2007 KTM 450sxf bog!

I just recently bought a 2007 450 sx-f. The bike idles well on choke or off choke but if you have the choke off and give the throttle a twist and let go the bike bogs and stalls. It also happens when I accelerate hard and brake into a corner. The only time it doesn't do this is when the choke is on. It's a must fix and need help!


I put some new fuel in 98 ocatane and just removed the carby screw and noticed some improvement. It did still stall with the clutch full in when I was turning. (no acceleration)

How to eliminate the 'Bog'

You should set the fuel screw for a perfect idle and then leave it alone. Do not try to make the carb idle circuit do something it is not intended for.

How to eliminate the 'Bog'

You should set the fuel screw for a perfect idle and then leave it alone. Do not try to make the carb idle circuit do something it is not intended for.

Do i also need a carb bowl with an adjustable leak jet?

No, do not waste the money, unless you spend a lot of time riding in differt terrains, like flat out desert running and the next day, tight single track.

I just play around with mixture and put it to the recommended 1.5 out and the air mixture was way too high. In my manual it says adjust idle screw to 1400-1500 rpm and I am not sure how to do this. Can I please have help!

Fuel Screw/Pilot Jet

Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.

Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.

*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***

Turn the screw in until the idle becomes rough or the bike stalls.

if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.

If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.

Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.

If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.

If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.

If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,800 rpm, but go by the spec in your manual.

If you cannot tell or havethe tools to measure it, set rpm to a speed that the bike runs smooth, it may seem slightly high but slightly high is better for the bike than too low.

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