FMF Fatty on KTM 380, please help with re-jetting!

Ivan K

May 23, 2001
hello friends !

(again, sorry for my bad english)

the other day i finally bought an FMF Fatty Pipe + the Power Core II silencer for my KTM 380 (type: EGS)

how should i change the jetting now ?? PLEASE HELP !!

my actual jetting is the stock-380-EGS-jetting (NO spark arrestor)

(i hope i use the right technical words now, i try to translate it from the ktm-manual)

Carb: keihin PWK 38

Regulation-Number: 080598

Main-Jet: 175 (168, 170, 172)

Idle Jet: 45 (48,50)

Start(?)-Jet: 85

Jet-Needle: R 1472 J (noz G, noz H, Noz I)

Needle position: IV (from top)

Bar: 6

Air-regulation-screw. 1,5 turns open

hope someone can do something with those numbers.

thank you very much for any kind of information

greets from austria - not australia



Jan 12, 2001
The pipe should not affect your jetting too much if it was good before the FMF pipe. To get it just right you will need to get the bike warmed up then do some full speed plug checks. Run the bike up the longest slight uphill you can find in 4th or 5th gear then kill the engine at speed. Pull the spark plug and it should be light tan on the ceramic. Go up or down on the main jet and retest until you see a light tan ceramic. Do the same thing at half throttle to set your needle height.

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