Battery charging is critical

Post by **Suzsmokeyallan** » Sat Aug 29, 2009 9:14 pm

Since having a failed diode in the rectifier pack on my 76 Buffalo recently it made me more aware of how IMPORTANT the correct state of battery charge is to the bikes engine performance.
Whenever you have any engine running issues, however insignificant you might think they are related to battery charging, check the charging rate first on the bike to make sure its to within spec.
One of the best updates you can do to your GT is to replace the old points type regulator with one from Anthony at Oregon:
http://www.oregonmotorcycleparts.com/vregulators.html
These electronic units are first rate and well built, plus they are output adjustable to a degree by a 'pot' and will 'cycle' at lower rpms than the stock unit for a more stable charging rate. Anthony is willing to work with you on your particular bikes needs so send him an email for other models of bike not listed.

You can also put in an integrated unit such one as this that replaces both regulator and rectifier:
http://www.electrexworld.co.uk/rr77-reg ... 863-0.html

The way the engine performs as the battery slowly discharges is interesting, and as such the problems seen change accordingly.
So be aware of just how good your battery and its charging rate is before thinking you need to pull something off the engine to clean it etc.

Craig380 · Post by **Craig380** » Tue Sep 01, 2009 2:08 am

I really, really must get the charging system on my 380 sorted. I suspect the rotor windings are shorted, but electrics are a black art to me. Substitute rectifiers, regulators and brushes have all failed to fix the problem

It's been running 'total loss' for 5 years, which means I can get a good 2 hour ride on a fully battery charge ... which is OK for a weekend ride.

By searching through the Varta battery catalogue I found a 12Ah / 120A unit that just fits the battery tray, giving me a bit of safety margin.

From experience, the first I notice is the LED gear indicator getting dimmer, then the bike will run very erratically under 3,500rpm (current draw for the coils is higher at low rpm), then it won't run at all under 4,000rpm, then it quits altogether

Post by **Suzsmokeyallan** » Tue Sep 01, 2009 8:31 am

Craig why not perform the tests on the rotor and windings to see if its actually good. If you do trace the fault to that part of the system and have a Kokusan Denki unit now would be a good time to upgrade to the better ND unit

Craig380 · Post by **Craig380** » Tue Sep 01, 2009 9:25 am

I'm gonna get someone that knows how to use a mulitmeter properly to do it

I can do anything mechanical but I have zero experience with electrical stuff ... even if I had a decent meter etc I would not fully trust my measurements

H2RICK · Post by **H2RICK** » Wed Sep 09, 2009 9:00 am

Craig, measuring resistance with an ohmmeter is the most basic procedure in the electronics world. The only thing you have to remember when checking resistance is that there must be NO voltage in the circuit......otherwise you will fry the meter (or pop the fuse in the meter, if it has a fuse). When in doubt about voltage in a circuit you are testing just disconnect the ground strap from the battery before starting your test(s).
The whole procedure is NOT black art or rocket science. You can buy VERY cheap digital meters these days (typically C$10 - $30) so if you DO have an "accident" with it, you haven't thrown away a whole bunch of money.

tz375 · Post by **tz375** » Wed Sep 09, 2009 9:42 am

Craig,

Typically the alternator has 3 yellow leads and one green.

Disconnect the plug from the alternator and test the alternator side of teh plug.

Set you multimeter to OHMs and put the probes on any two of the yellow leads - lets call them 1-2-3. Note the reading - probably 1.0-1.5 ohms. Then repeat of say 1-3 and then on 2-3 pair and all three readings should be very similar.

If one or other of those readins is zero, then a wire is broken (open circuit).

Then test between lead 1 and ground and repeat for the leads 2 and 3. All should be infinity (typically 1 on a digital M/M). If one or more are connected to ground you have a short and the stator needs to be replaced or rewound.

Testing the rotor is only slightly more complex. There are two brushes and one is connected to that green lead and the other goes to ground.

Test from the green lead to ground and it should show a connection with low resistance. If not, the lead is broken or a brush is worn. Fault finding is a simple step by step process.

If it's OK, then take off the alternator cover and slip a thin piece of card or plastic between the carbon brushes and the rotor. test between the two rotor slip rings small resistance good, no resitance at all, bad, infinite also bad. test from the brush end of teh green lead to teh connector end to be sure that has a connection and very low resistance.

If the stator showed up as open circuit, test each of the yellow leads to see if there's a break between the connector and the alternator - That's often the problem.

Just take your time and you wil open a whole new world.

Good luck

Craig380 · Post by **Craig380** » Thu Sep 10, 2009 2:52 am

thanks very much for putting it in plain words, TZ -- that's a great explanation. I will borrow a meter and give that a go.

cheers, Craig