ninjette.org - View Single Post - What Did You Do to Your Ninjette Today ??

Ghostt · February 3rd, 2018, 04:30 PM

Quote:

Originally Posted by choneofakind

Fired it up and rode it finally! @genosr1 it runs like a bat out of heck.

Some new carb gaskets, a little exhaust RTV, and a new piece of fuel hose means she stopped leaking finally.

Jetting is close for now, but will need some electrical help to get it fine tuned.
Newgen engine, 2mm bore and high compression pistons, opened up intake on pregen airbox, new WIX spongey filter.
38 idle jets,
2.5 turns idle screw
110 main jet
3 washers on the needles.

Only problem is the pregen spark plug boots don't seem to play nice with the newgen head. #2 cylinder is randomly not firing. It's okay above 5,000 rpm, but under that it dies. And this engine really doesn't like starting on one spark... Then I can reach down under the tank, click the boot into place on the plug, and she roars back to life easy as pie.

@Ghostt, I remember you had a write up somewhere for taking apart/cleaning the spark plug boots and ignition coils. Think I could frankenstein a newgen plug boot onto a pregen coil? I like the mounting I have now but I want the boots to play nice with the newgen head. Got a link handy for that cleaning/PM DIY you put together, pretty please?

No problem, but I'd go with the CoPs conversation as I've done. They offer hotter spark, which allows you to open the spark plug gap, less things to wrong too.

Quote:

Even bad plugs should do something, unless they are totally shot.

Did you renew the HT leads, and disassemble the caps?

Make sure you disassemble the caps, and clean them, and yes the caps get cruddy.

Here my write-up,

Quote:

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.

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?

There's the write-up on the caps