[ktm450xc]

Need help re-jetting.
Opened side of air box with 5 one inch holes and mixed fuel 91 octane and 111 octane fifty/fifty.
Seems to sputter at full throttle in all gears.
Ran good until opening air box and running 111 octane.

Using dial a jet at 150 main, CT Racing Exhaust, Cam and worked good until opening air box and changed fuel.

Changed main Jet to 155 and no change.

 

[VoodooMagic]

I'd start at 170 main 45 pilot, jets are cheap so get 160,165,170,175,180 and see what works best. Elevations going come into play also. If your going to ride higher than where you are tuning then find a jet that runs good at 3 turns out on fuel mix screw, that way when you get to location you can turn in the fuel screw and not have to do a jet change when you get there. Opposite for going lower, jet so your about 1/2 turn out and running good then you can adjust to 3 turns out. Its recommended not to accede more than 3 turns out because your fuel mix screw might fall out beyond that. You should be ok with adjustments if your not going to change more than about 1000ft elevation. If your making more of a change in elevation than say 1500ft I'd bring your jets with ya for the best results. One more thing on your fuel, you probably already know this but when use a certain octane you don't want to go back down. Your probably fine now for your short run but when your quad gets used to the higher octane it will ping if you go back lower again.
-Voodoo

 

[ktm450xc]

First time running (DIAL A JET).

Was running a 150 main before opening box and changeD fuel. Ran grat with a 150 main with Dial A Jet.

Thanks for the reply.

 

[VoodooMagic]

Sorry I never used that jetting before. I looked at there website and that thing seems pretty odd. Anyway I see it has 5 adjustments, did you just change the main or did you try the 5 adjustments it has? I'd still get a 160,165 main anyway and see if that gets you closer. Hopefully there is another member here that has used the dial-a-jet and can help you out more or maybe you can call the company it came from and see what they suggest. Please reply after you get it sorted out.

 

[ktm450xc]

THANKS FOR YOUR REPLY.
WAS RUNNING JD JETTING SYSTEM UNTIL WE PURCHASED PIPE AND CAM.
GUY RECOMMANDED DIAL A JET FOR THIS SET UP. WILL HAVE TO JUST PLAY WITH SOME MORE.

YES I TRIED ALL POSITIONS ON THE DIAL WITH THE 150 MAIN. MY BOY SAID IT STAYED THE SAME IN ALL GEARS AT FULL THROTTLE.

 

[Bronson90]

i would loose the 111 octane for sure unless you are running a high compression piston that requires it. i guarantee on a dyno the 91/111 mix would make less hp than running straght 91...

in a nutshell, you ALWAYS want to use the absolute lowest possible octane available that wont detontate. the lower the octane the faster it burns and the higher the octane the slower it burns. with higher compressions you risk low octane fuels detonating under compression before the piston reaches tdc and the spark ignites it. so hence the reason why higher octane fuels burn slower, so they dont detontate under the higher compression before the spark can ignite it.

i hope this helps, good luck!

 

[ktm450xc]

Thanks.
Any recommendation for the main jet after opening up the side air box?

Have you ever used the Dial A Jet?

 

[Bronson90]

Thanks.
Any recommendation for the main jet after opening up the side air box?

Have you ever used the Dial A Jet?

is your problem in just one area of the throttle (idle to 1/4, 1/4 - 3/4, 3/4 - wot) or is it the entire throttle range idle - wot?

i have no experience with the dial-a-jet kit, but i have heard that Thunder Products has great jetting technical service available over the phone...

150 main sounds way to lean to me, but i know dial-a-jet is completely different from standard jetting... if it were standard jetting with your mods i would start at a 180 main, 45 pilot, needle 4th position, 2-3/4 fuel.

 

[ktm450xc]

Thanks Bronson,

Just went back to 91 Octane and up the main Jet to a 165. Had to adjust the dial to full fat and seem to run great. Could use a 170 main but will get alot hotter here in Oklahoma this summer. Will let my son try it tonight to see if it run's better then last night.

Word of advise: becareful when opening your air box up. Put five 1inch holes on left side. Seem to run fine at 150 main before open box.

Before switching to dial a jet, was running JD Jetting with a 170 main. Ran great but switched to Dial A Jet after exhaust and cam mod.

By the way Bronson, my son loved the hat and DVD he won last month...

Again thanks for the help.

 

[VoodooMagic]

No love for the voodoo, If you read my 1st reply I would have had you right on track

Anyway Glad you got it all fixed.
-Voodoo

 

[ktm450xc]

THANKS FOR YOUR REPLY.
WAS RUNNING JD JETTING SYSTEM UNTIL WE PURCHASED PIPE AND CAM.
GUY RECOMMANDED DIAL A JET FOR THIS SET UP. WILL HAVE TO JUST PLAY WITH SOME MORE.

YES I TRIED ALL POSITIONS ON THE DIAL WITH THE 150 MAIN. MY BOY SAID IT STAYED THE SAME IN ALL GEARS AT FULL THROTTLE.

Voodooo,

I did respond to your reply.

Sorry I just picked Bronson because I kinda delt with him before.

Looks like might have to go up to a 170 main.
Boy said it was better but still not perfect.

Again thanks for everybodies help.

Birddog Racing #30

 

[Bronson90]

i typically don't rejet anytime through out the year... i have friends who have mains/pilots and needles it seems for every different type of riding, constantly changing everything. that is not for me...

I prefer to work out all my jetting issues on the dyno and be done with it... my way has proven to be very good to me and i have no plans on changing it!

 

[cmcn6]

I have ct full systum and open air box with k&n I run 180 main jet at 3000ft at sea level 185

 

[ktm450xc]

I have ct full systum and open air box with k&n I run 180 main jet at 3000ft at sea level 185

Are you using Dial A Jet???

 

[cmcn6]

no just jets

 

[Bronson90]

please take some detailed pics of your head pipe, mid-pipe and silencer...

i am looking into the ct racing full exhaust and want to see pics of how the head pipe comes together so i can have a good idea of how it scavenges...

thanks.

you can post them here or email them to me.