Author Topic: Another Bosch alternator rotor failure. (Read 5734 times)

bigbikerrick · « **on:** June 17, 2016, 03:31:12 PM »

Hello Folks, my Cal II auto stopped charging the other day, and after a couple of days of diagnosing, I was surprised my rotor went tits up again. I had replaced the whole charging system with a setup from euro moto electrics (enduralast) in 2013, that included a new rotor, brushes, rectifier, and adjustable voltage regulator.I also added a vented cover. it was a bit fussy to diagnose, as the rotor would work fine when cold, but once the engine got hot, it would stop charging. I bench tested the rotor, and when cold it would read 3.5 ohms resistance as it should, but once I heated it up with a heat gun, it would read zero. The folks at EME sell two different rotors, one foe $79. and one that is "oem" made in Italy for $99. the stated the $99. one is better so I ordered that one. I only got 2 1/2 years / 7K miles of use from the last one.....I hope this one is better.

I know Bosch charging systems are known to be an achilles heel, on the older Guzzis, but are there better options out there?
Thanks alot,
Rick

v65tt · « **Reply #1 on:** June 17, 2016, 03:50:05 PM »

Get the later Ducati charging system as per the v7 or breva etc

Get a local machine shop to make a taper to key adapter and your sorted

Don G · « **Reply #2 on:** June 17, 2016, 03:54:57 PM »

You can purchase the Ducati type from Euromoto and forget the hassle. DonG

Antietam Classic Cycle · « **Reply #3 on:** June 17, 2016, 05:54:09 PM »

The "Ducati type" sometimes have issues too - one I installed is on it's second regulator/rectifier. It's not a location/air flow issue either.

rodekyll · « **Reply #4 on:** June 17, 2016, 07:05:55 PM »

There is indeed something wrong with the ducati-style regulator at the design level. I've burned up abut every oem and clone variety, including the Harley crossovers, and haven't found anything that will last for me.

But the bosch rotors are crap -- break the winding wires where they exit the 'claws' due to crank nose whip/vibration. It's another design flaw. If they relieved the hole the wire comes through and gave the wire a tiny bit of strain relief/bend radiusing that wouldn't happen.

jacksonracingcomau · « **Reply #5 on:** June 17, 2016, 08:46:39 PM »

Probably no help in US but I've never had a rewound rotor fail, only genuine Bosch ones, had loads rewound in UK in 80's , problem solved
Man I use here (Australia) is COD Rewinds in Chiltern
If no-one in States does them might be worth sending a box to Rowan

I've also had genuine Ducati reg/reg fail on me, all parts have to be good in either system
Bosch system with rewound rotor & good rec/reg is bulletproof in my experience, Honda rec/reg cheap and work but you lose charge light

Murray · « **Reply #6 on:** June 17, 2016, 09:06:54 PM »

Quote from: rodekyll on June 17, 2016, 07:05:55 PM

There is indeed something wrong with the ducati-style regulator at the design level. I've burned up abut every oem and clone variety, including the Harley crossovers, and haven't found anything that will last for me.

I've had the Harley crossover (for the evo motors not the sportster) on my 1100 sport for 16 odd years and 140 000kms, every now and then I pull the mounting bolts out and hit them with a wire brush (not even running an earth wire) no issues.

rodekyll · « **Reply #7 on:** June 17, 2016, 10:03:40 PM »

I've bought the takeoffs (folks toss them for chrome), gotten the takeoffs for free (parts guy didn't have one -- sent me around back to ask the mechanic to poke through his stash) and the oem off the shelf (Dealer in Colorado collected the $$ and called ahead to Ogden where they squirreled it for me to pick up after hours -- nice effort from Harley Davidson, despite the bashing we give the marquee). That's the one I'm running now.

I had one fail in a SPECTACULAR losing-of-the-smoke event approaching Banff Park from Idaho once. There was so much smoke pouring out I almost jumped off a moving bike thinking it was in the process of exploding. My kid was riding behind me and thought I was on fire. If it was an airplane I could have sky writ my last will and testament. . .
. . . We lost a day in Windemere trying to trach down a phantom biker in the Horse Thief Creek area who might have a regulator like I needed. He didn't, but that is another adventure. We finally located one we could use in Cranbrook, 130 miles back the way we'd come. To get there I bought a big battery from NAPA and put it in a side bag. I ran jumpers from it to the bike, and we ran back south in 210 miles of miserable, driving rainstorm.

Yeah, I know I said 130 miles, but it was just that miserable. That's when I learned the evil truth of completely soaked and leaky spark plug wires as torture devices: YOU CAN'T DIE! They hurt you till you want to be dead, but then they zap you back to life. With easily another 450 miles to go In the 130 mile odyssey, I wasn't going to risk not being able to restart the bike after rearranging the wires just so my shins didn't smell like bacon. So I went for three and a half days that afternoon injecting half of the bike's coil energy directly into my bloodstream until my spit tasted like iron.

In the parking lot of the Harley dealership (they were kind enough to sell me the part, but not kind enough to let me roll it into the open bay right beside me to do the swap) I replaced the regulator as a crowd looked on (still raining) and then I brought the battery to the local NAPA, explained that as it turned out I didn't need it, and got a refund. I used the refund to buy plastic tubing, which I ran the spark plug wires through, making my DNR bracelet once again relevant and restoring my gas mileage. Then they had to come out and jump start me. I mean the bike. For some reason I wasn't at all embarrassed.

bigbikerrick · « **Reply #8 on:** June 17, 2016, 10:34:10 PM »

Thats a great story, RK!
Rick.

Murray · « **Reply #9 on:** June 18, 2016, 04:41:20 AM »

So you don't really know what the HD one is off, it is important, the skirtster only has a capacity for 22 amps which is underdone for the Ducati charging system which is rated at 26 amps. The Evo motor based regs are rated for 32amps, from memory they weren't stupidly expensive, paying for a new one will guarantee the one you get and is likely cheaper in the long run.

rodekyll · « **Reply #10 on:** June 18, 2016, 05:09:18 AM »

IIRC/FWIW, HD had two choices, a 32 amp and a 35amp.

RayB · « **Reply #11 on:** June 18, 2016, 06:49:05 AM »

Be careful with the Bosch replacement rotors from EME. I bought a spare from the to carry on my BMW R100. BMWs use a taper. The taper on the rotor I bought from EME was not machined concentric and it would wobble and rub the stator. It was a good thing I tried it out first before relying on it as a spare. I asked EME what remedy there was for me and was told my front bearing was probably going out!
I still have the OEM rotor running on the R100 with 52,000 miles on it and my spare is a known good OEM rotor.

ohiorider · « **Reply #12 on:** June 18, 2016, 06:51:42 AM »

The original OEM (Bosch) rotor on my R100GS made it from 1991 until 2005, for 94,000 miles. Wonder if v twin Guzzi vibes are harder on the rotor than the vibes from a flat twin? My first 'cheapie' (about $100.00) made it for slightly over 30,000 miles. Now on my 2nd aftermarket rotor on the GS.

Bob

Two Checks · « **Reply #13 on:** June 18, 2016, 08:44:03 AM »

Also remember the size of the BMW rotor is slightly different from the Guzzi unit.

charlie b · « **Reply #14 on:** June 18, 2016, 06:53:22 PM »

The original rotor on mine went 78k miles. I decided to get the 400W alternator from EME along with the solid state rec/reg. It has worked fine so far.

Tom · « **Reply #15 on:** June 19, 2016, 02:40:33 PM »

Have a fairly new Enduralast rotor and regulator in the Strada with a new battery. Everything seems to be fine. Charges up nicely. IIRC the new battery has 350CCA.

LaMojo · « **Reply #16 on:** June 19, 2016, 08:16:27 PM »

I would assume that the rotor coil is one continuous wire with each end soldered at the slip rings. Are these connections at the slip rings accessible?

rodekyll · « **Reply #17 on:** June 19, 2016, 09:09:24 PM »

Yes, they're accessible, but not easy to work with. They're very tight to the core of the rotor and potted/shellacked to within an inch of their lives. They're brittle and already bent too hard where they exit the core. I've tried all kinds of splicing and soldering in situ and etc. I even once managed to unwind a wire a little bit so I had something to work with. All in vain. They're the exact size, shape, and behavior of a standard pineapple hand grenade.

charlie b · « **Reply #18 on:** June 19, 2016, 09:59:26 PM »

RK, I hope you are compiling all of these little posts of yours for a book. You have a great way of putting things. :)

Tom · « **Reply #19 on:** June 20, 2016, 01:17:49 PM »

:1:

bigbikerrick · « **Reply #20 on:** June 20, 2016, 01:42:57 PM »

Quote from: LaMojo on June 19, 2016, 08:16:27 PM

I would assume that the rotor coil is one continuous wire with each end soldered at the slip rings. Are these connections at the slip rings accessible?

I can see where the wires are soldered to the slip rings, it seems the connections are intact, there is white silicone , over the area. My broken rotor reads 3.5 ohms at the slip rings,at room temperature, but when I heat it up with a heat gun, it reads zero. I am thinking there may possibly be a break in the wiring elsewhere?
Rick.

bigbikerrick · « **Reply #21 on:** June 20, 2016, 01:48:54 PM »

Thanks Fellas, for the heads up on the new rotors , and different things to look out for. I will receive my new rotor from EME today, although my rotor that failed was 3 years old and out of warranty, they did give me a "Customer courtesy" discount of 10 bucks on the replacement.
Rick.

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Author Topic: Another Bosch alternator rotor failure. (Read 5734 times)

LaMojo