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T3 not charging

Choirboy

Choirboy

Tuned and Synch'ed
Joined
Jul 16, 2010
Messages
26
Location
SE Iowa
Hello all!
I was hoping to get some advice on where to start troubleshooting my 1977 T3's charging system. The other day I was driving home from my parents, and just near the end of the ride (after ~180 miles) the bike died and would not crank. I got a jumpstart from a passing motorist but the bike would not run. No problem, I figured, my three year old lawn tractor battery must have crapped out from the long ride and heat of the day, so in goes a new battery, and the bike runs fine, but now in the twilight I notice my alternator light is on even while the bike is running (haddn't noticed it in the bright sunlight; glad it was the alternator light I couldn't see and not the oil light!!).
I looked for any wires the might have jiggled loose and did not find anything obvious; I pulled off the front cover and noticed that there is a bit of soot on the cover as if I've been arcing from the big 3 wire plastic plug (which had some chips out of it exposing the connections and was so brittle it disintegrated when I touched it). Many of the wires under the cover are extremely hard, not supple as I expected wires to be. I noticed that my T3 does not have the plastic spacer between the case and the front cover that my dad's convert has.
Any advice on what to look for and how to test things would be greatly appreciated!!
Jon
 
Check the rotor. If the field windings are shorting to the poles the ligt will remain on. Rotor failure ios the most common cause of failure, especially on bikes with no cover spacer.

Pete
 
Since I have a high mileage T3, I'll reinforce the rest. I've gone through several alt rotors, it is the usual culprit. The fact that the triple plug has disintegrated is very common, & not a problem as long as the wires are intact. Plastic spacer won't restore the connection, but as said may help a bit to prevent the next rotor failure. One other thing that isn't your problem this time but could be next time-namely, I know it's hard to believe, but if the charging light bulb blows-or even if the bulb socket goes bad so the light doen't come on-the bike doesn't charge. Really. So if some day the charging light doesn't come on with the ignition on & before you hit the starter button, you gotta deal with it, or you'll be walking.

A couple other tips: For a battery substitute down the road, if happy with open cell lead acid, & I am, I've been using Interstate SP-30R with great results pretty much forever, available lots of places & with the terminals properly placed. Also, when the battery gets too weak to turn it, as long as its not completely dead it's pretty easy to jump start yourself if you know how. Namely, with bike in 2nd gear, back up the bike until it stops allowing you to push it, which means you are back up the compression stroke, & when you go forward you get one free spin of the motor before it comes up against the compression stroke again. Then pull in clutch, run with the bike, jump in to the sadlle, pop the clutch & if everything is in order buke should dstart right up. Done it many times. Finally, suggest you get a voltmeter. That way next time the rotor takes a dump, you see it right away & know to shut off the headlight pronto. Without the fuel pump, ECU & other electronic stuff on the newer bikes, you can get 200 miles on a fully charged good battery. You can actually get home that way, always spending the night somewhere you can get the battery recharged after you stop fopr the day. Also worth a lot in piece of mind to know the thing is charging-when it is.
 
I apologize for the dumb question, but how do I check the rotor windings? I know my way around a volt-ohm meter but electronics have not played a large part in my mechanical training, sort of a correspondence course by Haynes :? Any help with the procedure would be appreciated.

Also, are there any resonably cost effective upgrades to the alternator? I'm fine right now, but worried that once I add a heated suit for my wife, along with the H3 headlight, driving lights and heated grips I've already added, I might start getting a bit low on the juice! I seem to remember reading in a Guzzi book about the LAPD putting in some japanese alternator as an upgrade, I'll see if I can find the quote later. Thanks!
 
The quick check of the rotor is with the brushes not touching the slip rings. With an ohm meter measure the resistance across the slip rings. You should have 6.9 ohms +/- 10%.
 
You may already be beyond the capacity of the stock alt, never mind adding the additional electrics. Don't bother trying to adapt the Saprisa charging system from some later Guzzis-it is a lot more reliable than the Bosch but not really higher output. The real solution for you would seem to be the Enduralast system from euromotoelectrics.com. Somewhat expensive ($500) but produces 450 watts/32 amps max-or 20 amps (max for Bosch at any RPM) at only 2000RPM. I've never gone that route cause I don't run all the added electrics you do, but I've seen good comments about this system in the usual places. (Probably here somewhere, plus wildguzzi.) FYI, they also sell & service the Valeo starter, much stronger but not really needed for the small valve motor in your (& my) T3. There may be 1 or 2 other alternative charging systems that others can point out.
 
Thanks for the great lead! Unfortunately, $500 might be out of my budget for an upgraded alternator... at least at this point. I try to never run my heated grips at the same time I use my high beams (high beam and spots switched together) to try to avoid over taxing my system. I was hoping for "this alternator puts out more power and costs less than the stock one" but I guess that is not to be :-( My wife will just have to wait a while until she gets her heated suit!
 
I went through a similar problem. Make sure you're running at least 3,000 RPM consistently or you may not charge the system.
 
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