Alternator? Rectifier? Ouch...

CrashTestDanny

started a few weeks ago, the bike died and wouldn't start up again... old battery, ok, replaced that... Now it's happening again, and the ESV shows 15V with switch off and 14.8 with switch on. :(

Anyone know of a source for after-market (i.e. less expensive) alternators for the ST 1300?
 
We need more symptons....

FI coming on?


It could be the kill switch or maybe the kickstand down switch...both of those have be known to cause this problems.
 
FI is not coming on... when the bike is rolling down the road the battery is draining. When it gets low enough the speedo/tach/headlights shut down with all the LED stuff still on. A few minutes later and I'm coasting - which only works well on the downhill stretches...

Seems like kill switch or kickstand switch would just cause the bike to shut down? Has anyone actually seen these to interfere with charging without killing the bike?
 
Well, I haven't quite got the alternator out yet.. the throttle body is off and next step is to pull the radiator... I would have rather had a stealer do this, but pretty sure I can't afford the bill...
 
hoping it's something other than the alternator itself since that seems to be a $500 part from direct line...
 
Ok, I got the alternator out today and was looking at the charging system troubleshooting steps (chapter 19 in the SM). It says to check continuity between the stator coil and the case, but the accompanying picture seems to be showing checking continuity between P2 on the rectifier and the case. If the picture matches the words, then it seems that my rectifier fails... sound right? Much rather replace the rectifier than the whole alternator - for obviou$ rea$on$...

BTW - getting that bottom bolt out was a real adventure - not for the faint of heart...
 
There have been people that have had the alternator die on the 1300 but it isn't that common. While I don't think there is an aftermarket option, if determined that it is bad I would check around with some of the alternator rebuild shops. They may be able to rebuild it. It is worth a shot being you have it out.
 
ok, after sleeping on it, I re-read section 19 and here's what I have found:

I can't get the alternator front and rear covers separated. Manual suggests that just those two 8mm nuts on the front hold the covers together, but it seems like there is also something internal.

The remaining troubleshooting steps can be performed without disassembling the alternator, but I wonder if they are valid before disassembly? Any thoughts?

The manual says to check the resistance between the slip rings and it should be 0.1-1.0 ohms. Mine is infinite, which indicates a bad rotor coil if the test is valid.

The manual says to check the continuity between the stator coil wire and the case and there should be none. My stator coil wire would seem to be grounded somewhere, but again, I wonder if this is valid without disassembling the alternator...

Any thoughts on how to separate the covers? or on whether these tests are valid prior to doing so?
 
I have always found that it is best to troubleshoot alternator problems before taking the alternator out. If the ST1300 is the same as the ST1100 there should be three alternator wires that go to the regulator rectifier. Disconnect these, each should be checked against ground and should not show any connection to ground. I have found many cases where there is no ground but under load the alternator coil will short to ground. The next test is to do a running test. With each of these wires disconnected you should start the engine and with an AC Voltmeter check the voltage between any two of the three alternator wires. I am not sure of the actual output vs rpm but it should be in excess of 50 volts. The important part is to make sure that all any combination of two of the three wires read the same output. If one coil is bad in the alternator one combination will either read low or not at all. This will tell you if the alternator is functioning correctly. If it checks out the only other thing is the regulator rectifier. Chances are if the alternator output is good the regulator rectifier is bad. Again, I am not an expert on the ST1300 charging system this is how I would check an ST1100.

Dan
 
Warning: the 2003 manual I have has some flaws in the electrical department.

I recently experienced problems with my alternator, so I dug it out as well, to a chorus of muttering and grumbling about Honda engineers..

According to an alternator repair shop around here, the rotor should measure around 3.3 ohms (manual says .1 to 1 ohm) between the slip rings, and have infinite resistance between either slipring and the rotor shaft.

My stator also showed continuity between the wires and the case. I checked a BMW manual which mentions the same test, but only after removing the stator wiring from the rectifier board.
I concluded that the test had a flaw and that I was measuring continuity through one of the diodes.
I also concluded that I could only find continuity when I was measuring one way. When I reversed the probes (reversing polarity) I found no continuity.
Unfortunatly, I only figured this out with the help of a used alternator which I bought..

So: if the rotor is open circuit, that's your culprit.
If the stator only shows continuity in one direction it's not shorted.

One more thing, the alternator can easily be checked by a automobile electrics shop, as it's really just a small car alternator.

HTH, Dani
 
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So compared to infinite, I would think there's not a lot of difference between 3.3 and 1.1... :) Infinite seems bad to me, I was just wondering if being inside the magnetic field of the stator coil would cause that... I don't think so, but I'll probably split it when I get off work this evening just to be sure...

Thanks for the tip on the stator - might mean the difference between buying a whole new alternator and just repairing this one... although I'm leaning toward replacing the regulator at the same time just to be safe, at which point I'm not sure if a whole new alternator is not such a good idea... Or one of our friends here offered me a used one for about $200, which may just be the deal I need....

Don't mutter too much about those Honda engineers - the ST1300 is still a fantastic product!
 
Ok, ordered new alternator assembly (regulator/rectifier included) from Ron Ayers @ $509 and all new radiator /water pipe hoses from direct line (ever notice that each has some parts for less and some parts for more than the other?)

Anyhow... about $800 for everything. The alternator is definitely failed - open circuit in the rotor coil. Could probably replace just the rotor coil for about $250, but then will be kicking myself when I have to tear down again for the regulator which is almost $200 again...
 
Good man.

I was very glad that my alternator was allright as the very same unit costs $1500 overhere ::eek:

Now you can have fun putting it all back together ;)

That lovely moment when you press the starter button, check the voltage and find it is charging..

Regards, Dani
 
CrashTestDanny said:
started a few weeks ago, the bike died and wouldn't start up again... old battery, ok, replaced that... Now it's happening again, and the ESV shows 15V with switch off and 14.8 with switch on. :(

Anyone know of a source for after-market (i.e. less expensive) alternators for the ST 1300?
Click to expand...
My ST1300 alternator died and left me stranded at about 60,000 miles. I didn't notice the voltage going down. (I've since added a volt gauge). I determined it was the alternator and replaced it. It was $500 about 5 years ago. I tried to get it overhauled at a local alternator repair shop that I've used before, and trust. He said parts aren't available to fix it.
 
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