Stock KTM 525 XC Best Jetting Ktmbill Exhaust /FCI Combo
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  1. #1
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    Stock KTM 525 XC Best Jetting Ktmbill Exhaust /FCI Combo

    Hello Fellow Ktm Enthusiast,

    I am currently having a complete and full bottom to top service on my 2009 525 XC. I am also having them
    Install the All4Racing full exhaust from KtmBill and an FCI that I’d purchased. The stock carb also needed to be rebuilt due to the bike sitting with gas in it for over a year+ without starting or riding around with the previous owner.

    I do the majority of my riding at sea level and all the way up to 1700 feet.
    Does anyone have suggestions on what the optimal jetting would be for my current mods and riding elevations?
    KtmBill recommended 162 Main for his exhaust, but I also have an FCI going on so would that change things a bit?

    Thanks in advanced for any assistance.

    Cheers!

    Cheers!
    2009 KTM 525 XC
    -KTM Bill Full Exhaust
    -FCI

    -O-Ring Mod, R&D Float Bowl, Emulsion Tube, 41MM Carb
    -CT GNCC Race Package -
    CNC porting of the cylinder head, CNC Radius 5 angle valve job for +1mm over size valves, Set of new +1mm Valves, Performance Lightweight Valve Spring Kit with Titanium Retainers, Webcam 821 Grind Camshaft, Diamond Honed Cylinder and a JE 13:1 Hi Compression Piston
    Dyno: 60.7 HP and 40.3 TQ on VP 110

  2. #2
    Senior Member KTMATVHQ Member
    Join Date
    Nov 2015
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    354
    162 sounds right or close to it, Bill knows what he’s talking about. In my experience I did not need to change out MJ for the FCI. I want to say I remember moving the needle clip and re-adjusting fuel screw. You can pull spark plug and if it’s tan/slightly dark you are where you need to be, if it’s black you’re rich, and whitish you’re lean. Keep in mind MJ is pretty much wide open so if you are off on your main jet it won’t show until your pretty much wide open. If I doubt always run slightly rich over slightly lean.
    Pilot- approx. closed throttle to 1/8th 1/4th open
    Needle- pics up from about 1/4-3/4
    Main is from 3/4 to wide open

  3. #3
    Member Rookie
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    Oct 2015
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    46
    I would start with what ever Bill tells you to and fine tune from there, just know thats only a starting point. Don't forget the needle that you are running makes a big differance on the jets that will go with it. I have a 450 xc with a ktm bill pipe and all the rancho mods done with the hrc needle. I spent a lot of time finding out that what worked for several others did not work for me and I only came to that conclusion by a bike that was sluggish and I had to put a wideband to see just how far off I was. For me personally plug checks only got me in the ball park. I'm at sea level running the HRC needle on the 2nd clip, 40 pilot, 155 main and fuel screw out 1.5 (R&D Flexjet).

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  5. #4
    Member Rookie
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    Thanks for all the info.
    My bike just got out of the shop yesterday.

    They ended up just adjusting the clip and fuel screw I believe, but left everything else as far as jetting the same.
    There is no decel popping really at all, but the power, starting/low idle and overal response just doesn’t seem like it’s where it should be.
    There was some very old gas (small amount) in it for a while prior to going in but they put about 1/2 gallon of new 91 in it and rebuilt the stock carb. Could be big part of the problem?
    I bought some Royal Purple Max Octane booster and system cleaner today to see if this helps.

    From what I recal, my stock 525xc that I had prior to selling 5 years ago seemed to pull quite a bit harder and it was stock besides rejetting, boot out and modded stock exhaust.

    Any ideas on what could be going on with power and response and low idle/slow starting?
    I’m going to glamis on the 16th and was gonna call around to a few local shops that have a dyno. Perhaps the tuning is just really off?
    2009 KTM 525 XC
    -KTM Bill Full Exhaust
    -FCI

    -O-Ring Mod, R&D Float Bowl, Emulsion Tube, 41MM Carb
    -CT GNCC Race Package -
    CNC porting of the cylinder head, CNC Radius 5 angle valve job for +1mm over size valves, Set of new +1mm Valves, Performance Lightweight Valve Spring Kit with Titanium Retainers, Webcam 821 Grind Camshaft, Diamond Honed Cylinder and a JE 13:1 Hi Compression Piston
    Dyno: 60.7 HP and 40.3 TQ on VP 110

  6. #5
    Member Rookie
    Join Date
    Oct 2015
    Posts
    46
    Did your first 525 have the rancho mods done? Doesn't sound like this one does. If the first one did and this one doesn't that would be one big difference. When is it hard to start, hot/cold, choke/no choke and was it hard to start before. Assuming it started fine before and your valves are adjusted properly I would say your AFR is off. I didn't really have a close by dyno shop for myself or thats the route I most likely would have taken but I ended up getting my own wideband meter to get it dialed in. Keep in mind I have the rancho mods with HRC needle but when I first set mine up I thought I was good with a 168 main and 3rd clip and with the wideband I am now 2nd clip and 155 main which made a huge difference in throttle response and it I could even tell a difference in how crisp the bike sounds.

  7. #6
    Junior Member Rookie
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    Jan 2020
    Location
    India
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    12
    stock suspension is pretty sweet, but could have been a few inches wider. ... Look good too, but the ltz-450r looks best I think


 

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