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Discussion Starter #1
Hi all, Just a shout out to see if some of you have experienced these issues...a slow moving tach(until it warms up) is anything serviceable? A battery/charging system issue....this is a 1973 xl175 and it will not start without a battery...once started it barely runs the electrics...ie put on left blinker the bike shorts out...is there a way to test the charging system/magneto? When running its only at 6 volts at the battery....
 

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You only have a few possible issues.

1) That should probably be a 12 volt battery, in which case at 6 volts I doubt it is even worth charging.

2) You are using a 6 volt battery when it should be a 12 volt

3) Wires arching out or grounding out due to damage

You should be able to determine the cause by testing the battery outside of the bike. If the battery still reads 6volts, the battery is probably bricked (if it is technically a 12V batt). If, though, your battery happened to be fully charged outside of the bike (12v), then there is a chance that the low voltage reading is because an arch is drawing off of the battery.

If you know you have the correct battery, and you know its charge outside of the bike, you should be able to test the bikes alternator by testing the battery throughout ignition onto run. So if it is 11.8 volts sitting, and then jumps to 12-13 volts running, then the bikes alternator is working.
 

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The 73 xl175 should require a 6v battery. I would suggest a full battery test. Voltage test standing alone, voltage test under load (while starting), and voltage test while running (charging).
 

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Your six volt bike may very well have 12 volt lighting installed because the previous owner did not know that he had to buy six volt bulbs. This includes the flasher relay for the turn signals. Been there done that with a 1972 cb100. The bulbs are marked as to voltage. Look for them at NAPA or online

If your digital multimeter shows just six volts,that battery is dead for all practical purposes Just as a 12 volt battery will show 12.6 or 12.7 when fully charged, a six volt has to be about 6.4 or so to be charged,and that is not counting the load test.
 

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Discussion Starter #5
Hi, Yes the system calls for a 6 volt battery...I have had the bike for 10 years..previous owner was original.You have to replace the battery every other year as when it gets low the bike does not run right. I think all the bulbs are 6 volt but I will check that and make sure all other components are 6 volt. What should the proper outputs be..battery at rest, battery when running? How do I test the output of the magneto?
 

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Xl175

With the battery installed check the volts. Should be about 6.4 as Slumlord said. Use a multi meter. red to pos, black to neg.
Start the engine, with a reasonable amount of revs the volts should go up, 6.75 or maybe 7 with more revs. If the volts stay the same, the battery is not being charged, and that could be a few things wrong.

Unkle Crusty*
 

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Discussion Starter #7
Unkle, Thanks, I will test...but I feel as long as I have owned it the charging system has been marginal....what are the next steps?
 

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Xl175

I have not touched an XL175 since I sold them in the seventies. The seal at the clutch push rod would leak on the early models, and the gas went flat in the carburetor. And some were ugly orange.

Slumlord is more up to speed with them now. But on one end of the crank will be a charging system, and downstream will be an electric device to control it.
First I would check all the wyres connecting the pieces. Clean, bright and tight, is a motto for old tractors. Check inside the connecting plugs. Many ohms can be lost with all the different types of connections.

Unkle Crusty*
 

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Discussion Starter #9
also all the bulbs are stanley t1129 or 1129 nothing on them about voltage...seen to be 6 volts....
 
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