What have I done wrong?

Hi guys,

I had an 2006 CRF 250X that I jetted with the JD kit, Red needle 5 clip, 158/42, AP mode, open air box and an Arrow muffler and head and it was a very nice bike, with lot of low and middle power, not very high rpm but it was ok for technical and slow trails that was I do.

Right now I sold the "old" 2006 and bought a new 2011 (2009) 250X and tried to jet it myself, because I spent all my money on the bike and it's a "little" expensive to buy a new JD kit from the States (I live in Portugal, you know and the crises...).

So, I opened the airbox, maybe a little too much, because I didn't remember what I have done 5 years ago, so I opened all the upper section of the box (I don't know if this is a problem of too much air) and as I have an NCYS needle and saw that many guys use it, I put this needle in, clip 4, and as this 2009 bike has already the 42 slow jet I only change the stock 132 main jet with a 155 one and the pilot screw passed from 1 3/4 out to 2 1/4 out. No AP mode required in this new 2009 bike, I have an Arrow header that has a little larger diameter than stock and use a new Leovince X3 muffler and didn't do the pink wire and I ride sea level to 2000 ft.

Right now what I state: the bike revs very high, it never ends with a very linear, not explosive power and even in 5th gear the bike cuts the ignition off at more than 12.000 rpm (I have an rpm meter) but it has no soul as my old 2006. At low and middle power it's difficult to get the front wheel of the ground.

This is the contrary of what I want, I don't need to do very high rpm but need low power to raise the front to pass roots, rocks and so.

I read in some forum (didn't remember which) that this new 2009 motor has a different top head more like the 250R and maybe because of that I can't find the low end as I expected, but as also the carburetor isn't the same of the old bike, now it's a FCR14B and the stock needle now is the NKKT maybe the NCYS needle and the 2 1/4 out isn't the correct jetting for this 2009 CRF 250X.

Any advice on this matter?

Thanks in advance from this side of the Atlantic.

Best regards.

Miguel Cunha

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im not sure you can get what your looking for with jetting...you might need to change cams to an older X cam

I did not touch the needle on mine. Not quite sure if they are the same. US bikes are different. Mine stock had a 42 pilot, 135 main, and 55 leak. I have done the 3x3 opening in the airbox, 2R racing exhuast tip, 45 pilot, 158 main and kept the 55 leak. I am running the Flex Jet fuel screw 2 turns out. I mainly run my bike in the California desert about 1500' above sea level. My bike runs fantastic and I have no troubles pulling the front wheel in 3rd and 4th gear. I weigh about 175lbs. If you changed your head pipe also that could be part of it. A larger head pipe will cause a slight loss of bottom end, but slight gain on the top.

im not sure you can get what your looking for with jetting...you might need to change cams to an older X cam

Hi, can you confirm what I read that this new 2009 250X model has a cilinder head and new cam, more like the 250R model?

If this is correct, sure I can't get the "old" bottom end power, what explains this new behavior of the 2009 model.

Thanks :smirk:

I did not touch the needle on mine. Not quite sure if they are the same. US bikes are different. Mine stock had a 42 pilot, 135 main, and 55 leak. I have done the 3x3 opening in the airbox, 2R racing exhuast tip, 45 pilot, 158 main and kept the 55 leak. I am running the Flex Jet fuel screw 2 turns out. I mainly run my bike in the California desert about 1500' above sea level. My bike runs fantastic and I have no troubles pulling the front wheel in 3rd and 4th gear. I weigh about 175lbs. If you changed your head pipe also that could be part of it. A larger head pipe will cause a slight loss of bottom end, but slight gain on the top.

Hi, yes I think it's the same bike, because the jets are almost the same, except that my main is a 132 not a 135.

DO you think that I'll get more low end if I put the stock head pipe and change the pilot from 42 to 45 and the fuel screw from 2 1/4 to 2 out?

About the weigh I have 220 lbs, but I had also that with my old 2006 X :smirk:

Thanks :smirk:

Hi, can you confirm what I read that this new 2009 250X model has a cilinder head and new cam, more like the 250R model?

If this is correct, sure I can't get the "old" bottom end power, what explains this new behavior of the 2009 model.

Thanks :smirk:

without looking anything up i can confirm this...im planing to do some top end work to my 05X at some point late summer or early fall and i have been checking on the whole cam head thing

So, maybe I can't do anything to increase that low end power, correct?

Maybe I'll wait to see new posts about this matter.

Thanks :smirk:

i would wait and see some other post as i am not an expert and have only have had my X for like 4 months,i have done quite a bit of research on our bikes though and have been riding dirt bikes or quads for like 30 some odd years,2 strokes , 4strokes and have done most of my own work on all of these bikes,i really dont thing you can adjust your power delivery by jetting alone

Hi, can you confirm what I read that this new 2009 250X model has a cilinder head and new cam, more like the 250R model?

If this is correct, sure I can't get the "old" bottom end power, what explains this new behavior of the 2009 model.

Thanks :smirk:

The head and cam were changed in 08' to be more like the R. Not exactly but closer to. The piston and valves are the same. Here is a good read on the 09' The larger head pipe will kill bottom end.

http://www.dirtrider.com/reviews/dirt_bike/141_0409_honda_crf250x_hop/index.html

Did you ever change the gearing on your old bike? That could make a large difference. I'm not sure if it's stayed the same in all years from Honda but you should look into that.

The head and cam were changed in 08' to be more like the R. Not exactly but closer to. The piston and valves are the same. Here is a good read on the 09' The larger head pipe will kill bottom end.

http://www.dirtrider.com/reviews/dirt_bike/141_0409_honda_crf250x_hop/index.html

Hi, thanks for your input. Maybe this is the "problem", it makes more rpm and more top power but less bottom power, at least this is what I noticed and thought that this could be a jetting issue :smirk:

I'll try with the stock head pipe to see if I notice any improvement.

Regards.

Did you ever change the gearing on your old bike? That could make a large difference. I'm not sure if it's stayed the same in all years from Honda but you should look into that.

Hi, nop, never did that, but you're right, I'll try to see if there is any difference in that matter.

Anyway it could be an improvement if I reduce one tooth in the sprocket.

Regards :smirk:

Did you ever change the gearing on your old bike? That could make a large difference. I'm not sure if it's stayed the same in all years from Honda but you should look into that.

No, I used allways the stock gear: 14/53... and it's the same on the new bike :smirk:

It must be a difference in the motor, I think.

Hi, I know its been like 2 months but did you get your bike running like it should??

Afresh rebuilt "old" X runs as strong as the 08's 09's, At least my butt o meter thinks so. There were changes through the years but not enough to make or break a good deal on a earlier year if you find one. I'm kinda liking the fact they are not changing them much and parts interchange, was sad to see the 2010 R redesigned

The r head pipe is worth a try if you have one handy, I've back to back swapped them and can tell the difference. Power off the bottom is slightly smoother (any loss is hard to tell) and it tucks in better from dents/burns.

<<At low and middle power it's difficult to get the front wheel of the ground. >>

I've left my '09 250X mostly stock. I've only done a JD Kit and opened the airbox and find low to mid power reasonable for a 250.

For the box, all I did was remove the snorkel, then put 6 1" diameter holes in the top.

Do you still have the stock pipe and muffler? If so, I'd bolt it on and see what the difference is.

Gearing is the other place you could go as was suggested. A larger rear sprocket (which I'm considering) would help.

Jim.

Oops...just noticed this was an older thread. I wish the date/time of posts was displayed a little more in our face then it is now.

Jim.

Oops...just noticed this was an older thread. I wish the date/time of posts was displayed a little more in our face then it is now.

Jim.

dont feel bad i have done the same thing

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