2011 KTM 450 EXC FACTORY FUELING

Hi,

I'm having trouble with how my bike runs, it starts ok on choke and when i switch it off after a couple of mins it wont idle smoothly and wants to cut out, if i rev it, it increases and then idles to fast for a bit sometimes it settles out to a non smooth idle. Whilst giving it blips on the throtle it seems to pop from the exhaust a bit more than it did too. When out riding mid range to full throttle seem fine .

I've had the carb (fcr 39) to bits and there was a small amount of dirt in the bottom so i cleaned it all out plus i had the jets out and blasted them out too but still the same issues? Its ridden at sea level to maybe 1500ft and has a 40 pilot and a 180 main. pilot is 1.5 turns out.

Any help would be great.

Has your bike been desmogged?
Are you still running all the factory emissions equipment?
If you are, you may have something clogged up or in need of replacement as far as emissions devices go.
What's your plug look Like? Sounds like it's too lean. Is plug white?
Brown or tan is better than white.
Try a 172 or 175 main.
Fuel screw, give it a 1/4 turn more fuel.
JD jet kit is recommended.


Sent from my SM-G955U using ThumperTalk mobile app

Sounds like a dirty pilot jet.

Hi all,

It was running fine last week.

Its all standard apart from having the little insert that screws into the tailpipe with the star shaped nut removed.

Whats the electric plug for on the top of the carb?

Regards Ash.

It sounds too lean. If opening the exhaust caused the problem,  then try turning the fuel screw out a little.  If that helps but you have to turn it out a lot, then try a larger pilot jet.  

Sorry, I missed the part about blasting out the Jets. My XR 400 was giving me similar problems. It would only idle with the choke on half or full on. I screwed the pilot screw in to richen it and now it's fine. 

I it ran good before dirt in carb then keep cleaning the carb, blow out all the passages again and again.

 Don't screw with jetting if it ran good before, Did you count the turns on the fuel screw when you took it out to clean?

Edited by gitenby
On 8/11/2017 at 4:23 PM, DASHER1275 said:

Whats the electric plug for on the top of the carb?

Regards Ash.

 it's either a power jet or TPS, I'm new to KTM's so not sure what carbs they had

1 hour ago, gitenby said:

I it ran good before dirt in carb then keep cleaning the carb, blow out all the passages again and again.

 Don't screw with jetting if it ran good before, Did you count the turns on the fuel screw when you took it out to clean?

Normally you would be correct, but he said in a later post that the problem began after he removed something from the exhaust.  He can verify that this was the cause of the problem by putting it back in the exhaust and see if the problem goes away. :)  If the cause is indeed caused by opening the exhaust, then he's going to need more fuel for sure (or plug the exhaust back up). 

Edited by sirthumpalot
10 hours ago, sirthumpalot said:

Normally you would be correct, but he said in a later post that the problem began after he removed something from the exhaust.  He can verify that this was the cause of the problem by putting it back in the exhaust and see if the problem goes away. :)  If the cause is indeed caused by opening the exhaust, then he's going to need more fuel for sure (or plug the exhaust back up). 

Very notable point but note that OP said: "When out riding mid range to full throttle seem fine" 

Throttle position is a key that usually points to one of the three carb circuits and the fuel screw handles 0 - 1/4 throttle. 

When factoring in dirt in bowl, effected by throttle position, lean indications, poor idle usually points toward dirty or ethanol gummed up carb and OP may not have removed the fuel screw to thoroughly clean that circuit.

So, if it was me, I'd pull the fuel screw while counting the turns, clean the entire carb again but concentrating on the pilot circuit and fuel screw passages.

Edited by gitenby

Hi,

Cleaned carb out another x2, half turn open on the fuel screw and all fine again thanks :goofy:

I've changed plug been out for a ride for 2hrs checked it and its quite light in color so i'm going to change from a  #40 pilot to a #42 and ive ordered a easy mixture adjustment screw does this sound ok?

Regards

Ash. from the uk.

2 hours ago, DASHER1275 said:

I've changed plug been out for a ride for 2hrs checked it and its quite light in color so i'm going to change from a  #40 pilot to a #42 and ive ordered a easy mixture adjustment screw does this sound ok?

Regards

Ash. from the uk.

Look deep inside the insulator for the color.

So you can't get rich enough (CCW) with the fuel screw adjustment so you're increasing the pilot? You must properly set the fuel screw at idle to see if your pilot is correct, did you do that?

 

 

 

Hi,

Yes did that and it would only run ok at 4 1/2 turns out on the fuel screw with a new #40 pilot fitted and Ive put on a ackropovic can now as well.

Ive now upped the pilot to a 42, 1 3/4 turns out on the fuel screw and it runs much better, hardly any decel pops, picks up much better and idles like a sewing machine.

:goofy:

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