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Discussion Starter #1 (Edited)
A strange problem has occured on my Suzuki 1972 model T250

Motor is running perfect, until I turn on any electrical switch such as mainlight, signal lights or any switch.

I have checked the charging, and the battery is fully charged all the time, but when I measure charging voltage from regulator, it is a bit high and turns higher when RMP on the engine increase.

My thought is that the recitifier may be damaged and need to be changed.

Question is: is that the reason the engine turns off when electrical switches are connected?

Any tip, help or ideas are very welcome.

I live in Norway, and the bike is a 1972 or 1973 model.

Thanks for any replies.

Rune
 

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It's possible that there is a short in the electrical system that is drawing too much power for the ignition system to fire properly.

It could also be that the charging system is too weak to produce enough voltage to run both the ignition and lights.

How much voltage are you getting at the battery with the engine running at about 3000 RPM?
 

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Discussion Starter #3
Thanks for replying.

I used a voltmeter to check, and it seems like the voltage are increasing rapidly at the same time as the RPM increase.

Its way over 20 volts after 2-3000 RPM

Short is a good suggestion, but probably very hard to find.

Thanks
Rune
 

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If you are getting 20 volts at the battery, the regulator is shot. It should be just over 14 maximum. I'm surprised the fuses haven't popped or wiring burn up!
 

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Discussion Starter #5
I agree. Thats a good theory.

But can this also be connected to tha fact that engine stops when some of the lightswitches are turned on?
 

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Discussion Starter #7
Changed recitifier / same problem

It did not help much to change the rectifier, except from engine was running a bit more smoothly afterwards.

There is still a problem in the electrical system, voltage is not distributed correctly and gives no power to lights - and when turning on lights the engine stops.

I removed the headlight bulb and then the engine does not stop when I turn on the switch.
 

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Discussion Starter #9 (Edited)
Hi Mikko.

Hope we can find out of this together. Where are you from? Country?

I have no idea at the moment, but I think the key for my part is to find out why the engine does not stop when lightbulb is removed, and then stops when put back in place.

Seemes to be some kind of 'short-circuit'. I probably have to change the turn-signal relay as well, since its probably broken due to the damaged rectifier.

What kind of bike do you have? Have you changed anything on your bike? How will you describe the problem more accurate?

If I get the turn-signals working, I will concider mounting new wires to the front light, and put on an on/off switch just to be able to run it. In Norway it is prohibited driving without frontlight, even in daytime.

Rune
 

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Same bike

I am from Finland.

I have the same bike T250J -72.

My problem is not all the time and it seems to be related to Voltage regulator(rectifier). I had only 8 volts at 3000 rpm going to the battery. I did mesure the OHM of the Silicon Rectifier and one of four was dead. Now I am butting all together to see how it works now. At least the voltage at 3000 rpm was now 14-16 volts.

I will test this change later today.

Mikko
 

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Discussion Starter #11
The T250 was delivered in two versions...

Models delivered to France and Switzerland had a voltage regulator in addition to rectifier.

Keep us updated

Rune
 

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Few run any all works at the moment. Still have to make more testing to be sure. It seems that in my case the engine stopped cause the voltage was too low to support engine, lights and turn signals.

At least it for sure that the Rectifier was broken.

Mikko
 

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Few run any all works at the moment. Still have to make more testing to be sure. It seems that in my case the engine stopped cause the voltage was too low to support engine, lights and turn signals.

At least it for sure that the Rectifier was broken.

Mikko
One odd thing happens now. Before these repairs the High Beam indicator did not work at all on the speedometer. Now it works but it has a twist. When you have driven some minutes it begins to light even with short beams ??. Too musch power(voltage) have to look in to that.

Mikko
 

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Discussion Starter #14
Is that the red light marked B?

Its the same here... turns on and off occasionaly. Depends on what position the lampswitches are.

There is another lamp too.. orange one.. not sure what that is... even that is turning on and off some times.

I have now a theory about the handleswitch that controls the headlight, turnsignal and horn... I am pretty sure there might some short-circuit there, and I will try to find a replacement. Seems like it is easy to replace.

Rune
 

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The orange light indicator is for turning lights. As they blink so will the orange light.

I first thought that the "B" indicator was for battery but it Beam :)

So there is 3 indicators in the speedo N=Neutral gear B= Beams F= (Flickers) Turnsignals.

Mikko
 

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Discussion Starter #16
Aha... that makes sense...

Now, all the lights on my bike is working, except from the headlight (frontlight)

When I take out the light bulb, the switches functions well... everything is good - until I reinstall the fronlight bulb - then everything stops.

Strange! I have scratched my head more than one time today. :)
 

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as you have volts it has to be a short circuit. Ground line all over the bike is Black/with white traceline. Does the parking light work normaly? It should light up on the 3 step from the ignition key.

Also have you opened the ignition key body. Mine was in bad shape when i got the bike.

Also adding a extra groundline from the frame to the Black line/ with White traceline could also help.

You possibly have this wiring already. Following the lines and isolating them from the rest is the only way to find the Short.

You can find a repairbook for t250 by google "t250 wiring" The firts picture will take you to oldjapanesebikes. There Wiring diagram

Mikko
 

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Discussion Starter #18 (Edited)
The parking light does not work... thats for sure. But the breaklight, turnsignal light and the light inside the speedometer is good.

I think, as an emergency solution, that it might be possible to wire from the battery and directly to the headlamp and put a switch to that.

Then, as long as the motor is running I will have lights, and can turn it off if I want. (It is prohibited by law to drive without frontlight here in Norway)

Got a tips from another american forum, and was told there that it might be that the lamp does not get enough power, and when connected it stops the engine. That was based on the information about none of the switches fail when lightbulb is out... the only thing that stops the engine is that freaking bulb.

Probably a new round with headscratching today.
 

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Discussion Starter #19 (Edited)
Update

I disconnected the frontlight from the regular wiring, put in a new cable which I connected to the headlight, and then tried different voltage sources into it.

1. Connected it to the battery
Light functions very well, but on max light of course, and I would have to mount a seperate switch for this solution.

2. Connected it to the red cable coming from the alternator
Light was weak on low RPM and increased when RPM was going up. At the same time the B-lamp/indicator was on all the time.

3. Connected it to the output from the rectifier (red/green cable)
Then engine stopped as usual.

Perhaps the theory about frontlight does not get enough power is true? Seems like that might be the case - I am not sure about short-circuit anymore.

Question in thas case is: Why does it not get enough voltage, and makes the engine stop?

I just tested the voltage from the alternator, and it gives about 13,5 volts on RPM 2-3000, and increases to about 16-17 volts when RPM goes up to 6000.
 

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Discussion Starter #20
Good golly miss molly

Now it works fine. I got a tips from a guy in USA at Oregon Motorcycle parts and he suggested the following:

Put a new wire in from green / red cable from rectifier, and connect that to the green / white cable that is seen in the switchpanel.

I found the green / white cable in the frontlight house, and put a wire between the two points - and now everything works as a clock.

Lights, horn everything. :)

Seems like the green / white cable shall give som extra transportation of voltage to the switch and lights, and obviously this connection have been broken or at least bad.

Will put in cables and put the bike together, and celebrate with a ride in the nice weather.

:)
 
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