Now you can see the funny little fuel screw. Take it out. Make sure the spring washer and O-ring come out with it. You need that O-ring. One of the most common calls we get is, "why won't my bike idle?" Many times it's because that O-ring is either torn or missing.





Put the new F2 Racing fuel screw in. Spring first, washer second, O-ring last. The F2 fuel screw is brass, since alu¬minum units'tend to seize with corro¬sion. Turn it in until it seats. Not tight¬ened, just until it seats. You don't want to damage the carb body.





Take the 17mm float bowl plug out and change the main jets for whatever elevation you will be riding at. The table in the F2 kit makes it pretty easy to figure aut





On this bike, we opted for the F2 Racing Fast Cap. It makes for enhanced throttle response on the KLX. The redesigned shape keeps the fuel concentrated in the center of the float bowl for more even fueling. Just swap the factory O-ring.


The biggest thing that trashes valves is dirt getting in the engine. There is a filter on everything, the air filter, oil filter, etc. Except for one place...the carb vent lines. The first place the dirt goes is right into the carb and straight into the intake. Unfortunately, the next step is valve wear. Fortunately, the F2 Trash Can was developed to catch the junk before it makes it to the carb.




The needle gets changed to an adjustable one that promotes more mid range and top end power. F2 gets a lot of questions about this too. Why are your main jets different than what everyone else uses? It's because the needle taper is different. Their kits have much more midrange power than stock and still have great throttle response. Plus about 15 percent better mileage, and it is now adjustable for elevation changes.
Here is where the tweezers that come with the Powerback kit come in handy, since we don't know anybody who has fingers small enough to complete the task of removing the needle. Refer back to the F2 jetting chart and set the needle position. Always count from the top or flat end of the needle. On the KLX they set it at two clip positions from the top. With the carb assembled, it is time to put it back in the manifold. Make sure the TPS sensor gets plugged back in


When you put the hot start back in, make sure it is tight. F2 gets calls say¬ing that the bike still bogs, or that it is hard starting, and this where you need to check. Make sure that when the tank goes back on that you don't pinch the hot start cable and it has enough slack in it. If the plunger gets pulled even a little, you will go bald trying to jet out a lean condition that is caused by this. Remember to reinstall the throttle cables.



At this point just put the shock back in the bike. Swing the sub-frame back down and bolt it back together. Make sure, though, that the air box boot is properly on the carb. Hook up the hose to the air-box that you took off earlier. Put your pipe back on. One of the advantages to the F2racing Powerback kit is that the stock pipe works very well with the kit and keeps it way quiet.
As you put the tank back on, make sure the throttle cables and hot start don't get pinched. You don't want a sticky throttle. Before you put the seat back on, remove the black foam on the bottom of the seat. You may have to resort to a scraper and some carb cleaner. It can be a bit of a sticky mess, but it is worth it to get more flow to the airbox.


A BREATH OF FRESH AIR
In talking with F2 we've learned that their phone lines are jammed with technical questions about today's off-road strokes. With all of the on-line chat rooms and websites that attempt to educate the enthusi¬ast, the amount of bad information readily available is. monumental. Their set-by-step instructions with photos are easy to follow. They try to distill the process down to a palatable level and pride themselves on improving the status quo. And besides the performance improve¬ments, just removing the fear factor of working on your machine is worth the price of the ticket

www. f2racing. net
(928) 814-67100