I just changed the plugs on my 06 Ninja. Comments?

[NinjaFinally]

I had the tank off to clean and reconnect the pass wire that never made a good connection after I changed the LH switch block. Then I saw that I could get at the plugs, and the previous owner had given me a new set. These are what I took out - they look lean to me, and I don't know how old they are. Was careful to twist the plug boots to make a tight seal. New ones feel better, with more "pull" over the rev range.

[DannoXYZ]

Well, impossible to really tell AFR because it's average over entire lifespan. To really use plug-readings, you want to narrow operating-range to short duration and only one operating zone, WOT. So to read plugs:

1. install new plugs
2. Run bike to redline WOT
3. immediately chop throttle and hit kill-switch at same time. This stops airflow through carbs that may affect readings
4. immediately pull plugs at side of road to take reading. Too much time passing causes surface to change

It's not exact science, more like reading tea-leaves. Modern tech like wideband O2-sensors are 1000% more accurate. Will tell you data that's impossible from reading plugs, such as mixtures being too rich at WOT and too lean in mid-range. Solution is smaller main jets and shim needle 1-washer. Conclusion you'd never come to by looking at plugs.

If that's true throttle-chop plug reading you have, I'd say they're spot-on perfect, don't change anything.

What really wakes these bikes up is 3D mapping of ignition. They can really use 10-degrees more ignition advance in partial-throttle mid-range. Yet keep current amount under WOT mid-range.

[Ghostt]

Fuel additives will effect a plug read as well.

Another question is did you service the plug caps when you change your plugs? It a very overlooked service item

[Ghostt]

Here is my write-up on how to service the caps,

Short explanation: The inside of the hard plastic caps accumulate crud the can short out the spark. This can cause rough running or failure to start. Every time you do any work on the bike: remove them disassemble and clean them and renew the wires or at least the connections.

The long Explanation, Warning engineering information can cause Drowsiness.
The ancient cylinder design of the engine dictates that the spark emanate form the center of the combustion chamber. In order to get it there, the plugs had to be located down deep in a well between the cams. This well is a perfect place for dirt and moisture to accumulate. Then because there is no cooling water at this point the metal around the plug runs very hot. Surround this with the large amount of cool metal and you have a recipe for condensation. Now K did drill a drain hole between the fins to help (a little) but it often gets plugged up.

The moisture boils off the base of the plug and the vapor condenses on the cool plastic cap and the plug insulator. This moisture forms a easier path for the electrons to ground than jumping the gap at the plug to make a spark. Misfire.
This issue is right up there with Pilot jets as a cause of trouble.[/QUOTE]


Here's some pictures that might be helpful. I took these when I replaced the wires themselves, as it was a good time for a write-up, and the wires were OEM from 1998.


Wires are just 7mm copper core, with clear silicone jacket









IMPORTANT NOTICE: make sure to use a proper screwdriver, make sure it fits, as the parts are made of brass inside the spark plug caps





Important notice: the wire must be screwed on the spark plug cap, note the screw like object inside the spark plug cap?



Important notice: be careful to not loose the ferrules on the HT leads, these keep the wire from falling out of the coil. Below is an example of ferrules on a pressure fitting, looks familiar?

[Ghostt]

Also if you wish, you could update to coil on plug here's the link to another one of my write ups

https://www.ninjette.org/forums/showthread.php?t=241339

[NinjaFinally]

The plugs are of unknown vintage, it has 26K on it and I bought it 1k ago.

[ducatiman]

any bike "new to you" with no known service history ....its imperative to fully service.

Have you ever confirmed valve clearances?

[Ghostt]

Originally Posted by NinjaFinally

The plugs are of unknown vintage, it has 26K on it and I bought it 1k ago.

Judging how they look I wouldn't be surprised if they are the original plugs.

So often these bikes are abused and neglected in oh so many different ways.

Very seldomly has any service been done on these bikes, they are passed around like that girl in highschool.

Whenever you purchase a used motorcycle no matter what kind or type it is, you always go through it top to bottom because in the end it's your safety and your time and your riding enjoyment that's a stake