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Re: [Roadsters] Electrical question

Subject: Re: [Roadsters] Electrical question
From: Mark Miller via Datsun-roadsters <>
Date: Tue, 27 Oct 2020 12:19:59 -0700
References: <>
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I concur and would start with the charging circuit: betting on a bad 
voltage regulator.  And if you don't have a test light a meter set to 
current (mA  DC) is a nice tool as well (especially if there is more 
than one problem).


Mark Miller   707-490-5834

On 10/27/2020 11:00 AM, wrote:
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> Maybe a bit more difficult on a murdercicle but here's how I do it on a car. 
> Charge the battery so it's at least 1/2 charged, then take the negative cable 
> off the battery. Put a test light between the battery post and the cable end. 
> If there is a drain, the light will light. Now start removing electrical 
> things until the light goes out. (On a car I pull fuses one at a time.) When 
> the light is out you know which circuit to tackle. That might be enough to 
> get you started.
> Stan, who has 2 Yamahas under the deck; wife's DT125 and my DT250
> Not a roadster-specific question, but related to vintage vehicles (my '72 
> Yamaha): Any tips on tracking down the cause of a battery draining down near 
> flat after a couple of days of sitting? New(ish) wet-cell battery, just 
> topped up the acid this Friday, charged it up. On Saturday the bike started, 
> ran fine (after I cleaned a couple of fouled spark plugs ? two-strokes, you 
> gotta love 'em), but went to try it again this evening and it barely lights 
> the neutral light.
> Gary McCormick
> '70 Datsun Roadster
> SRL311-13291
> San Jose, CA[Roadsters] Electrical question
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