I bought a real nice survivor 1975 Yamaha DT125 12 volt style USA . I noticed the point and all componets had light rust on it so me and and my son gently started cleaning the area will supply pictures . I can get a arc with the screw driver but not between the pointrs I'm assuming they are dirty and shorting out. I have one on order . I believe the gap to be .016 gap on points someoone said a dollar bill thickness.. Any help appreciated I wonder if you can remove the bolt and remove the weights on the advance system. I can't find or see the high point on the shaft that the points ride on and advice there. Ordered a book still waiting on it. Thanks Someone said Capt Dave was good with Yamaha DT125s

Hi Patroll330.
The bike looks good. You've done okay there.
You can download a free manual of this site in the tech section . That might give you some insight.
Also, the gap is set by finding the correct timing, then set the points . and i think on your model you have to have the advance open too.
You can buy feeler blades for not much more than that dollar bill you mention for checking the gap too.
I'd be cleaning all the contacts for a start. don't forget to wipe the surface of your points as they come with a protective coating on them.
Regards shyted.

I can see one brush is about bottomed out on the spring so chances are 'that' & all the brushes are worn out. That won't stop it running with a good battery although might have to kick start it. So don't worry 'yet'. Necessary for the charging side which in the end leads back to keeping the battery up for a spark. She'll run for ages on the big good battery, just don't go too far from home, or as we say--stay on the bus route!!.
I know it looks pretty bad but if it ran when parked then chances are just a light scratch of the points with emery paper then wet & dry paper will have it running. Providing points are free on their pivot. Plus advance free but should still run regardless but not very well if retarded.& not throwing out. Timing will be near enough as ran once before you bought it. Just my warped ideas but like to keep it simple until more indepth required. Here's a link to a manual that "shyted" mentioned above. Its as near as seems to be there but go down to chapter No7 for 12 volt electrics. I had a bit of fun trying to get into it but just my computer skill or lack of lol. So--as shyted said, clean points first.
www.yamaha-enduros.com/index.php/service...a-b-c-service-manual

The site says page isn't found 404 , Is there another way to find the manual ? I'm not messing with the timing buy don't you have to have a special tool ?

If you're messing with the points, you're messing with the timing. 

Go to Tech Library link at top of most pages and go to the Service Manual section to find your manual.

Hey Patrol , are you having the same problem with the Tech Library as I am?
You try to just " view "  and get page not found 404.
Try and download it, see if that works !?!

I know my points are real dirty I can open them and I get a arc but nothing across the point only on the side. Its hard to see the high point of the points cam that has the high point . Can you remove the one bolt and remove the advance portion so you can veiw the points? Whats your best recommendation on the point changeout on my DT125B  ? My electric start only clicks no movement. This bike has less than 3,000 miles but you can tell the points screw has been turned some wish I could replace that screw that holds and adjust the points.

I got the manual to work the next time I tried .Thanks

Got it thanks it started working . Thanks

Finally able to download the manual . Thanks for the information .