The Dynojet website isn't very specific with regards to the qualifying factors that determine which stage is right for your bike. Both kits can be used with a good aftermarket exhaust and K&N filter. But drilling the airbox is supposed to be the distinguishing factor that seperates the two?

In my opinion, the stage 2 kit seems like one hell of big jump from the stage 1 kit even for a drilled airbox!! My bike currently has a full exhaust, K&N, and a 6 degree ignition advancer.

Right now my current carb settings include the dyojet needles set at the stage 1 position and stock 110 kehin jets which is the same as a dynojet 106 (2 sizes higher then the stage 1 102s.) OVerall the bike runs great but Im still in doubt as to whether or not these are the right settings? On the Factory Pro site, they recommend kehin 120 jets? I also know for a fact that dropping my needle settings from the stage 2 to the stage 1 setting helped me loose about 1 second in a quarter mile. I also know for a fact when I ran the DJ98s (stock exhaust jets) it sputtered at higher rpms meaning I was runing lean. SO my biggest question is should I drop down to the recommended DJ102s, or go higher in jet sizes to like a Kehin 120?

What is everyone else here running and what are your mods?

Here is a conversion chart between Dynojet and Kehin.

Width------Kehein # -- DynoJets # -- Mikuni #
0,0350---- 92,5--------- 92----------- 86,3
0,0360---- 95----------- 94----------- 88,1
0,0370---- 97,5--------- 96----------- 90,0
0,0380---- 100---------- 98----------- 91,9
0,0390---- 102,5------- 100---------- 93,8
0,0400---- 105--------- 102---------- 95,6
0,0410---- 107,5------- 104---------- 97,5
0,0420---- 110--------- 106---------- 99,4
0,0430---- 112,5------- 108--------- 101,3
0,0440---- 115--------- 110--------- 103,1
0,0450---- 117,5------- 112--------- 105,0
0,0460---- 120--------- 114--------- 106,9
0,0470---- 122,5------- 116--------- 108,8
0,0480---- 125--------- 118--------- 110,6
0,0490---- 127,5------- 120--------- 112,5
0,0500---- 130--------- 122--------- 114,4


Also here are the Dynojet instructions for a 1990. http://www.dynojet.com/pdf/1135.pdf
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1990 Honda CBR600F
K&N filter (removed air tubes under lid)
Yoshimura header with Vance & Hines SS2-R muffler
Factory Pro 6 degree Ignition Advancer
jetted