard to miss. Jim

External? As in outside case or not directly on crank end? Anyway we are grassing at straws why this instant case lost magnets so my long distance suggestions. I don't get rotor/stator fouling in my stock Combat nor hotted up to take it Combat Peel well into red zone - until way beyond rpm the tach could register or regular Combat survive at all. Now if a Commando was made to be a pussy cat to kick over there'd be no need of wimpy alternator with wimpy exposed edge magnets to fit a starter. Peel will have 600 watt juicer to help all weather operation and other gizmos and tiny battery topped off.

I've studied the windpower guys DIY alternators and been into lawnmower style and have little faith in glue or epoxy to hold magnets once heated and spun up.

This is only way adhesives have half a change to retain magnets

Out of curiosity,
what is the rotor / stator clearance measurement for the Alton?

comnoz said:

If the retainer grew in diameter from centrifugal force then it would make contact all the way around.

Click to expand...

That's what I was thinking.

The RM24 Lucas rotor is 2 7/8" in diameter; the Alton is 4 1/8" I don't have a scale here - holding each in the hand I can't tell any difference. But the "hand scale" is not very precise...

Jim, good point re the "cutting action," I hadn't thought about that - if due to flex it would occur at the same point on the rotor each time, not like a lathe/cutting tool all the way around. Expanding due to centrifigual force...maybe so. I'll post some close up pics of some of this in the next day or two. I'll also be sending them to Paul at Alton, followed by the actual parts to him after the holiday period.

The clearance is .4mm per Alton and they supply plastic shim material for this purpose.