Regulator for 1974 GT250

[Deucea]

I have a simple question for the group. Does the 1974 Suzuki GT250 have a regulator. I know it has a rectifier, and the parts list shows the regulator. I have looked everywhere. So the question is, does the 1974 Suzuki GT250 have a regulator and where is it located. And let me know what the part number is for it.
Thank you

[tz375]

I can't tell you if your bike had an old style regulator, but I have started to use modern combine regulator/rectifier units from a couple of sources. Latest one is from Sparckmoto.com. They they have two types and Matthew can tell you which would work best for your bike.

Old style units do not do a good job of regulating voltage tightly enough for either AGM or LiPo type batteries, so if you are thinking of perhaps using modern battery, it might be a good idea to update the charging system to go with it.

[Deucea]

Thanks tz. I've been having charging issues with my 74 GT250. The tech that's been working on my bike only checked at the battery, and saw that I wasn't charging the battery. He was in a hurry, and told me to bring it back in a day or two. In the mean time, I've been checking around for parts if I need them. You can still order a rectifier, and alternators are no longer available. The parts list shows a regulator, but no numbers. For the life of me, I've never seen one on my bike. I'll check out Sparckmoto, and thanks for the quick answer.

[jabcb]

When stock, your 74 GT250 does not have a voltage regulator — it uses the battery as the voltage regulator.
Because of this, you should use a conventional battery that you add water to.

I usually recommend upgrading to a modern rectifier/regulator, which will allow you to use an AGM battery.
I’ve had good results with a Tympanium rectifier/regulator, but the one listed on the Sparck Moto website is cheaper.

The GT250 was able to get away without a voltage regulator because it uses a lighting coil that is only switched on when the headlight is on.
You can change the wiring to increase the alternator output when you upgrade to a modern rectifier/regulator.
See the 3rd wiring diagram here: viewtopic.php?f=29&t=6786&p=121472&hili ... or#p121472

[Deucea]

Thanks Jabcb, this is very helpful. I was going crazy because the parts diagram shows a regulator, but no numbers. I'm definitely upgrading the rectifier, and I'll show my electrical engineers your schematic. All good.
Thank you very much.

[markush]

Hi!
Some late GT250A-B could have a regulator. (For USA and Canada market, perhaps experimental use by Suzuki?)
Then it's the same part as on GT500.

[Deucea]

Marush,

It's me Bruce A. from Wixom Michigan USA. We have emailed each other before. Last year I had my crank seals all redone, and the smoking problem has gone away. Now it's electrical. Thank you for the update on the regulator. I will look for it. But now at least I have a part number to go by. Once I find out about the alternator (if I need to replace/rebuild) I'm definitely going to change out the rectifier with a more modern unit. I've printed out your pages in english on "electrical." I'll probably be asking about the alternator. You can't buy new.

Thank you for the regulator part number.

[markush]

Hi Bruce!

It's me Bruce A. from Wixom Michigan USA. We have emailed each other before.

Yes, I found the Emails, from 2011.

I'd posted about the Regulator as info only. I think it would be better to use a Rectifier-Regulator-Combination from the accessories as to use some of the old stuff.
But you don't need necessarily a regulator when the electrical system is in the original condition with recommended wattage bulbs and an intact standard battery is used.

[Deucea]

Markush,
I am using a wet-cell battery, and the original lights. It is a little dim, but I don't plan on riding at night. The problem is, after the bike warms up, if I use the headlight and turn signals, one of the cylinders stops working. If I turn off the lights and stop using the turn signals, everything is fine. My motorcycle mechanic and good friend Dave O from Ozone Bike Works, measured the voltage going back to the battery at 5,000 rpm. It was 11 volts. So he's going to check the alternator soon. In the mean time, I know where to get a replacement rectifier. The alternator we worry about when the time comes.
Thanks for your help. Your site is very informative.