I recently replaced the stock a/f mixture screw with an EZ-turn screw, and after a summer of being caught in the rain, it seized in the threaded bore. Knowing that without a spare carb sitting on the workbench, trying to remove the soft, brass EZ-turn screw would result in it breaking, ruining the carb all together. I scored a new carb, (Thanks Dean-O) and this whole gig is to show me swapping over my “custom” parts, and so others can see the locations of pilot jets, main jets and diaphragm/jet needles.
First you need to remove the carb. Remove the air cleaner, and backing plate. The backing plate on the Evo is basically the mount that stabilizes the front of the carb. Unhook the fuel line and both throttle cables. Although not necessary, I mark one of the cables to make sure I don’t get them mixed up. It’s hard to mix them up, just due to their length difference, but anything’s possible. To loosen the throttle cables, just uncover and unadjust the cable adjusters near the throttle, under the little, black rubber boots. Shorten the adjuster, putting slack in the cables.
You’ll also need to unhook the VOES vacuum line and the float bowel overflow line. Just let them hang.
On the left side, (shift lever side) you need to unhook your choke cable. It’s a 5/8” nut on the back of the mounting bracket/motor mount. It’s easier to unhook the choke there, then off the carb, IMHO. Once your cables, fuel line and cables are disconnected, the carb pulls out of a rubber grommet/seal that’s in the end of the intake.
Once off, I drain mine by removing the bowel over a container. With the carb upside down, and the bowel off, you’ll see the float, and two ports for jets. The larger port (top) is for the main jet, and the smaller one (at about 9 oclock) is for the pilot jet.
This carb is stock. It’s so virgin, the a/f mixture screw was still capped. Too boot, the factory a/f setting on the screw was barely 1/8th of a turn out. Yep…..from the factory.
Stock jetting for this was 170 main and a 42 pilot. I have V&H straight-shots and an A/N air filter. I run a 180 main and a 45 pilot. The jets a re brass and soft, so no need to tighten them like a lug nut on a dump truck. You'll not how long the main jet "looks" in this pic, because it's still attached to the emulsion tube. Separate them to replace the jet.
Take care not to hit or press on the float, as you’ll have to reset the float level again, and that’s another story for another day. Not difficult, just another few steps. Put your float bowel back on, before taking anything else apart. Sometimes it helps to have a small selection of jets, to be able to change them at will, for best running results. Numerous jets come with a Dynojet kit. Others can be bought at your dealer for a few bucks.
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