2006 ktm 525exc-g jetting problems

have 2006 ktm 525exc-g when whacking thottle from 0 to 1/4 bike will hesitate or die top end pulls good stock needle at 3rd from top. pilot 45 main 178. also pops quite a bit on decel. fuel mixtyre screw dosent seem to make a diffrence at what position. ran from 1 1/4 turns to 2 turns out.

I am in no way shape or form claiming to be an expert on this, but my guess is you need to verify accel pump timing and the leak jet size.

Based on a friends 525EXC, I suspect you have a FCR39MX carb, that may not have a leak jet float bowl. (R&D does have modified float bowl, plus their own w/adjustable leak jet)

From my limited time around the EXC, your posted jetting appears close, still think it would benefit from having a leak jet to help fine tune that bottom end bog/stall out....some light decel popcorn like popping is normal.....try turning the fuel screw out a bit more and see what affect it has.

Try a search for AP timing and/or Leak Jet (& leak jet bowl) and see what you find for your bike......JD jetting kit will be mentioned a bunch too. I didn't use one, but know others that have w/great success

Just for reference only, my Husky TE510 has a FCR41MX and had a pop/stall issue or bogged off the bottom if it didn't die.

Still not 100% fixed however it's much much better.

My current jetting, riding mostly 3000ft to 6500ft, is: (FYI: the TE510 does seem to take little richer jetting than the 525EXC)

Main: 180

Needle: OBDVR at 3rd clip down

Pilot: 48

Kouba Brass Extended Fuel Screw: varies w/elevation, but typ about 2 turns out

Leak Jet: 45

AP Timing: Just missing slide, w/arm adjusted out 2.75mm from base, and #78 O-Ring over AP arm

(you'll find alot more info on this in the search)

First thing you need to seperate AC pump from jetting!

Pump is responce!

Jetting is steady throttle!

Your combo has a needle with a very low taper angle, result is its quite lean in the upper throttle ranges and the needle blocks the flow of the main jet, thus the main jet size is ineffective. There is a bunch of power to be gained buy putting in a needle that has a proper taper. Kehein makes another series of needles with a lot more taper, they can work good but they have so much taper that the main jet needs to be in a different range, example an OCEMN needle and main jet in the 155 to 162 range works well.

A better combo is a needle with some more taper but not so much that is screws with the range of main jet, that is only available from JDjetting.com.

Back to the AC pump, there are a bunch of ways to modify the squirt, the no brainer is to buy the accelerator pump diaphram for a Honda. If you buy the JD kit he also makes a little piece that goes on the bottom of your diaphram to accomplish the same thing,

When I set them up I don't use either one, I modify the stock needles taper to suit the engine, also modify the stock AC pump parts to suit.

Dont know if you figured out your jetting, I wanted to pas on some info that might help. Try raising your needle one or two positions.

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