NC29 Jet kit

[Drunkn Munky]

I got this 2nd hand jet kit but am unsure on what some of the parts are for, it includes the following

4 x Slide springs
2 x 112.5 main jets
2 x 115 main jets
4 x 112 dyno jet mains
4 x J4HA neddles
4 x 0.5mm neddle washers
2.5mm drill bit
5/32 dril bit ????
4 x nylon washers ????
Metal bar ????
A screw ????

jet kit.jpg

Any ideas?

[Yakama]

I think that is a dynojet kit, here is the instructions:

[Drunkn Munky]

The dynojet kit has adjustable neddle tho, these are just normal neddles. Is it common to drill the slides to 2.5mm and fit extra washers for a aftermarket system?

[Yakama]

Is it possible they are standard needles then? But the rest of the kit looks just like the dynojet kit I have

[cajun]

That is a stock kit after installing the DJ kit.

[Drunkn Munky]

There not stock needles, well there not the same as i have in various other carbs anyway

[Cammo]

Looks like Parus has posted some info about them here (about half way down below the pics of the dismantled carbs):

http://moto.kiev.ua/journals/1246794261819

[cajun]

The metal bar is to install the needle shrouds into the emultion tubes, given the spring spacing the springs look stock. The smaller drill bit is usually to drill slides. the bigger usually to drill the tip of a plug over the air mixture screw. Then you take the screw and use it to pull the plug out.

Compare it to the stock needle length. I would say it's either longer or shorter. Maybe look into which needles came in a CBR600 or 900.

[Drunkn Munky]

After a bit of digging it seems the kit is from a company called sigma 6, heres the instructions they sent,

1. Remove the top of the carb. Remove the slide, needle, & spacers, noting the order on schematic.
Find slide lift holes, with slide drill #37, drill the existing holes. The pic might not show the exact slide, use for reference. Do not drill the center needle hole or any new holes. Some models already have enlarged slide lift holes from the factory, if so no drilling is necessary.

2. If your model has the adjustable type needle, move e-clip one position toward pointed end. If not, install the shims below the e-clip, 2 per needle. After installing the slides in the carbs be sure to check slide movement manually, if interference use white spacers in place of silver shims. If rich through midrange, use one shim. There are variations on models, the objective is to effectively raise the needle. This can sometimes require removing spacers. Note: 1 shim is 1/2 step of a clip position.
Note: If you experience fuel problems under 4000 rpm that the needle can’t fix then try adjusting the float level. If you feel it is too rich then lower the fuel level. If you feel it is too lean then raise the fuel level.

3. Remove the stock a main jet and replace with the 112.5 main jets on outer two cylinders #1 & #4. Use 115 main jets provided on inner two cylinders #2 & #3.

4. On the schematic, locate the mixture screw. If a plug is covering it, use the #5/32 drill to drill it out, but be careful to pull back on drill just as you break through as to not damage the mixture screw directly underneath. Once through, use the removal screw to pull the plug out. Lightly screw in the mixture screw clockwise until seated with very light tension, making sure not to damage the pointed end of mixture screw, then back out 2.5 turns, or best idle.
Tip: To keep from drilling too far into the plug, wrap electrical tape around your drill bit several times about 3/16" from the tip. This will create a stop to keep the bit from drilling too deep. (Not all will have a plug.) If it is a "D" type screw, use D Tool, if slot type, use screw driver.
NOTE: We recommend placing an inline fuel filter between fuel tank and carburetor, and using a high flow aftermarket air filter with this kit.

Clip Slide Springs:
If your bike has lazy throttle response due to heavy slide springs that regulate the vacuum pistons (carburetor slides).
• By clipping the springs to the desired tension, throttle response will become instantaneous and the delay on full throttle shifts will be eliminated. The result is a much more responsive engine. Using this spring mod may adversely affect the low speed drivability.
• By enlarging or adding the slide's air displacement holes, you will be allowing them to lift and return quickly, to match the new spring tension, and provide the desired improved response.
Start with 1 loop (1/8 inch). The benefit is even more snap response. The downside is that full throttle openings from low rpm (~2200 rpm or so) will be much softer. This is an optional step and is a matter of preference. The springs can be removed and more clipped later without pulling the carbs if not sure how much to clip

[cajun]

Ahhhhhhhh........ The good ole 6 sigma jet kit. From the US where we have all of about 10 NC29's in the whole country. I would keep the needles as spares but wouldn't trust their directions. They have basically nothing to base it on except what they have copied.