gt185 ec rebuild

[stinkwheel]

Here is a diagram of how the points should be assembled.
There is an additional insulator that you can not see in the diagram — its a small tube that covers the screw threads.

Sorry mate, lost again!! there's no yellow wire only one black from.the condenser and a white from the coil ( lhs)

[jabcb]

Just ignore the wire color in the diagram. Its an old diagram I made for a different bike.

[Coyote]

Yes, it's missing the incoming lead. That gets sandwiched with the coil wire tab.
That tiny insulator sleeve over the threads is usually lost. I've seen a few sets of points that work without that sleeve. How does that happen / work?

[jabcb]

Some bikes have condensers with only one wire — those bikes have two wires going to the points.
Others have condensers with two wires — one wire goes to the points & the other goes to the coil.

The diagram was based on a GT250. Here is an example.

[Coyote]

Never seen a setup like that, but then again I haven't fooled with a magneto ignition. I like it! Much less cluttered than messing with 6 wires (380 up GT's).

[stinkwheel]

Me again, sorry

Right, the white wire from the coil is earthing out, I disconnected it from the points and it earths out so that's the first clue. If I put the meter between the white terminal on the coil and earth it will do the same ( no surpises with the connector connected so to speak ). If I pull the connector between the coils and the main loom a. the white at the points stops earthing and b. the white at the points also stops earthing. Put it back together and the white earths out again. This a continuity test only with the ignition off.

Any suggestions on what this actually means gratefully received.

Cheers

[jabcb]

Check for resistance instead of continuity.

Prop both sets of points open with an insulator, something like a clean 3x5 card.
Do resistance checks for both sides & let us know the results.

[stinkwheel]

The white wire is reading 8.2 ohms between it and earth. Thoughts??

I will test the other connections later.

Thanks for your patience

[jabcb]

You measured coil primary resistance at about 4 ohms.

If you measure resistance between ground & the open left points when the right points are closed, then the electrical path is left points to left coil, then to right coil, then to right points, then to ground.
path resistance = 4 ohms for left coil + 4 ohms for right coil = 8 ohms

This is why suggested using an insulator to prop open both sets of points.



You can ignore this part….
Your multimeter has an internal resistance — you can touch the leads together to find out what it is.

If the readings you gave are exact, then…
Your multimeter has an internal resistance of 0.2 ohms
So your coil primary resistance = 4.2 - 0.2 = 4.0 ohms
And your measured resistance for the above = 4.0 + 4.0 + 0.2 = 8.2 ohms

This also isn’t exact because at best your readings are something like +/- 0.05 ohms

[Coyote]

I disconnected it from the points and it earths out so that's the first clue. If I put the meter between the white terminal on the coil and earth it will do the same.

It sounds to me like the white wire itself is OK. You can double check that by setting continuity and your leads on both ends of the white wire ( not hooked to anything). So the problem must be in the wires feeding the coil, or the coil itself.. I think it's time to reverse the coils and do some checking. First use the left wires on the right coil and see if the problem follows the coil (spark on left - none on right). Now use the known good coil (the right one) wire it in the left side. If you have spark, then it's not the wires leading to the coils from the harness You see what I'm getting at here? Hard to explain. Basically if the left fires using the right coil and the right doesn't fire using the left coil, you have nailed it down to the coil itself. If the right fires using the left coil, then both coils are OK.
I had a similar problem. It was early on and the point wires were were not connected to the harness (3 wires in my case). I was setting the timing using a simple battery operated lamp. Got all three timed in, but when I double checked, one of the 3 was dead. WHAT?! The lamp I use is always on and goes off when the point opens. Well this one stays on 360 crank rotation. I could see the point opening. I finally gave up figuring I was facing a real mess. About an hour later while doing other things, I noticed that 1 of the 3 point wires had drifted over and was touching the frame. That's where my continuous continuity was coming from! I moved the wire, hooked the lamp back up and everything was fine.

[stinkwheel]

OK, done the card thing and resistance doesn't register on any of the scales on the meter so I guess there's no short. I then swapped the coil wires and the good news is the fault didn't migrate so I've proved the coils are ok. 'course, the bad news is I've still no spark on the lhs.

Help!!

[jabcb]

Good, you are making progress.

With the left points closed & the right points open, check the voltage across the points for both points.
For both coils, check voltage between ground & coil primary (wire going to the points).
For both coils, check voltage across coil primary.

Repeat with left open & right closed.

[stinkwheel]

Right here goes...

Wiring back to normal......

Lhs points closed, rhs open 12volts and 12 volts respectively

lhs primary wire to earth 12v rhs primary wire to earth 12 v

across the primary 0v on both

rhs points closed lhs open 0 v and 10.3 respectively

lhs primary wire to earth 10.3v and rhs primary to earth 0.12v

across the coils lhs 0 volts and 10.3 v on the rhs

[jabcb]

With the left points closed you have very little or no current going through either coil. == > BAD

With the right points closed you have reasonably good voltage numbers. ==> OK


Check to see if the left points actually closes completely.
What gaps did to set the points to?

[stinkwheel]

points are set at 0.4mm dont know what that is in imperial