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couple questions about JD kit

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i just installed the JD kit in my 06 450X i followed the instructions exactly.

1. im just curious about somthing. is the jetting that jd offers for 6-9000 feet leaner or richer than stock? the red needle looks to be larger than the stocker which would lead me to think leaner. im just wondering because the bike ran pretty good stock. i have the tip removed from the stock exhaust and none of the instructions mentioned anything i should do different for that mod. i didnt cut the sides of the airbox out but did open the top of it under the seat a good amount.

2. about the AP pump mod with the O ring. correct me if i am wrong but as i read and understood somewhere the need for an AP in the first place is because when the throttle is snapped open you get a lean condition because air flows much faster than the fuel the AP compensates for this by adding a little extra fuel.

ive been reading a bit about carb mods and it seems everyone talks about getting the AP to delever a bigger shot of fuel.

as far as i can tell too much fuel is just as bad as too little. all your doing is causing the engine to run richer than necessary which doesnt make power.

i understand to some extent the carbs are adjusted a little on the lean side to pass emmissions but from what i see and the mechanism of the AP pump it seems the design is the way it is so you dont over do the amount of shot from the AP

with all that how is adding more fuel helping anything?

i have not noticed any real performance gains from installing the kit.

i adjusted the idle mix per the instructions. i found i need to be close to 2 turns out to keep a smooth idle and i noticed minimal popping on decel which tells me its pretty close. i notice at just off idle and rolling in 1st gear there is some slight hesitation before the power kicks in.

at idle in neutral a snap of the throttle from the factory spec 1700 rpm idle i can kill the engine almost every time i snap the throttle open. if i twist slow then fast it revs up perfectly.

this tells me there is either too much fuel from the AP or its too lean off idle. its difficult to tell at this point which way.

one final comment though i did notice with the stock setup there was faint black puffs of smoke from the exhaust when revving the engine. this tells me it was slightly rich and the AP probly richened it just enough to produce some smoke when snapping the throttle open. it does not do this now that i could see with the JD setup. again this tells me its a little leaner. i am always worried about getting too lean because i dont want to run it too hot or damage anything.

while riding with the stock setup yesterday in the woods it was about 90 degrees. i found the temperature never got above 191 degrees according to the water temp gauge installed for my trail tech vapor computer. im certain this was no where near too hot considering the ambient air temp. is that low or high considering the fact i was ttrail riding on 90 degree day?

if anyone can provide some insite and answers that would be greatly appreciated.

thanks

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-Removing the exhaust tip will have not have a major impact on your kit settings. Adjusting the fuel screw was a good move to keep the idle running steady with this change.

-The accelerator pump is not pushing more fuel with the O-ring added to the linkage from your kit. This is only forcing it out faster, to improve the atomizing and response when you snap the throttle. When the airbox is opened up, there is more airflow, resulting in a need to improve the the fuel delivery when the throttle is lifted quickly.

The 6000-9000ft setting in the kit is richer in some portions and leaner in other portions of the throttle range. The lack of black smoke is probably because it is leaner overall than before.

Thanks,

James

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-Removing the exhaust tip will have not have a major impact on your kit settings. Adjusting the fuel screw was a good move to keep the idle running steady with this change.

-The accelerator pump is not pushing more fuel with the O-ring added to the linkage from your kit. This is only forcing it out faster, to improve the atomizing and response when you snap the throttle. When the airbox is opened up, there is more airflow, resulting in a need to improve the the fuel delivery when the throttle is lifted quickly.

The 6000-9000ft setting in the kit is richer in some portions and leaner in other portions of the throttle range. The lack of black smoke is probably because it is leaner overall than before.

Thanks,

James

thanks james, you didnt answer one question though. whats the story with the just off idle hesitation? is there anything i can do to correct this? i know it only happens when in neutral but a couple times it will bog while rolling. sometimes ill idle up to a water puddle or other obsticle in 1st gear and intend to rap the throttle to wheelie over the obsticle. i need to make sure the bike will respond reliably in this situation.

thanks

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Try turning the fuel screw inwards, your idle is probably richer than needed and not running as crisp as it should. Many times, when setting the idle mixture while sitting still, the setting ends up richer than when riding in real world, rougher terrain. The float level tends to rise and the on/off/on throttle situations have the accelerator pump richening jetting too. Keeping the idle slightly leaner should help the motor stay running cleaner at low speeds.

Secondly, considering you've both removed the baffle and modified the airbox, try a test ride with the next bigger main jet from the kit. The bigger main jet was mentioned in the instructions below "Racing Modifications", although it was referring to sea level, the same applies at higher elevations.

I've also ridden the CRF450X at higher elevations, so have some first hand experience with your bike.

Colorado Picture

Thanks,

James

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