Forgive me but I'm mechanically challenged.

I'm ready to rejet my KFX400. Do you have to remove the carb from the engine or can it be done without removing it? I've searched through old posts and it sounds like getting some of the screws out can be a big problem. Any other important items that I should know.

Thanks in advance!

 

You don't have to pull the carb completly off, I would just have a place that has a dyno do it for you. Jetting is some thing I don't have patients for.

 

Your initial rejet will call for removal from the engine compartment. You don't have to disconnect it completely, just get it out far enough to get a firm grip with your knees on it. You'll need both hands for the impact screw driver to remove the stock brass bolts on the bowl. Once you replace those with the allen head bolts complete removal is not necessary, it just has to be twisted a little to get at everything. I can rejet and change needle positions on mine in about 20min. now. Your not tearing the whole carb apart, so it's not real difficult. Keeping track of where you laid the bowl screws is the hardest part to it. Just pay attention to how everything came off and you'll be fine. If you need any help, you can PM me so none of the yahoos that post on here from time to time can give you bad advice. I've rejetted my Z twice now for different mods, and don't have any studders or hesitations anywhere, so I'd say I'm pretty decent at it. Also rejetted a yfz w/o many probs.

 

craZ400,

Thanks for the info. I see you have a CT pipe. That's what I bought. The jet kit only had two main jets! I was quite surprised by that. Seems like that would make it kind of tough to dial it in (or make it nice & easy for those of us who don't know what they're doing). It also came with no instructions on the 7 disc spark arrester system. Am I supposed to know what I'm doing or what? I know that you can remove some of the discs but how do you know what to do with no instructions or a description of the theory of operation. I'm going on the assumption that I install it "as shipped" unless I do some other mods besides the pipe itself.

Can you shed some light on the subject for me?

 

Sure can. Your right about using as shipped, you need all 7 discs for stock application. Like you figured, if you mod the engine further, then you'll need to buy extra discs.

As for jetting: To start, make sure your gas tank is in ON. Remove the fuel line with a cup or something under it so you don't get fuel everywhere. Then pull the drain hose that is connected to the bottom of the carb out to where you can stick the end of it in the cup. Next, open the drain valve on the bottom of the carb, it has a screw head on it, to let all the gas out of the bowl, once again, so your not covered in gas. Loosen the clmps on either side of the carb till they spin freely. Now twist, turn, and pull, don't forget to cuss Suzuki once in a while, and jerk the carb out to the side of the bike. I found the side opposite the pipe is the easiest.LOL Remove the four brass screws any way you can without breaking them. Slide the bowl off and remove the main jet, it's surrounded by a brass shield thing. Put in the 162.5 and put on bowl. Next is the needle. Remove the black cap, and spring, on the top of the carb. Pull the slide out of the carb. Take a small pair of needle nose and reach down and pull out the whitish rectangular piece of plastic. Now use the needle nose to pull out the needle jet. Slide all the old washers off and put them on your new needle. The C-clip that came with your new needle should be on the 3rd clip down from the top as it would be in the carb. Remember to put the plastic washer and metal washer from your stock needle on your new one. You should have got instructions on that. If you forget to put those washers on, you'll get a dead spot from 1/4 to 1/2 throttle, guess how I know? Put the new needle jet back in very carefully so you don't lose any washers. When you go to put the plug back on over the needle, make sure you have the four prongs lined up with the four spaces on the plug. Now just put the slide back in making sure the needle goes in it's hole in the bottom of the carb. put the spring and cap back on, and take a breath, the hard part is done. Last is the air screw. It is located directly in front of the float bowl. Run it all the way in (righty tighty), gently, till you feel it stop. Then back it out 2.5 to 3 full turns. I usually count in halves, since my wrist will only spin 180 deg., to keep track. After all that, you get to put her back together, pushing and twisting and cussing Suzuki some more. Make sure the carb is properly aligned to the intake, and tighten your clamps till you can't twist your carb in the boots. Hook the fuel hose back up, make sure the bowl drain valve is closed, put your tank on PRI, to get fuel back into your carb, and then fire her up, let her run for about 5-10 min. at idle to warm up, then blip the throttle as fast as you can to make sure it revs without a hesitation. Once that is established, slowly increase the rpms to make sure there aren't any dead spots. Last, let it slowly come back down off the rpms, once again, listening for dead spots. Your rev should sound smooth, no pops, or crackles, just snap.

I hope this is detailed enough, if it isn't, just ask about what your not clear on and I'll go into more detail. Good luck.

 

craZ you are the man![img]i/expressions/face-icon-small-happy.gif[/img]

Hopefully I'll be able to give you a successful report on Saturday.

 

No prob, any time. I look forward to your progress. Happy trails to you and yours.

 

craZ,

The worst part was getting the stock header pipe off. When you bolted on the CT pipe did you reuse the rubber spacers? It seemed like the thing to do but didn't seem 100% right. The bolt was too short to use the washer. How did you do it?