EXC to a SX head

[andy 101]

Any one here changed there exc 250 head for a sx head ,have changed mine over but having a problem getting it jetted right, I have a fair idea about the change and have jetted leaner off the exc jetting chart but dont want to jet off the sx chart as I have the needles and jets already for the exc. Just need a base setting to compare to, otherwise ill be spending all weekend changing jets and needles when i should be riding.

[morg_nz]

Any one here changed there exc 250 head for a sx head ,have changed mine over but having a problem getting it jetted right, I have a fair idea about the change and have jetted leaner off the exc jetting chart but dont want to jet off the sx chart as I have the needles and jets already for the exc. Just need a base setting to compare to, otherwise ill be spending all weekend changing jets and needles when i should be riding.

are we taking 2 or four stroke? if four stroke, the head plays a large part in the fuel dynamics in the engine (i.e. flows) so i would say it was more appropriate to jet from an sx chart. however, that also depends what the bore x stroke is for the exc vs the sx. if they have significantly different bore x stroke then you will have to wing it. i'd suggest looking up those specs and seeing what you have different with the sx head so you know what you need to account for.

(also, i may be pointing out the obvious but if you really needed to ride you could always put the exc head back on?)

[andy 101]

are we taking 2 or four stroke? if four stroke, the head plays a large part in the fuel dynamics in the engine (i.e. flows) so i would say it was more appropriate to jet from an sx chart. however, that also depends what the bore x stroke is for the exc vs the sx. if they have significantly different bore x stroke then you will have to wing it. i'd suggest looking up those specs and seeing what you have different with the sx head so you know what you need to account for.

(also, i may be pointing out the obvious but if you really needed to ride you could always put the exc head back on?)

Dont mention four strokes around me, 2 stroke, I have the bike running fairly good awsome torque and smooth power, but keeps on fowling the plug at idle, It is running a bit rich, but I suspect it maybe the colder sparkplug changed from the exc br7es to the colder sx br8ecm.

[noobi]

I assume that you have leaned the pilot out one size? and/or leaned the air screw out to no avail?

[andy 101]

I assume that you have leaned the pilot out one size? and/or leaned the air screw out to no avail?

The pilot is a 38 dont want to lean that anymore, and have turned the air screw all over the place, anyway there is only one size left a 35, the idle and just off idle is great, but sitting there idling it fouwls the plug afther about 3 minites, have also checked float height as well. It just maybe one of thouse ktm sorta things that sort themselves out.

[B0000M]

im yet to see a jetting issue 'sort iself out'

[Pornstar]

Hey dude, Sup with morgnz?, anyway i have been thinkin of doin the same thing to my EXC, how different do ya find as it is now? and how much of an improvement do you Guess? i.e, would you recomend it. cheers

[andy 101]

Hey dude, Sup with morgnz?, anyway i have been thinkin of doin the same thing to my EXC, how different do ya find as it is now? and how much of an improvement do you Guess? i.e, would you recomend it. cheers

The sx head is a big improvment over the stock head and combined with the fmf gnarly pipe is awsome, if you are afther more lowend torque and smooth power I highly recommend the mod, The problem I had was not jetting realated ,but using the sx spark plug, It was to cold and not retaining enough heat to burn of the left over combustoin on the plug at idle, and fowling, seems to of been fixed now using the br7es.

[Pornstar]

cheers for that, its on the to do list, $250 from Austria. Also check out KTMforum UK for good info.