ALTERNATOR

[cbxal]

Does anyone know how thick the plates are supposed to be ? , And what the spring should measure uncompressed. I removed the alternator to check to see if they were slipping. They look grooved a little but not so bad that they would not be useful, They do look a little thin to me but I do not know how thick they are supposed to be.Any info would be greatly appreciated.

[andy]

While in there, replace the brushes, they are only good for 15,000 - 20,000 miles, tops.

[EMS]

I am not sure, that there is a thickness spec. The paltes are designed to slip, so the faces will show some kind of wear (grooves). You should have four radial notches in one of them and they should be prominent. Maybe they were there to indicate the service limit.
I could swear reading a number in the service manual for the height of the uncompressed spring, but I can not find it anywhere. Sorry.

[Passx]

Just a question on the clutch plates,

I've been thinking of having the plates lines with a thin friction material, we have a clutch rebuilding shop in the area and they do a lot of custom stuff for racers in the area. I realise that the plates would have to be machined to accomodate the added thinkness but is really not a problem. I figured that if I added a friction material to them when they wear out it would be a simple matter of bonding new material and you'd have new plates and since the big "H" seems determined to rid itself of all it's old bike parts we have to think ahead. Thoughts, opinions, any personal experiences ?


Steve P. # 5220

[Jim-Jim]

First, newcomers should remain aware that the alternator clutch is there for a reason and is designed to slip to prevent the heavy rotor inertia from overstressing the primary chain and other parts when the motor accelerates. I would be very cautious about increasing the friction; there is no gain in charging unless the clutch slips all the time. That said, the free length of a new spring is 1-7/32". The overall thickness of both the A & B plates is 27/32". The thickness of the facing plate is hard to measure as the top edge is rounded but on the A plate (with slots) is about 9/64"; the B plate (smooth) is slightly less at 7/64". There is a excellent writeup in one of the old Xpress by Tim Ware that covers this area very well. Clutch slippage has been cured in various ways; some say it is caused by too much friction reducing additives in the oil; some say they have cured it by having the faces turned smooth (minimum removal) and adding a thin washer to compensate for the removal; some have done a similar thing by laying the plates on a flat surface (glass) under very fine emery paper or sandpaper to remove some of the ridges; others have simply replaced the plates and springs (they are all still available).

[cbxal]

Well I checked the plates and they look pretty good. The spring measures what it should. I hooked up the alternator to the bike and turned on the key and it's not getting magnetized.Nothing would stick to the case. Ohm's are at .5 for the stator nothing at ground. Brushes do not have a scribe line , but look about a half inch long sticking out. I am stumped . Is there a way to test the rotor ? Or is the stator definitely bad if not magnetizing. Any info would be appreciated. Thanks.

[Jim-Jim]

According to the manual, you should make the following checks:
1) Measure across the slip rings on the rotor with an ohmmeter. You should measure 3.5 - 4.8 ohms.
2) Measure the yellow leads from the stator; all should have continuity with each other, if not, one winding is open. Also check each yellow lead to ground (frame of the stator) - if there is continuity, the winding is shorted to ground and the stator should be replaced. The resistance of each winding (between any two yellow leads) should be .32 - .40 ohms. All the windings should be very close in resistance to each other. I wouldn't be too worried if it is a little high but they should all be close to each other. If all this is OK, then look to the regulator. It's the regulators job to feed a little voltage back to the rotor to generate the rotating field into the stator. If the regulator isn't - no stator output. If you are really careful, you can just brush the rotor slip rings with battery voltage (REALLY QUICK AND BRIEFLY) - if it magnetizes, it is probably OK. Just a quick tap or you'll burn the rotor winding out. Your brushes should have a scribed line but 1/2" should be plenty of contact. Just to double check the internal cable wiring, you can check the rotor resistance by checking it at the plug into the regulator between the White/Black leads - this will check the wiing down through the brushes through the winding and back up to the plug. Let us know.

[Jim-Jim]

According to the manual, you should make the following checks:
1) Measure across the slip rings on the rotor with an ohmmeter. You should measure 3.5 - 4.8 ohms.
2) Measure the yellow leads from the stator; all should have continuity with each other, if not, one winding is open. Also check each yellow lead to ground (frame of the stator) - if there is continuity, the winding is shorted to ground and the stator should be replaced. The resistance of each winding (between any two yellow leads) should be .32 - .40 ohms. All the windings should be very close in resistance to each other. I wouldn't be too worried if it is a little high but they should all be close to each other. If all this is OK, then look to the regulator. It's the regulators job to feed a little voltage back to the rotor to generate the rotating field into the stator. If the regulator isn't - no stator output. If you are really careful, you can just brush the rotor slip rings with battery voltage (REALLY QUICK AND BRIEFLY) - if it magnetizes, it is probably OK. Just a quick tap or you'll burn the rotor winding out. Your brushes should have a scribed line but 1/2" should be plenty of contact. Just to double check the internal cable wiring, you can check the rotor resistance by checking it at the plug into the regulator between the White/Black leads - this will check the wiing down through the brushes through the winding and back up to the plug. Let us know.

[cbxal]

I cant thank you guys enough. I would be lost without your help. This is my first cbx and I am no motorcycle mechanic as you can probably tell. So I checked the rotor slip rings ( I assume they are the two copper rings that the brushes contact ,) and it reads 1.0 ohm's . My volt meter is a fluke and I only have one setting for ohm's. So I think I am going to order a new or rebuilt rotor. If this doesn't sound like the cause of my problems to you please let me know , I hate to buy parts I don't need. I already bought a new regulator and it didn't solve the problem. This is why I am consulting you experts this time. Again thank you for all the help. Thanks.

[Jim-Jim]

Al, Fluke is one of the best meters; if it says 1 ohm, that's what it is. 1 ohm is too low. Did you check the stator? You should measure 0.3 - 0.4 ohms between each yellow wire and 0.0 ohms between any yellow and the frame of the stator. The important thing is that all the yellow lead measurements should be very close to each other. If you DO replace that rotor, I would like to buy the old one from you. I can use it to test in a circuit to determine exactly what is wrong with it and how it can be checked for. That would help me learn a little more about how this all works. I'd be happy to pay a fair price (+shipping, of course). Let us know how it works out and let me know about the old rotor.

[cbxal]

Thanks Jim-Jim, The three yellow wires to the stator read .7 ohm's ,but they were all the same. Do you know what the white wire is for.? thanks.

[Jim-Jim]

Al, you should have 5 leads from the alternator; 3 yellow for the stator and 2 (White and Black) for the rotor. (?)

[sr71cbx]

---A quick way to test the rotor is to turn on the ignition key with a FULLY charged battery and hold a feeler gauge near the alternator case on the bike,if it sticks to the alternator,it's a fair assumption that the rotor is OK,although an intermittent short can raise hell with troubleshooting.......

There's a couple of places on the 'net I found that can rewind or rebuild rotors,don't toss the old stuff out! :) Same goes for stator windings and aftermarket reg/rectifiers are also available,been using one of those in my turbo bike for 11 years now.($100 as opposed to $200---yeah,I'd go aftermarket...)

Good luck on your troubleshooting,I also concur with use of a Fluke VOM or equivalent digital meter........analog stuff does in a pinch but not for precise troubleshooting.

[Don]

Some feeler gauges are stainless, and it the one you have is, you won't learn a thing ;)



What really gets magnetized is the rotor shaft - If you have the alternator off the engine, hold a screwdriver tip near the nut that holds the clutch half on the alternator and turn on the key. If the shaft is a magnet, the rotor is good, and the regulator is supplying current to it.



Don

[sr71cbx]

Don,

Point well-taken,a small steel screwdriver will attract itself to the outside of the case too.