GT550 budget build

[pearljam724]

Couldn't agree more. Also, double check the little ground wire that attaches to the battery box and frame. Make sure it is secured tight with clean eyelets, washers, bolt and contact surface. That ground wire needs to be free of oxidation. Also double check the points gap, condition, cleaned, etc.

[Suzukidave]

I was looking for the post about it but the plug caps can be disassembled , if you look inside where they fit over the spark plug you should see slots where you can use a screw driver to unscrew them . Watch out as there are small parts inside , clean up the parts inside and reassemble and see if that helps .

[Cragdog]

Went and bought new spark plug caps. I trimmed a bit off the end of each lead to expose some clean wires and rigged em all up.



Hasn't seemed to make any difference though, I'm still only getting the left cylinder to fire.

[jabcb]

For a quick test of the coils, run temporary wires at points to change which coil connects to each of the points. Switch plug wires around accordingly. If its the coils a different cylinder will fire.

[pearljam724]

You're gonna waste a lot of time and money if you don't run all the tests on the battery. Have you done that ?

[Cragdog]

I can't run a load test with this bike because I can't get it to run properly enough to test the battery at higher rpms. I have used this battery on my friends xs650 and his bike was running fine with this battery so I don't know. The voltage is at 12.7 right now with ignition off, and 12.1 with ignition on. I don't understand how the battery could be causing certain cylinders to drop however, if there is a charging system on this bike, why wouldn't the alternator be charging the battery when running thus supplying the needed voltage to insure all three cylinders are firing?

[Cragdog]

I mean isn't that the purpose of a charging system? My brothers bike has a dead battery, but still runs if you simply kick it over. Why wouldn't the same be for this bike?

Nonetheless, I guess my next step should be to take the battery out for a load test and see what the results are.

[Cragdog]

Couldn't agree more. Also, double check the little ground wire that attaches to the battery box and frame. Make sure it is secured tight with clean eyelets, washers, bolt and contact surface. That ground wire needs to be free of oxidation. Also double check the points gap, condition, cleaned, etc.

Are you able to take a picture of this ground wire? This is something I might be missing.

[Suzukidave]

Your timing light can be used as a ignition firing tester , attach it up like you are going to test timing and crank the engine , if the coil is firing the timing light will flash . If its not flashing i would use your volt meter to test the orange wires where they go to the coils , with the ignition on you should be getting around 12 volts .

[Cragdog]

I used my voltmeter and each spark plug wire was getting 10.1 volts, my battery is getting tired from so many failed attempts to start so it is now down to 11.9 volts. But if I am getting voltage at each coil then why wouldn't it be getting spark?

[Suzukidave]

Where you need to test voltage is at the wiring harness connection to the coils .. the orange wires as the are the + connection when the key is on . while testing your bike you can leave the charger hooked up , just disconnect when the engine is running . When you are cranking the engine you can put several fingers over the mouth of the carb , you should feel a equal draw .. this can also be done when the bike starts but not on one cylinder , put several fingers over the carb mouth and it will draw extra fuel and may start running if you are getting spark .

[Suzukidave]

Try the timing light test i suggested on each coil wire while cranking the engine .. getting no flash .. you are getting no spark

[Cragdog]

Where you need to test voltage is at the wiring harness connection to the coils .. the orange wires as the are the + connection when the key is on . while testing your bike you can leave the charger hooked up , just disconnect when the engine is running .

Okay, I did this at the harness and got the same reading 10.1 volts for each orange wire. Battery is still at 11.9.

. When you are cranking the engine you can put several fingers over the mouth of the carb , you should feel a equal draw .. this can also be done when the bike starts but not on one cylinder , put several fingers over the carb mouth and it will draw extra fuel and may start running if you are getting spark .

I might need more explanation on this one.. Do you mean remove the air filters and use my fingers to block passage at the intake?

Try the timing light test i suggested on each coil wire while cranking the engine .. getting no flash .. you are getting no spark

Did this and I get light when I connect the test light to the orange wires at the harness, but not when I connect them to the spark plug wires.

[Coyote]

I mean isn't that the purpose of a charging system? My brothers bike has a dead battery, but still runs if you simply kick it over. Why wouldn't the same be for this bike?

Your brother's bike has a magneto ignition. Those type of systems don't require an external power source to start and run. These GT's and most other early 2 strokes don't have magnetos. This is known as a battery excited ignition on our bikes. They will not start and run without a good hot battery. With a low or dead battery, you could kick it till the world looks level and it still won't start.

[Cragdog]

I mean isn't that the purpose of a charging system? My brothers bike has a dead battery, but still runs if you simply kick it over. Why wouldn't the same be for this bike?

Your brother's bike has a magneto ignition. Those type of systems don't require an external power source to start and run. These GT's and most other early 2 strokes don't have magnetos. This is known as a battery excited ignition on our bikes. They will not start and run without a good hot battery. With a low or dead battery, you could kick it till the world looks level and it still won't start.

So is a magneto different than the rotor(flywheel) attached to the crankshaft apart of the alternator system? Thanks coyote, this has been a learning experience for me. I really appreciate all the knowledge you guys have imparted my way. Hopefully I will have something to show for it in 2014.