Hopefully the problem I'm having is not an isolated one. I just installed a K & N air filter and dynojet kit on my 04 Z400, in addition to the team suzuki yoshi slip on silencer W/ the TEC/ spark arrestor removed. I followed dynojet's instructions to the tee, and am using the 124 main jet, their supplied needle with the clip on the 3rd groove, and the fuel screw turned out 3.5 turns. The areas I ride are all 1000 ft. above sea level or less, and the temp around here is hovering in the mid 40's. Problem is whenever I ride, there is a huge dead spot just above idle around 1/8 or 1/4 throttle, and it tends to bog down. Did a plug chop after riding for a little bit, and the insulator was white as a sheet. I have tried adjusting the fuel screw to no avail, and it seems like I have two issues going on at once. Seems rich on the low end and lean on the high. I'm terrible with carbs, so anybodys input would be greatly appreciated-( Was gonna go to Attica this weekend, but dont want to tear my bike up) Thanks ahead of time[img]i/expressions/face-icon-small-confused.gif[/img]

 

124 is too small. Stock is 135. If you leave the lid on your airbox I might try a 145 to 150 main. I run a 160 with a MBRP slip-on, UNI filter, and the lid off. Runs great........

 

Do you have the airbox lid off?? Well even if you dont you need to jet up big time. If the air box is on start around a 145 main jet, as for if you have the airbox off you should be at 165 to a 170 main jet. let us know what happens.

 

The airbox lid is still on, as I ride in alot of either real dusty or real muddy conditions ( Indiana) . I had a feeling that the main jet was too small, but what about the bogging in the low rpm range? It almost dies when I put it In reverse. Think it has something to do with the needle they supplied?

 

I run a 170 jet you should be around 145-160

 

Yeah i ride alot in indiana at the Badlandz, Haspiin and i ride with the air box lid off with no problems. Take the lid of and rejet to a 165 and put the stock needle in while moving the clip down one.

 

Thanks for the suggestions- The stock needle only has one groove on it though, so u think I should keep the dynojet needle? If so, what would be a good starting point to try the clip on?

 

put the stock needle next to your after market needle and check were the stock clip is at compared to the notches on the aftermarket needle. That will give a good starting point.

 

The dynojet needle seems to be alot thinner taper- could this be my low rpm bogging problem? If I'm not mistaken wont a thinner taper make it richer? I'm have tempted to try the dial-a-jet but I'm a little leery about some of the things I've heard about it. For someone like me who knows little about carbs, it seems as it would simplify all of this (or make it 10 times worse)[img]i/expressions/face-icon-small-disgusted.gif[/img]

 

stock is a 130..