Alternator output correction


Little mate
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Alternator output correction

Post by Little mate »

Well tonight I checked in to my alternator output and got 50 ohms at the connection , this is not good . So I removed alternator , cleaned and polished the 2 rings on the rotor with 2000 grit fine emery cloth ,also polished the contact end of the brushes . Reinstalled on the bike and checked again .i know have 5 ohms resistance at the connector. This is a huge increase in output using ohms law to calculate, I went from 2 amps output to almost 28 amps output. So now on to the voltage regulator / rectifier and maybe I can get it to run again. All input from anybody great fully appreciated I ma still be missing something

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Re: Alternator output correction

Post by Larry Zimmer »

Good to hear! Be certain all the connectors are clean and corrosion free. Even a half ohm across some of these can make a difference.
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Little mate
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Re: Alternator output correction

Post by Little mate »

Yes Larry a ohm here and there of a los can make a difference between a bike that runs and one that won't. Still trying to figure out the lack of fire in 2 and 5, and yes they share the same ignition components, but could a bad rectifier take out the igniter.

Little mate
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Re: Alternator output correction

Post by Little mate »

I spun the rotor by hand when I had the alternator of the bike and could hear the sound of rubber rubbing , I lubed the new seal and o ring when I installed it . Did I miss something ? I have the spring side of the seal facing the bearing .

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Re: Alternator output correction

Post by steve murdoch icoa #5322 »

Couldn't the "lack of fire" in 2 and 5 just be a bad coil?
Can't think where the sound of rubber rubbing would be from
Tons of charging info, even in the FAQ questions at he bottom of the page, in this article from Mike Nixon.
http://www.motorcycleproject.com/text/c ... lutch.html

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Re: Alternator output correction

Post by daves79x »

I've not commented because I really can't follow your 'shotgun' approach. The alternator has nothing to do with the ignition system at cranking speed. Your charging system needs evaluated one part at a time, but so does your ignition system. Two separate problems. These alternators are pretty simple (if you follow the shop manual on reassembly) and if all it's components check out, then look for a bad regulator or some melted wires. Replace anything that's been warm - don't just cut and splice.

Tests on regulators are pretty worthless - just try a new one.

You likely have a bad 2-5 spark unit. Coils rarely go bad and pulser units never do. But this does not take into account crappy wiring, miss-wiring and other external issues.

Dave

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Re: Alternator output correction

Post by Little mate »

Thanks Dave for your input and yes there was a lot going on,bike ran fine until alternator locked up. The bike then sat for about 2 months and where I live with high humidity and salt air it does not take long to screw up your carbs , that's why I initially thought it was a carb problem . Cleaned carbs 2 and 5 and set mixture screw to original position . I had a spark at the plug maybe a weak spark. So I was confused ,I tried the screwdriver test at the pulse gen and got no spark . That's why I thought it may be the spark units .any input greatly appreciated ,and thanks again for your input.

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Re: Alternator output correction

Post by Little mate »

Thanks for your input Steve I originally thought that to so I changed the coil and cleaned the contacts. With no luck.

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Re: Alternator output correction

Post by Little mate »

Today I will swap the coils around just in case the one I had in my spares was bad ,as I can't be Shure . I did have 1 igniter go south on me last year. But only when it got hot.after 10 minutes of riding and it was intermitent.a bad coil would make sense.

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Re: Alternator output correction

Post by daves79x »

If your regulator happened to go bad before the alternator locked up, then it could have fried ignition components. When you do get it running, I wouldn't run it much before verifying the charging voltage. If you have a bad regulator and everything else is fixed, you'll be right back where you started from (except the frozen alternator bearing).

Dave

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Re: Alternator output correction

Post by Little mate »

Hi Dave that's what I was thinking at the start. But here is what we have now. Got it running a bit better . I switched the coils around and still had Luke warm header at 2 5 was little hotter but not where it should be. Voltage went to 14 and dropped to 12 a couple of times , so I shut it down , then tried again it went to 12 maybe a little past that's it

Little mate
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Re: Alternator output correction

Post by Little mate »

The voltage regulator is set to limit 14v max. I haven't tested the output from the alternator today at the battery. I was getting 13.5 but it's anybody's guess what it is now. I have to be systematic on this as there is more than 1 problem , back to alternator then rectifier once I have that resolved , then deal with the ignition any thoughts on this much appreciated.

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Re: Alternator output correction

Post by Little mate »

I am lucky to have good friends and a loaner v t x to use for the old man Raleigh at thanksgiving and for that I am great full , but would have been nice to ride my Cbx I built back in 89/90 .

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Re: Alternator output correction

Post by daves79x »

Have you done the most basic check on the rotor? Resistance should be close to 4 OHM or a bit more between the slip rings. More than that or less and the rotor is bad and this is by far the most common failure in these alternators apart from brushes.

Dave

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Re: Alternator output correction

Post by Little mate »

Hi Dave I thought I had included that in my post , but after reading thru I realize I had omitted that . So to answer the question it checked good in spec and the yellow wires checked good also. Yep it's got me. So was about to check wire diagram to see where voltmeter is connected . I assume it's after the regulator ,that would explain the fluctuation as it was limiting it to the 14 volt max.

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