Athena big bore set up

[ifixtheyride]

I just had to change my valves and while it was down I installed the Athena big bore on my 03KFX400 now its not running right. It wants to fall completely on its face when given quick throttle it idles fine, cruises ok but punching it or putting load on it doesn't. My old set up was:
K&N air filter with K&N lid.
White bros slip on
K&N jet kit set at 3rd position on needle and a 150 main jet. It ran great there until it started to start hard so I found a bad valve and had it fixed.

I tried adjusting the jets as my plug looks hot very white. I went from 150 to 165 in 005 steps and seemed to help open throttle. Raised needle to 4 then 5 and no help.
Lowered needle back to 3 then 2 no help. The plug still seems white on the ceramic but on the outer threads it is black soot.

If anyone is running this set up what are your jet and needle settings. I'm in Pennsyvania and altitude is around 1000 to 1800 feet.
My valves are Kibble White and gaps are .011 Exhaust and .007 Intake

[cataway]

so why did you stop at a 165 ? if it wants more gas give it to it.
and what kind of jets you using?

[ifixtheyride]

I have a dyno Jet kit and the biggest jet was the 165 in the kit. I did some more tinkering after I posted the thread. I'm not so sure it carb. Idles great and in nuetral excepts gas hit first seems ok but second itjust falls that's not main jet if low in throttle. Hit third and it picks back up full throttle ok hit fourth falls flat down shift and get RPM up and ok it has no take off punch. Moved needle from 1 to 5 no change. I have removed the carb about 15 times now its clean as a whissle and the float is good. Is there some stupid rev limiter that I don't know about? I do have a Procom CDI but it has been working before the bore kit was installed although I think it stinks did'nt see much diff then stock and reverse still cuts out. I put new AVS levers on and removed the clutch switch just soldered them together that shouldn't hurt spark should it?

[cataway]

as i suspected ,you using DJ jets, there OK but there not the same as mikuni jets . and DJ jets seam to be harder to get from a dealer, any way try a mikuni 165 thats just about as big as you'll need and a lot easer to come by.
to give some idea of what i mean here is a short list comparing
different kinds of jets.
Width------Keihin # -- DynoJet # -- Mikuni #

0.0690---- 177.5------- 160--------- 150.0
0.0700---- 180--------- 162--------- 151.9
0.0710---- 182.5------- 164--------- 153.8
0.0720---- 185--------- 166--------- 155.6
0.0730---- 187.5------- 168--------- 157.5
0.0740---- 190--------- 170--------- 159.4
0.0750---- 192.5------- 172--------- 161.3
0.0760---- 195--------- 174--------- 163.1
0.0770---- 197.5------- 176--------- 165.0
0.0780---- 200--------- 178--------- 166.9
0.0790---- 202.5------- 180--------- 168.8

[ifixtheyride]

Ok, Thanks I did not know they varied so much I assummed that the number indicated inside diameter of jet and that 160mm is 160mm no matter who's jet was used. My problem is just adding the big bore I didn't expect it to change jetting that drastic. I'm not talking about tmy quad not running at its best I would consider my condition right now as running very poorly not barely ridable an certainly not able to run on any track it would dive on jumps and I'd get killed. My problem seems to be more major now.

Thanks,
Bill

[cataway]

you may get to change the pilot jet to a #25 or even a #27

[ifixtheyride]

Ok, bone head me! Whenever the manuals tell you to check the gas filters don't be lazy do it. I removed the filters from the tank and wow the reserve filter was almost clogged. It's amazing what can get in the tank especially when kids ride. I got excited when I found this totally cleaned it and filled the tank took it for a ride still had dam problem in second gear and slight 4th. I read a few threads down this morning and someone had one on sticking rev limiter. Removing CDI is not possible but the stupid nuetral switch is much more then nuetral and it was oxidized. I removed it brushed contacts and now it rips like a raped ape. Now when it gets warmer I can hone in on the carb tuning. Problems are not always carbs remember that and why it broke when I did the bore I don't know maybe because it wasn't ridden for a week or more and it oxidized what a bad design.

Thanks cataway for the info I will use it when I tune up the carb. Where did you get that info anyway on jetting?:) :)

[cataway]

http://www.z400central.com/invision/index.php?showtopic=72965&st=0&gopid=614995&#entry614995