Gt250 running without battery.

All to do with wiring, charging or just trying to figure out whats gone wrong.

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zk0ot
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Gt250 running without battery.

Post by zk0ot »

One of us in the group got a gt250 cafe project.

The wiring is....... less than desirable. Wire nuts. Loose ends. Miscolored. Toggle switches. Etc.

Can stock ignition handle running battery less ? It look to have a reg wired up.

Just trying to determine a plan of attack


New harness. Wire as designed.
New harness. Wire as battery less.
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jabcb
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Re: Gt250 running without battery.

Post by jabcb »

The GT250 uses the battery as a voltage regulator.

The alternator spec is that charging starts by 2k rpm.
I have a T350, which has pretty much the same electrical system, that will start and run fine with the lights off & no battery.
But it might not run at idle with the lights on & no battery.

On our GT250 cafe build we used a modern Tympanium rectifier/regulator & a small AGM battery. The battery is in the seat tail bump. The rectifier/regulator is above the carbs & is mounted via the gas tank mounting bolt.
ImageCafe-GT250-0649 by jabcb, on Flickr
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
zk0ot
On the main road
Posts: 152
Joined: Mon Jul 16, 2012 11:19 am
Country: usa
Suzuki 2-Strokes: 1
Location: S.E. Wisconsin

Re: Gt250 running without battery.

Post by zk0ot »

Thanks.

Maybe a capacitor could suffice to keep lights on at idle.
We did the same for adding a water pump on a ped.
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jabcb
Moto GP
Posts: 4005
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: Gt250 running without battery.

Post by jabcb »

The alternator is single phase. The capacitor would smooth out the sinusoidal voltage variation, but not maintain voltage at idle.
Sitting at a stoplight at idle, the light might gradually drop the voltage to the point you don’t get an adequate spark.

The oil tank on our GT250 was custom made. Another option would be to get a custom oil tank that includes a small battery box.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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