Sparx alternator catastrophic failure

I recently had a complete failure of the Sparx 3-phase alternator in my MK3. I believe this may have been one of the bad batch Sparx produced about 3 or 4 years ago.
Here is how it looked when I acquired the bike 18 months ago, as far as I'm aware the PO never ran the bike - I bought it without a wiring harness, so believe it.


I ran the bike for about 500 miles with no problems, then the charging light would glow below 2000rpm. After another 100 or so miles the light was bright up to about 2800rpm.

I tested the alternator with a bulb and it tested ok.

Next time I took the bike out the charge light was lit constantly and I almost made it back home (funny how that happens) before the battery died.











There was no scoring in the center, so it wasn't caused by the rotor rubbing. My guess is that this batch was wound incorrectly and that caused it to overheat and self destruct.

I cleaned up blobs of potting from inside the primary and fitted a new Wassell alternator, checked the clearance - between .008 and .010 gap all the way around. Now I'm getting a good output at 1100rpm, warning light goes out on start and no glow in the warning light at all at idle.

Let's see how long this one lasts.

Sounds like a warning for S. purchasers. A buddy noticed the same symptoms . We opened up the primary cover on a country roadride and there was an atom bomb of white smoke. He made it home with the primary cover bungee corded to the passenger seat , after we picked away all the burnt up stator bits.

Yikes.

I have one in my Combat, but it doesn't get ridden much, and never at night.

I've sold 2 or 3 of those over the years, haven't heard of a failure yet (nor on the single-phase ones).

I'll bet if you can track back to where it was sourced, they'll get Sparx to replace it. They are EXCELLENT at warranty, and even non-warranty when justified (as this would be)

Had one self destruct on my Norton...not quite that dramatic but dead just the same. Put a stock single phase Lucas back on and have had no troubles.

Damn!
I wanted to install one of these Sparx units in my MK3 this winter.
I thought these problems were confined to dry primaries with belt drives.
This really gives me pause.

MikeG said:

Had one self destruct on my Norton...not quite that dramatic but dead just the same. Put a stock single phase Lucas back on and have had no troubles.

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I had one in my 58 Domie 88 years ago. Took it to Colorado shortly after I had installed it. It quit working about 50 miles from the campground but I was able to get it back before the battery died. The rotor had lost its magnetism! I had gotten it from AMR who had gotten it from JRC. They sent a new rotor no questions asked just wanted the old rotor.
John in Texas

Hmmm? Feeling a little concerned. I have a 9 year old 3 phase Sparx that seemed to be showing some of the same symptoms before I put the bike away for the winter. Might have to tear into it and have a look when I get a chance. I have a couple of spare lucas single phases lying around but no idea what rating they are. Is there any way to tell?

I have no faith in Sparx products simply due to the obvious technical ignorance of the principal "Andy". Correspondence with this chap on a alternator issue reveals he is a mechanical nincompoop.
His products are made in China, where I happen to have a regular trade in the engineering business and I can certainly expect Sparx are being exploited or taken advantage of due to the lack of technical competence from the principal.

MikeG said:

Had one self destruct on my Norton...not quite that dramatic but dead just the same. Put a stock single phase Lucas back on and have had no troubles.

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What's that yellow spot in my mirror...??? Oh wait, it's gone.... :shock:

concours said:

MikeG said:

Had one self destruct on my Norton...not quite that dramatic but dead just the same. Put a stock single phase Lucas back on and have had no troubles.

Click to expand...

What's that yellow spot in my mirror...??? Oh wait, it's gone.... :shock:

Click to expand...

Can I borrow your battery please?? :mrgreen:

MikeG said:

concours said:

MikeG said:

Had one self destruct on my Norton...not quite that dramatic but dead just the same. Put a stock single phase Lucas back on and have had no troubles.

Click to expand...

What's that yellow spot in my mirror...??? Oh wait, it's gone.... :shock:

Click to expand...

Can I borrow your battery please?? :mrgreen:

Click to expand...

Only if you promise to keep giving it back once in a while.... :idea: :lol: