coil problem i think

yes just recently restored a 77 kz1000 ltd upon putting it to gether im not reallly gettting much spark so it seems there is a occsiaonall zap of spark bur nothing like zap zap zap zap its like zap ...................zap what u guys think could be wrong . do the coils ground off the frame or do they ground by wires i have all the wires plugged in towhere they were when i took it apart. anyidea s

hmeric7 wrote:

yes just recently restored a 77 kz1000 ltd upon putting it to gether im not reallly gettting much spark so it seems there is a occsiaonall zap of spark bur nothing like zap zap zap zap its like zap ...................zap what u guys think could be wrong . do the coils ground off the frame or do they ground by wires i have all the wires plugged in towhere they were when i took it apart. anyidea s

Coils aren't grounded, and would function the same suspended in mid-air so long as small wires are connected to primary terminals and plug wires connected to plugs.

Have oem points been replaced with electronic ignition?

Good Luck!

i know it has a gerex ignition box on it which worked great when i took the bike apart and the bike has only been apart for about a month and i ve got most of it back together and just trying to get it going again. i h ad some spark but i dont know if the battery was to week when it was cranking but i doubt it. anyways where does the engine gorund on these bikes if anyone knows. i know that there is a ground on the kick start side that runs up to the battery is that the only one.

Make sure your battery to engine ground is clean and solid. Also check that all your plugs are good and clean, and all the wire connections to the coils.

Just make sure everything is prestine clean! :laugh:

good luck!

well i got her running i think the problem wwas that when i painted the frame and coils i put the wires on the wrong coil then onto the wrong plugs so i think i has the coil that was supposed to be plug 2 and 3 supplying plugs 1 and 4 if u understand.lol does anyone know which coil powers the 1 and 4 cylinder and which one powers the 2 and 3 . if u could just tell me the colors of the wires which hook up to the coil i can get it from there. Also isdoes it matter whick tit u plug the wire in as long as its on the right coil.

hmeric7 wrote:

well i got her running i think the problem wwas that when i painted the frame and coils i put the wires on the wrong coil then onto the wrong plugs so i think i has the coil that was supposed to be plug 2 and 3 supplying plugs 1 and 4 if u understand.lol does anyone know which coil powers the 1 and 4 cylinder and which one powers the 2 and 3 . if u could just tell me the colors of the wires which hook up to the coil i can get it from there. Also isdoes it matter whick tit u plug the wire in as long as its on the right coil.

Coil on left (shift lever side of bike) fires the two outside spark plugs #1 (far left) and #4 (far right). "Tit" selection doesn't matter. A small wire (often red/yellow, or sometimes solid red) feeds battery positive voltage to one primary terminal on the coil. Another small wire (often black) connects to the other primary terminal on the coil. Either small wire to either primary terminal on the coil is okay.

Coil on right (brake lever side of bike) fires the two inside spark plugs #2 and #3. "Tit" selection doesn't matter. A small wire (often red/yellow, or sometimes solid red) feeds battery positive voltage to one primary terminal on the coil. Another small wire (often green) connects to the other primary terminal on the coil. Either small wire to either primary terminal on the coil is okay.

Good Luck!

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Coils aren't grounded, and would function the same suspended in mid-air so long as small wires are connected to primary terminals and plug wires connected to plugs.

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Would they really work in mid air? The coils send a very high voltage,(in the order of 40,000V or so) to the plug tips, and the spark jump thru the gap because they see ground at the other end of the gap. The plug bodies are the path to ground thru the engine block, therefore the plug bodies should be making contact with ground, isn't it?

hugo wrote:

Coils aren't grounded, and would function the same suspended in mid-air so long as small wires are connected to primary terminals and plug wires connected to plugs.

Would they really work in mid air? The coils send a very high voltage,(in the order of 40,000V or so) to the plug tips, and the spark jump thru the gap because they see ground at the other end of the gap. The plug bodies are the path to ground thru the engine block, therefore the plug bodies should be making contact with ground, isn't it?

The spark path is through the engine yes, but unlike classic cars, the spark path does not need to go to ground. The fact that the spark path goes through ground is incidental. The true high-tension path is from coil-to-plug1-to-engine-to-plug4-to-coil. The important part is that it goes from the coil back to the coil. The engine is just used as a piece of metal to complete the path. If you hold the coil in mid air, un-screw the plugs and hold them in air touching each other, it will still spark (leaving all wires connected, of course).

In classic cars, the true high-tension path is coil-to-plug-to-engine-to-coil. Here the engine is used as a piec of metal to complete the path from the spark plugs back to the coil. If either a plug or the coil is removed from the engine and held in mid air, no spark.

Here's one way to think of what happens in the secondary loop when the coil fires.



Good Luck!