Topic: Sanglas 400Y-Yamaha XS400. What's the alternator power output? (with pics)

[Raul CB750K1]

My spanish-made Sanglas 400Y died on me yesterday on my first test ride. I was about 15 miles away and I told the bike: "listen you #$%*, I've spent hours on you changing your starter motor, thoroughfully cleaning your handlebar switches, connectors and fuses. I have replaced your old blinkers, have put heating grips, change the oil. You are not going to leave me stranded."


But she did. I tried to kickstart it until I was exhausted. I knew it was a battery issue -obviously the starter wouldn't spin, just the faint "click" you have heard before. As I have been tinkering with it in the shop, I knew the battery was a little low. In fact, I kickstart it when I left home, but it should have recharged on the way.


But it didn't. During the short trip I connected the heating grips to check how much you can feel the heat. At the first stop light the bike died and couldn't start. Finally I decided to ask some car driver on a nearby gas station to jumpstart it. On the way to the gas station there was a car shop; asked for a little help and they came out with one of those portable battery with cables, and the bike started quickly at the third or fourth try.

I switched off the headlight and could make it back home. Of course, if the bike was running with an empty battery, it could only mean that the alternator was doing its job. Yesterday afternoon I charged the battery, and this morning I did some measurements.


With the engine off, and the headlight and heating grips on, the battery drawed 7 amps. With the heating grips off, about 6 amps. With the headlight off -only position on-, about one amp. That amounts make sense.

Now, with the bike started, at idle the battery was still drawing about four amp with the headlight on. I needed to rev it up so the current would stay about -0.5 - 0 - 0.5, but if I switched the headlight off, the charging current was about 4 amp.


So, it seems that the alternator doesn't give enough juice to charge the battery and power the lights. It seems odd to me, but as it was not mandatory to have the headlight on 25 years ago, maybe the manufacturers didn't think it was necessary a bigger alternator.


I'll search on the internet for the XS400 alternator power. In any case, and even when I cleaned all the connectors, maybe I will replace them altogether for new ones.



Raul

[Raul CB750K1]

I just found the data in the user manual. 12V-180 W. That's more than enough to feed al the electric devices on the bike.

I guess it's time to renew some connectors.

[bryanj]

Raul, I do remember that Yamaha had the least reliable electrics of the japanese at the time the XS400 was made,
I know the XS750 went from combined reg/rec to seperate and back to combined over a period of only 18 months it would be well checking out the voltages at the reg rec. Email me direct and i will give you some ideas.
Regards Bryan

[Raul CB750K1]

The bike is a blast. With it's low weight and size, it has a powerful motor that reaches the ton with almost no effort. Articles of the time states that it had the best of both worlds, the japanese engine with the superb spanish frame. And it handles like a dream too, much better than my CB750.

It has a small oil leak after you run it, and I was putting the blame on a bad seal of the alternator cables. I tore down the sprocket cover to put some sealant, remove the cable shield (hardened by age) and look at what I found.... plastic sleeves hardened and broken. Somebody had already use duct tape, but it was not good enough to me. I spliced the cables, soldered new ones and used heat-shrink to protect the connections. The leak reappeared, so I will have another look. I guess it's a problem of the sprocket axle seal, or clutch rod seal.

Regarding the electrics, you are right Bryan. It has a separate regulator and rectifier. With the bike stopped, the battery reads 12 volts, while with the engine started the battery reads about 14.4 volts. That seems good enough. In theory, when the output voltage gets above 14 volts or so, the regulator should reduce the current to the field coil, thus reducing the magnetic field and the output voltage.

We had a Sanglas club ride yesterday and the bike behave like a champ. We did about 120 miles, and I had no charging issues. I didn't run the headlight, though I used the parking light and the heating grips most of the time.  There you have a picture of me riding my actual bike; it's lacking the left side cover and the headlight cowling. While I restore my 100% spanish Sanglas 400 thumper, it's good to ride this "ugly duckling" that people despise and I was able to buy for 500 euro. Of all my five bikes, this is the one that has given me more pleasure for the money put -and I have ridden it only twice-. It is like the "swang song", the desperate effort of the spanish industry to survive. Actually, mine was registered on dec 12, 1982. In january the next year, Sanglas was fully bought by Yamaha and they didn't offer Sanglas bikes anymore, but the XS400 instead. So mine is one of the latest, that gives a little "charisma" to it. In fact, the technical document states that the manufacturer is not "Sanglas" but "SEMSA", that stands for "Spanish Engine Company Ltd" -or so-, a joint-venture between Yamaha and some banks to take over Sanglas and "resurrect" it. History showed that it was just a way to let Yamaha take over and some banks make a BIG profit.

[bryanj]

Raul, just got back to re-reding the "old" posts, Check your AC output on all three "Pairs" with engine running. I had the only 500 I have ever seen with weak charging (YES MINE) and the windings were physically damaged with a wire broke so it charged with light load but not enough for everything. All i did was solder the broken ends together and 100% again!

[Raul CB750K1]

Raul, just got back to re-reding the "old" posts, Check your AC output on all three "Pairs" with engine running. I had the only 500 I have ever seen with weak charging (YES MINE) and the windings were physically damaged with a wire broke so it charged with light load but not enough for everything. All i did was solder the broken ends together and 100% again!

I got your email Bryan. There are a few more things from the bike I need to take care of, like replacing the carb-to-engine rubber boots, the blinker relay etc. I already bought new faston connectors and plastic blocks so I will be renewing cables and connectors here and there, and while I'm at it I will check the alternator output as you directed.


Raul

[crazypj]

 I have a generator for XS400 but it probably wont be worthwhile due to shipping costs from Florida
PJ

[Raul CB750K1]

I have a generator for XS400 but it probably wont be worthwhile due to shipping costs from Florida
PJ

Thanks for the offer. I had a damaged rotor so I bought another one a while ago. It was a rotor+alternator set. Surface shipping was about 30 bucks, fortunately I bought the auction at 10 bucks or so....

[Bar50]

I know that about half of all the XS 650's I have had need new alternator brushes.  Cheap at $15 if you already have it apart. Link : http://www.mikesxs.net/mikesxs-electrical.php?category_id=2.3
I do not know if they are the same, I have only worked on a set of carbs or two on the XS 400's...
Good luck!

[Raul CB750K1]

I know that about half of all the XS 650's I have had need new alternator brushes.  Cheap at $15 if you already have it apart. Link : http://www.mikesxs.net/mikesxs-electrical.php?category_id=2.3
I do not know if they are the same, I have only worked on a set of carbs or two on the XS 400's...
Good luck!

No, they ain't the same. The XS400 alternator doesn't have brushes. There is a stator and a magnet coil, and the rotor interrupts the magnetic field to generate the electricity.


Raul

[Bar50]

Like I said, never messed with the electrical side..just trying to help...sorry