It's Alive!

[Anonymous]

Success. My '77 GS750 runs. After fabricating a new points-to-coil wire, and gapping the points, it finally fired up. Ran a little rough at first, but smoothed out quite a bit. Maintains an idle a little above 1000 rpm....a bit erratic, but not bad. My only concern so far is a cool #2 exhaust pipe. It's hot to the touch mind you, just not as hot as the other three.

Also had some difficulty setting the timing. After gapping the breaker point for 1-4, I proceeded to attempt to set timing by loosening the three breaker plate screws, hooking a multimeter to ground, and where the coil lead and condenser lead attach to the points, and setting when the points open by checking for loss of continuity. Unfortunately, no matter where I place the plate between either extreme of adjustment, it always has continuity. Even when the points start to open. Haven't quite figured that out yet, so I just eyeballed it, and went for broke, and it runs. Just wanted to let y'all know that another GS lives once more.

Ryan
mueller@xta.com

[earlfor]

Another way of doing that is to set the 1-4 point set (left side) to a gap of .001 when the F1 mark is aligned, then rotate the crank until the F2 mark is aligned and set the 2-3 point set (right side) to .001 Then start the bike and final set the points to the marks using a timing light. Works for me every time. :-) MUCH easier. :-) :-)

Earl

[Anonymous]

question....

Ok. Makes sense. So set the gap on full open, which has been done to both points, and then do as you describe. Would that cause your point gap to then be out of whack? I'm thinking if your only moving it .001 or so to set when it opens, it wouldn't, but I thought I'd ask.

As I don't have a timing light, I'm told you can set it by ear to get close. Start the bike, warm it up, and at idle, loosen the 3 screws for the breaker plate, and move it until you find what sounds like the highest/best idle and smoothest running setting. Sound good?

Thanks much for the help,

Ryan

[earlfor]

Re: question....

Ryan

Well, no, I dont set the gap at all with the points full open. The points should be breaking on the F1 and F2 marks. That is, they are going from closed to open on those marks. The important thing to consider is that the maximum gap doesnt matter.
The only consideration is when the points break/open. The crankshaft lobe the points run on is about .012 out of round, so in theory if you set the max gap to .012, then they should be zero and breaking on the F marks. My viewpoint is that with the accepted method, youre setting one measurement (maximum gap) and hoping it results in another points breaking at the F mark)
I just elimate the extra step and set the points directly. I only use .001 as a measurement because it is the thinnest feeler guage I have. You want the points set as close to .0000 as you can and still not have continuity on the F marks.

Just for fun, if you set your points this way (.001 on the F marks) and then go back and check gap at maximum point gap, you will find the gap to be between .011 and .016 which is about what the books say. With the book method, there is a possibility of as much as a 5 thousandths error. With my method, the greatest error possible is .001.

I would not do the "ear" method without a lot of experience with the sound as it is almost certain you will end up with the ignition timing very advanced and there is a real risk of blowing a hole in a piston and overstressing internal engine parts. The highest idle and smoothest running will be too much advance for ignition timing at idle. A timing light is a must if you really want to be accurate. JC Whitney sells timing lights very cheaply and you only need the plainest, most simple model available. I think I only paid about $15 for mine. Its worthwhile to get one. :-)

Earl

Ok. Makes sense. So set the gap on full open, which has been done to both points, and then do as you describe. Would that cause your point gap to then be out of whack? I'm thinking if your only moving it .001 or so to set when it opens, it wouldn't, but I thought I'd ask.

As I don't have a timing light, I'm told you can set it by ear to get close. Start the bike, warm it up, and at idle, loosen the 3 screws for the breaker plate, and move it until you find what sounds like the highest/best idle and smoothest running setting. Sound good?

Thanks much for the help,

Ryan