Point Setting

[Anonymous]

This is the bike, a 1979 GS750e 18,000 miles. 4-1 megaphone exhaust unknown size jets. Very fast and powerfull when working right.

This is the problem. Every two hundred miles or so I had to clean the #2-3 plugs to keep performance up. It ran great after that. Last week I took it on a 60 mile trip in the 70 degree weather. Three miles from home I lost all kinds of power. Making it home I cleaned the plugs and learned that they weren't the problem. The bike was (is) falling flat on it's face when I twist the throttle. It sounds smooth when idling though. No backfiring or popping sounds. I was suspicious of the coil as I learned that those two cylinders (2-3) wouldn't fire. A friend gave me an old coil to try on my bike, correct model and everything. The plugs still wouldn't fire. I checked the power to the coils and learned that the left coil, when sitting on it (2-3) wasn't grounded. I located a wire under my seat (Black and yellow) that was broken from the seat closing on it. I thought that the broken wire may have been my problem as an intermittent fault. I fixed the ground. The plugs would still not fire. Thinking that the new coil was defective, I placed the original coil back in. You guessed it, no fire in 2&3. Then I tried to mess with my points and I think I really screwed things up. Now it starts easily, sounds good under 1500rpm but when its put under any kind of load, it spits sputters and shuts off. Help!!!

My questions follow;
1/ Should I have power going to the coil when the ignition is on and not running?
2/ Is one wire hot and one a ground?
3/ What is the easiest way for someone who knows nothing about points, to set them?
4/ Could the points be the problem.
5/ Could there be juice to the coil, but not to the plugs due to the points?

I don't mind putting time and some money into the bike, I just wish I knew I that I was heading in the right direction.

Thanks in advance for any help.
Dave W.

[Bill + Karen]

I am betting it is the condenser, I had a Ford Van that would eat them. Those were the symptoms give it gas and it would puke. Hope this helps, Bill

[earlfor]

Re: Point Setting

Well first, I ride a 79 GS 750 E with points ignition system.

Sitting on the bike, the coil on the left fires cylinders 1 and 4. The coil on the right is cylinders 2 and 3. Each coil will have a positive power feed/wire that is orange and white striped. This wire on each coil connects to the + terminal on the coil. The positive terminal is 12 volts positive input to the coil. The terminals marked negative (-) on your coils are 12 volts POSITIVE OUTPUT from the coil. The positive output wire (marked -) on the left coil feeds the points on the left side of the ignition breaker plate. (the point set located at the 9 oclock position) The wire will be either black or white. Just be sure you have the same color feeding off the left coil negative - terminal that is going to the left point set.
The right coil output terminal (-) will have the opposite color. (if right coil is black then left coil will be white.

Once youre sure the wiring is correct......

Loosen the 3 screws holding down the breaker plate (theyre located at 12, 4 and 8 0clock positions) The 12 oclock screw is in a slot. Rotate the breaker plate to center the screw in the slot. Tighten down all three screws. Using a 19 mm wrench, rotate the crankshaft clockwise using the LARGE nut on the crankshaft until the pointset on the left is at its greatest gap. Loosen the screw holding the contact point set allowing point adjustment. Set the gap to 14 thousandths. Tighten screws on pointset. Rotate crank until the pointset on the right is at its widest gap. Loosen screws and set right pointset to 14 thou. Lock screws back down.

This should get you running. Precise timing can then be done with a timing light utilizing the first set of "F" marks for low rpm non advance timing or the 2nd set of "F" marks for checking full advance.

Earl

This is the bike, a 1979 GS750e 18,000 miles. 4-1 megaphone exhaust unknown size jets. Very fast and powerfull when working right.

This is the problem. Every two hundred miles or so I had to clean the #2-3 plugs to keep performance up. It ran great after that. Last week I took it on a 60 mile trip in the 70 degree weather. Three miles from home I lost all kinds of power. Making it home I cleaned the plugs and learned that they weren't the problem. The bike was (is) falling flat on it's face when I twist the throttle. It sounds smooth when idling though. No backfiring or popping sounds. I was suspicious of the coil as I learned that those two cylinders (2-3) wouldn't fire. A friend gave me an old coil to try on my bike, correct model and everything. The plugs still wouldn't fire. I checked the power to the coils and learned that the left coil, when sitting on it (2-3) wasn't grounded. I located a wire under my seat (Black and yellow) that was broken from the seat closing on it. I thought that the broken wire may have been my problem as an intermittent fault. I fixed the ground. The plugs would still not fire. Thinking that the new coil was defective, I placed the original coil back in. You guessed it, no fire in 2&3. Then I tried to mess with my points and I think I really screwed things up. Now it starts easily, sounds good under 1500rpm but when its put under any kind of load, it spits sputters and shuts off. Help!!!

My questions follow;
1/ Should I have power going to the coil when the ignition is on and not running?
2/ Is one wire hot and one a ground?
3/ What is the easiest way for someone who knows nothing about points, to set them?
4/ Could the points be the problem.
5/ Could there be juice to the coil, but not to the plugs due to the points?

I don't mind putting time and some money into the bike, I just wish I knew I that I was heading in the right direction.

Thanks in advance for any help.
Dave W.

[earlfor]

Hmmm, come to think of it Bill, youre probably right. :-)
Dang condenser.

Earl

I am betting it is the condenser, I had a Ford Van that would eat them. Those were the symptoms give it gas and it would puke. Hope this helps, Bill

[SqDancerLynn1]

Also if you are checking the voltage, Check it with the points open, if they are closed you will not get the correct reading

[earlfor]

Re: Point Setting

My questions follow;
1/ Should I have power going to the coil when the ignition is on and not running?

<<<<<< Yes, anytime the key/ignition is switched on, there is power going to the coils. Engine running or not running makes no difference.


2/ Is one wire hot and one a ground?

<<<<<< NO.....both are hot + + is 12v positive input and - is 12 volts positive output.

3/ What is the easiest way for someone who knows nothing about points, to set them?

<<< explained that in previous post.

4/ Could the points be the problem.

<<<No, not if only one cylinder is misfiring. A bad pointset would cause the loss of two cylinders. The points can be incorrectly gapped resulting in the ignition timing being wrong and consequently, the engine may not run even though there is spark.

5/ Could there be juice to the coil, but not to the plugs due to the points?

<<<<<Yes. the points could be grounded out, or the insulator on the pointset worn, or the condenser could be bad or the points could be so pitted/corroded as to not fire the plugs.

Earl

I don't mind putting time and some money into the bike, I just wish I knew I that I was heading in the right direction.

Thanks in advance for any help.
Dave W.

[Anonymous]

success

Thanks for the tips. I took the advice of both Earlfor and Bill+Karen. I followed your instructions to the letter Earlfor and replaced the condensors as advised by Bill +Karen. Once again the machine runs great. The first few seconds were a little questionable until it blew out all of the old fuel that had built up in the 2-3 chambers. It looked like a low flying crop duster for about ten seconds.

For some reason my instrument lights went out, but I think I can figure that one out by myself. I also have a slight popping when I throttle at low(2000-3000) rpms and then back off. Not a loud backfire, but definitely there.

Again Thanks for the help,
Dave W.
Mount Joy, Pa.

[earlfor]

Re: success

Glad to know youre up and running again. :-) :-)
On your popping at 2 or 3thou rpm, thats usually a sign of a lean condition.
However, if it is very slight and the plugs are burning a tan, color, I would leave it alone. As long as the center ceramic on the plugs isnt white or ash white, you should be fine.

Earl


[quote="herco"]

Thanks for the tips. Once again the machine runs great.