Been getting mixed information on the jetting of my KFX 400 and havent been able to nail it yet. So had the oppurtunity to speak to a mechanic for a race team out of SLC. They do not race the Z400...actually i think they race the Honda 250r...However they have done high performance mods on alot of Z400's and they highly recommend that i get the Moose Jet Kit (?? never heard of it) and make sure i follow the directions on the needle adjustment for my altitude as that is the only way I will truly hit the mid-range on the head. Anyone heard of a Moose Jet Kit and what do they run...how hard are they to install...thanks for the feedback and hope this helps.

 

You can get all the jets you will ever need for 1/2 the price of any jet kit. A jet kit is just jets and a needle.

Just stop listening to the people that tell you to put a huge main in your Z and leave the rest stock. That's half the problem.

What jetting do you have now (everything, main, needle, pilot, pilot screw) and what is "modified" on your stock airbox.

 

...how hard are they to install...

Hey Bosox07, I just rejetted my z with dynojet. The KFX has the same carb, I found it a little difficult to get the screws out on the bowl (not a whole lot of room to play with). What I ended up doing is taking the carb out completely and installing the jet kit. The other thing I did was I called Layton Cycle and talked to Steve in the service department, he gave me advice on what Dynojet to use so I didn't have to keep taking the carb out. Hope that helps.

 

There is a 145 in there now...it back fires and running lean

I have removed the air box cover, the snorkel and have installed a pro flo kit (mainfold and k/n filter with outerwear)

 

I don't know what elev. you're at but I'm at about 1000' and run a 155 main(DJ) with similar mods and I may be a little on the lean side.

 

Whoops...left that out didnt I...I am at 5000 ft

 

155 main, Needle at #4 (from the top), 25 pilot, 3 turns out.

Should make it rip. The Moose jet kit I'm sure comes with a needle that is the same as Alba or DJ, so if you must buy a kit, do so. But, if I were you I'd simply get main jets from 145 to 170, 25 and 27.5 pilots and a new adjustable needle. Then you have your own jet kit and saved a bunch of money. Jets are normally 2.50 a piece and the needle is around $15.