dual points adjustment?

[ReycleBill]

I'm reminded of a mechanic at a towing company where I once worked. I came in with one of the older wreckers and told him it needed points. He said he's get right on it. A few days later I needed that truck for an emergency call but it wouldn't start. I jerked open the hood, popped the distributor cap and the old points were still there.

After I returned from the call I stormed into my boss's office and then the 2 of us stormed into the shop. Turns out the 23 year old mechanic had never heard of points and had thought I was joking that day when I told him to put new points in the truck. The boss and I then taught him hands on how old school ignition systems worked.

That said, when it comes to modern ignition systems, that 23 year old mechanic is light years ahead of me.

 

[Tecrekka]

This to me seems the easiest, safest and most efficient way to set/test the points set up, as it allows you to take your time and not worry about turning your coils into cylindrical ashtrays!
I've never messed with a point system and have read every post and manual that I can get my hands on and still wasn't completely clear on what was going to happen. The biggest issue with me was understanding what position the cam should be in when setting the gap. After that was the slippery nature of the XS points and their tendency to shift after setting/while tightening.
I think I've got it, but have encountered some issues that are making me become concerned that I may have a more severe problem than can be remedied by adjustments.
After getting the points gapped properly, I found that my adjustments somewhat bottomed out against each other. To be more specific, I found that the only way I could get the top/right cylinder was to turn the adjustment all the way to the right, which still left the mark far to the right of TDC on the stator. As a result, I was able to turn the bottom/left cylinder to lay dead center in the F range, but can't get the bike to start. It was running, left side seemed to be fine and right was popping and bogging when I tried to give it gas. I completely went through both carbs and took some time to finally get them straight as far as proper jets and adjustments. Only after I eliminate carb issues did I begin to address timing.
When the bike was running, I adjusted the cam chain tension, but it seems to me that I may still have some play in it. While adjusting the timing, I noticed that I've probably got about 6° total of play in the cam end, which leads me to believe the cam chain may be stretched out of spec?
I've attached some pics of where my adjustment positions are as well as where I find the points opening (infinite resistance).
If anyone has some input I'd really appreciate it. Thanks.

 

[XSLeo]

The timing marks are just for timing.They don't really have much to do with setting the gap.
The lobe that opens and closes the points is a circle with part of the circle ground away to let the points close. As you turn the engine over as long as the rubbing block is up on the circle and not down on the low spot you can set the gap.
As the engine turns the points close and this lets current flow through the coil. As the engine continues to turn the points start to open when the rubbing block starts up the ramp from where the lobe is ground away to the circle. When the points open the current flow stops and the coil sparks.
Once you get the points gapped you start with the upper, right set and get the moment the points open to occur while the rotor timing mark is between the two F marks.
Once you get the upper set done you then do the time the lower set.
If you can't get the timing set with out running out of the adjustment slot you can try resetting the points .002 more or less than you had. Changing the gap changes the timing. It's been too long since I worked with points to recall if wider advances or retards the timing. Try both ways.
You might need to set the points gap a bit differently to get both set right, that's part of why the spec reads .012 to .016.
Also if you have the adjustment all the way to the end of the slot this often is a sign of the can chain being worn or off one tooth if you have replaced the chain.
Leo

 

[Tecrekka]

Well, I reset the gaps and was much more in range (retarded the timing a bit). As it turns out, they were set imporperly in the first place. Once I got the gaps right I was able to set the timing properly and she ran perfectly! What was really driving me nuts is that I started with a bike that ran rough and ended up with one with the timing set properly that didn't run at all. Noting what Pyrocentric said about the advance lobe, I reversed the coils and it started right up! Apparently it had been installed imporperly before and when I redid the wiring harness I connected them properly.

 

[gabecustom]

hey guys, i know i'm a couple years late on this feed, but thanks for the info on cleaning up the points! flipping awesome! I will replace them later, but I've got spark on the left cyl. now thanks to all the in-tell!
I like the bit about the 23 year old as well.. lol I'm 26 and have been to MMI for Yamaha and HD, didn't learn a thing about point at motorcycle school.. thanks again!

 

[ReycleBill]

I like the bit about the 23 year old as well.. lol I'm 26 and have been to MMI for Yamaha and HD, didn't learn a thing about point at motorcycle school.. thanks again!

That's why we're still hangin' 'round.