Somethings WRONG!

Okay guys, guess I spoke too soon... Been running it all day. Then I get about a mile from home. And boom, starts sputtering again. Had to kill it on the side of the road, let it sit about 20 seconds, kicked it, ran fine.... This is starting to get to me...
 
Just read through the thread again, and I'm not sure if we ever found out what kind of flow you get from the fuel line when disconnected from the carb. It should flow the full diameter of the line, and freely. If you have that good flow downstream of the filters and the "T" hardware, I'd go to the floats. It really sounds like it's starving for fuel. Looked at the plugs lately for color?
 
What ignition are you using. Being a 77 it came with points. The stock points coil were not very strong. Even new replacements aren't much better. I might suggest using a better coil. Using a dual output coil with a bit more output is a good upgrade. To use one just hook both sets of points together then hook to the coil. This make the coil fire like the later TCI ignition does. Every time the pistons come up. One on compression stroke the other on exhaust. Referred to as wasted spark.
If you read through some of the ignition mod threads you will find plenty of coil options.
Leo
 
Others may disagree, but my experience with automotive coils(50's through 70's ignition systems) as far as testing is a black art, and inconclusive. The way they behave at different temperatures alone is enough to drive you nuts. One quick test- when you have the failure, put your hand on the coils- if they are really hot, that is a pretty good symptom of an internal failure. Fuel delivery issues usually manifest themselves at the top of a long hard pull, it may or may not be tied to high rpms as well, mid RPM at wide open throttle over time can certainly cause a demand that exceeds supply if there is a restriction somewhere. Keep at it- this kind of thing is similar to beating your head against a brick wall- it feels really, really good when you're done!
 
Checking the coil with an ohm meter isn't hard to do.
Unhook both the primary side wires, using a low ohm scale touch a lead to each wire. The book specs 3.9 ohms +or- 20%. That's 3.12 to 4.68.
On the secondary side unscrew the plug wire from the coil. Now look down inside where the plug wire screws in, touch one probe of the meter to the screw down in there. The other to the mount bolt of the coil, or the orange wire. book spec of 8k ohms, +or- 20%, 6.4k to 9.6k.
also check ohms from the primary side to the secondary side by checking from the primary wires to a mount bolt and where the plug wire hooks.
this test should be infinity or no continuity.
If the reading on the primary are too low it has an internal short. The same on the secondary. If you get a reading between the primary and ground, an internal short. A reading between the primary and secondary is an internal short.
Leo
 
If the bikes shuts down fast, shuts off, it might not be the fuel levels. When your bowls start to run out you will notice the loss over a few seconds or more. It if starts to run bad and you let off the throttle half way does it run better at that moment? Chopping the air should bring back your mixture and let the motor run.

If you have the points and dual coil setup that too should let the bike run but bad if a coil was dropping out. It would be a rare luck to have both go bad the same exact way and both shut off together. It is basically 2 seperate units sharing a condensor housing.
 
Yea im pretty sure its a bad coil... I left work yesterday, itbwas hard to start(usually starts first kick), and it sputtered the whole way home. I stopped felt the coils, one was warm thr other was cold. Felt the exhaust, one was blowing hot, the other cold. Im going tondisecy some shit tomorrow night and hopefully get to the bottom of it.
 
Oops I thought I did. Must have messed up some how. A coil is a step up transformer. It contains a winding with a small amount of turns around a core. This is the primary side.
Also around this core is a winding with a shoot load of turns. This is the secondary side.
When current is applied to the side with a few turns a magnetic field builds around the core. This happens when the points are closed. When the points open this magnetic field collapses very quickly. Thus rapidly collapsing magnetic field creates a current in the secondary side. With the very many more turns of wire thus side creates a lot more volts than the primary side voltage. On your stock points coils this step up is from about 14 volts to over 10,000 volts.
This high voltage is what causes the spark.
Now looking at your coil the primary windings are hooked to the to small wires hanging out of the coil. One wire goes to battery power from the engine stop switch. The other goes to the points.
The secondary is where the plug wire screws in as one end of the windings. the other end of the windings hooks to the wire that goes to the points and the mount bolts. This is a ground connection.
As the very high voltage flows out of the coil it travels down the plug wire to the plug, jumps the gap and grounds to the engine, As in all things electrical t must return to the source. It does this by traveling through the engine to the frame, from the frame back to the coil through the mounts. It partially travels through the ground wire of the coil and points.
Hope this helps.
Leo
 
On the stock coil it may have say 200 turns of wire on the primary side and around 115,000 turns on the primary side.
This steps up the voltage around 575 times.
On e higher output coil they use even more windings on the secondary side. For around 30k output it may have 500,000 turns on the secondary side to 200 turn on the primary side.
These numbers may not be exact but you get the idea. A coil can be quite the complicated device to with stand that kind of voltage and keep working as long as they do.
Leo
 
Pretty sure I found the problem, left coil for sure. But the left coil is connected to the right spark plug. Always been that way. Would this cause a problem in the future? Right coil fires left piston, left coil fires right piston.
 
As far as the left coil firing the right cylinder it means that you have the point wires switched. The only problem I could see it causing is when you are trying to time the sets of points. It would probably be best if you went ahead and put it back to original just so later you are not chasing your tail when trying to adjust your points. If you have a manual it will tell you which set of points is for which cylinder and what color wire goes to each coil.
 
The upper set of points should hook to the right coil.
Where the wires from the points plug into the wires from the coils just switch them.
Leo
 

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