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Finally got around to jetting the carb., what a difference this makes!

When I first unpacked my cycle and put gas in it, it didn't run well at all. Hard to start, barely idled, stalled coming off idle... What a disappointing mess. But I bought the race kit which includes some new jets and adjusted it to the suggestions. As mentioned in the set up, you want the idle air screw adjusted out 2.5 to 3 turns. Set the needle on the number 4 slot, and change the main and idle jet to one of the ones included in the race kit. On with the pictures.


You start by pulling the carb and manifold off, and notice the casting flaws, these will need to be cleaned up at some time in the future (and will be a future article).


intake casting1


intake casting 2


Now to the carb. On the right side near the center is the idle speed adjustment screw. When the engine is running and gets warm, you'll want this to around 2000rpm. This was suggested to me and seems to work fine.


carb right


On the left side, not much to see or do.


carb left


On the bottom is the float bowl, and also at the top middle of this image is the idle air adjust screw. This screw gets turned in until it stops (not tight), then turn it back out about 2.5 to 3 turns. May need to adjust this more later but this is a good place to start.


carb bottom


When you remove the four screws, you will see the float, main jet, and idle jet. I changed the main to the 102.5, and the idle jet to the 22.5 from the race kit. Stock sizes were 100 and 20 respectively. Not sure it was right, won't know until I am able to run it a lot and probably not without back to back comparison.


carb jets


I didn't picture the needle, sorry. Push the needle out of the throttle slide and change the clip. I set it into the fourth from the top (moved it up one). Again, not sure this is right, but it is where I'm going to start.


Before putting everything back together, it was time to check and make sure that everything had a smooth transition from one piece to the other. The manifold to head was decent enough for now. The plastic spacer to manifold was also pretty good. But the carb to plastic spacer had a big problem. The carb is bored into an oval for the outlet, the spacer is cut for a circle, so there was a big lip that you can feel by sticking your finger inside. I bolted the plastic to the carb, and used a bent pick to scribe a line around the edge of the carb.


carb spacer 1


You can see how this might cause some odd airflow coming out of the carb. Took a rotary tool with sanding drum and just angled the high edge to the low edge to smooth things a little. In reality this probably isn't even close to gentle enough to make this better, but it is a start. I'll probably cut a new spacer out of aluminum some time in the future and maybe lengthen the space so I can smooth this more gently.


carb spacer 2


And that's about it. Putting everything back together and slap on the K&N filter that also comes in the race kit. After letting the float bowl fill back up and a few kicks to get gas into all the passages, it fired right up and ran nice. I had to turn the idle speed adjustment out (down) a lot. It was also recommended to put some silicone or some other compound on the idle speed screw to keep it from changing due to vibration. It's pretty loose so I would say this is good advice, I'll probably hit it with some Loctite green compound which should be strong enough to prevent it backing out, but allow it to be turned when needed.


carb finished


Not a hard job at all, and totally worth the time it took.