FCRMX-39 jet needles

[steveyb]

Gidday. I am in need of a jet needle or two that are richer than the standard one that comes with the carb in the KTM 250SXF 2007 carb.
Standard is OBETP, want a couple that are richer all over, esp in the early throttle response area, such as an OBEKP or OCEMR(?).
Would also be keen on richer idle jet too.
Anyone have anything?
Cheers

Steve

[scott411]

trying to think of someone that campaigned one of these bikes around that time that would likely have needles MXers tend not to jet anywhere near as much as road race guys do, and in the time of racing four strokes wth FCR's i can never remeber selling needles to anyone,

if I come up with someone, ill get hold of you,

have you tried sudco?

[steveyb]

Cheers Scott.
Have not tried Sudco yet.

[husaberg]

Cheers Scott.
Have not tried Sudco yet.

Steve maybe try to go through the parts fiche of other makes models that carried the same basic carb
It is fairly generic so there will be a different range.
I know Wob had a play with them as part of the TSS500 so its highly likely he has some about the place.
I think he may have even said some of the PWK stuff is compatible?



Of course the needle are pretty much tapered bits of alloy
Someone on the GPR team would be able to clock and make what you want on a CNC.
We had a model makers lathe a Unimat about the size of a printer that was great for fiddly stuff like that but bloody tedious
I have seen people desperate spin them in a drill and sandpaper in the areas they want to richer thinner

[scott411]

unless the KTM ones are way different to the Kaw/Suz ones PWK stuff was a lot different, infact about a 1/3rd shorter in length than the PWK needles,

all of the early 250F's ran a version of the FCR 39, but needles vary massively, and if you only want a small change then it may be better sticking with the KTM series of needles,
adjustable leak jets where the go for the MX bikes, to help tune the bottom end tuning, either with a whole carb bowl, or a merge racing accelerator pump cover, MR Motorcylces will have some of them left as i brought a number in and when the bikes all went to injection they were not popular anymore,

[Pornstar]

https://www.jdjetting.com/xcart/prod...5&cat=7&page=1
I have just put a JD kit into my EXC 250 2t, worth the money dude.

[husaberg]

unless the KTM ones are way different to the Kaw/Suz ones PWK stuff was a lot different, infact about a 1/3rd shorter in length than the PWK needles,

all of the early 250F's ran a version of the FCR 39, but needles vary massively, and if you only want a small change then it may be better sticking with the KTM series of needles,
adjustable leak jets where the go for the MX bikes, to help tune the bottom end tuning, either with a whole carb bowl, or a merge racing accelerator pump cover, MR Motorcylces will have some of them left as i brought a number in and when the bikes all went to injection they were not popular anymore,

looks like I misunderstood what he said. whoops

All the FCR carbs will work fine on a 2T.
The shroud in the carb bore is the same, as are all the air/fuel circuits the same as a PWK etc, but the FCR has an extra idle fuel jet ( screw adjustable).
The emulsion tube is removeable but is a fixed size.
All the adjustment is done on the needle dia, taper angle and taper start point - as are all Keihin 2T carbs.
To get the standard range of needles to work on a 2T the tube has to be reamed out, as all the 4T setups are very lean.

TeeZee, forget the twats saying detune the GP125 - forget your thoughts on doing anything else at all - make it reliable.
At 30 Hp its fast enough to win anything.
The power being made didnt affect the piston falling into the too wide EX, the power being made didnt overadvance the midrange timing, the power didnt make the ring pin fall out - etc etc

[Pornstar]

Ok so this is my bike with the JD kit. from 1st gear tight stuff do you notice any bogs or throat clearing? its smooth as baby.

[pete.ktm]

Ok so this is my bike with the JD kit.

sounds good to me but hard to guess the revs/throttle position from the vid.

you try the suzuki needles? i went that way on my 300 instead of the JD kit. i only had it for 1 ride before i dicked with the jetting so waiting for a mate who has had 300's forever to have a ride to confirm it's all good.

[Pornstar]

Mate, seriously, the JD kit actually has some great R&D in their needle design, its not just a regular needle, its multi tapered.

[pete.ktm]

Mate, seriously, the JD kit actually has some great R&D in their needle design, its not just a regular needle, its multi tapered.

the suzuki needle has three tapers. seems to be more popular than the JD kit but maybe it's coz it's cheaper. put a JD in my 450 and it ran pretty shitty but might have been an exception as people are usually pretty happy with them.

[Pornstar]

Deffo cheaper, mine around $120, next up is the v force 4 reed block

[Factoryjohn]

Gidday. I am in need of a jet needle or two that are richer than the standard one that comes with the carb in the KTM 250SXF 2007 carb.
Standard is OBETP, want a couple that are richer all over, esp in the early throttle response area, such as an OBEKP or OCEMR(?).
Would also be keen on richer idle jet too.
Anyone have anything?
Cheers

Steve

I've got a JD kit for your bike sitting in my cupboard if you're interested

[Stylo]

Seems things were a little simpler back in the analogue days. First trick with my new KX500's was simply drop the needle a couple of clicks from factory and, you're good to go. They always delivered them very rich, must have been a safety thing I guess.

[Pornstar]

Seems things were a little simpler back in the analogue days. First trick with my new KX500's was simply drop the needle a couple of clicks from factory and, you're good to go. They always delivered them very rich, must have been a safety thing I guess.

This is still analogue, just a better designed analogue. same goes for the v force 4 reed block i got comin for it, same basic principle, just more advanced design offering improved performance for my girl.