[chippy]

I am wanting to try a Power Bomb header with the Q-4 silencer. The only real mods to my 250x are the J.E. high comp. piston, pink wire, o-ring and air-box mods. I am currently running the stock exhaust with the diffuser drilled out. I am trying to find a little more power in the mid/upper range without loosing the strong bottom end. Anyone else try this exhaust? Am I wasting my money?

[taylorcraft]

I have similar mods only I have a mega bomb header and a Powercore can probably not much difference. This REALLY woke up the motor. Have you rejetted since you opened up the airbox you will need to if you go with the better flowing exhaust. I have heard of people with these mods using main jets anywhere from 145 to 170 and using a 42 pilot (stock is 40) also drop the needle one notch. Better yet buy the JD jetting kit.
The motor ran just fine on the bottom and gained a lot of mid and top. Until the intake valves tightened up, nothing to due with the mods.
I have since gone to an 09-08 R head and cam with great results.
Spend the money for the mods it makes it a different bike.

[chippy]

Yes, I have re-jetted along with these mods. I have also replaced the intake valves with stainless steel. I plan to re-check the jetting and adjust as needed. I am very meticulous when it comes to jetting my bikes. They have to be as close to perfect as possible. It really pays off with the 250x. That off idle hesitation it came with was awful! Thanks for the info.

[Deanzo]

If your off idle hesitation is sorted, then yea, you may be wasting your money imo (though that would never stop me changing out parts lol)

3 best things I have done to my bike (and the list of mods is getting long)

1: JD Jetting with a FMF 4.1 and stock header (note my stock can was toast and had to be changed)

2: Front and rear springs

3: 08 R Cam


Knowing what I know now, if it was me, I'd change the Cam before doing anything else to your bike.
It helps everywhere.
A little bit more on the bottom, great mid range that keeps building into the top.
Power wise, number one mod for me to date.
I also have a JE High Comp Piston, Pink Wire mod etc etc

[taylorcraft]

Good move with the valves, I put alloy seats in with Del West intakes and KW exhausts. 55 hours on that head and the valves have not moved.

[chippy]

Yeah, I put Kibblewhite SS intake valves in and had the seats re-cut. The entire head was cleaned and re-worked a bit. New springs and keepers of course. ;^) My intakes had 100 hours without moving, but I did freshen up the piston.
Deanzo - +1 on suspension springs! The absolute best mod I have ever made to any bike! Night and day difference in performance.
I would like to try the 08 "R" cam. It would be nice to get a complete cam/gear/comp release set up for an easy assembly swap. Can you find them for sale like that? How about the Hotcams set up? Comparable? Better?
Thanks Guys,
Chip

[Deanzo]

The 08 R Cam is almost a drop in part (almost)

You do need to buy this http://www.crfsonly.com/catalog/product ... ts_id/3376

After you take the cam out, change the buckets (look out for the shims so they dont drop in the motor)

Undo the little bolt at the end of the X Cam, take off the de-comp stuff, pull off the rear bearing radial ball.

Fit to the new 08 R Cam using the spring out of the kit I listed.

It is Super easy.


As I understand it from Ken (poor guy got soo many e-mails from me as I was making up my mind) Hot cam 1 great for bottom end, hot cam 2 great for top end.
The 08 R wont give you the same as bottom as a 1 or top like a 2.
But will give you a little more bottom than the X cam, much, much! better mid and a good top.
Which is what I (and sounds like you) was after.
I'm very happy with it.
But check with Ken, he was a big help.


Edit:
One other thing, if you click on my garage/bike, I have a picture of both Cams side by side.
You can see how easy it is/would be to swap the few parts you have to. Hard to tell in the pictures, but the lobes are very different.

[chippy]

So the valve buckets are different? Decompressor spring is different? I do already have the KW springs installed. I am assuming this kit makes the R cam compatible to the X head?

[Deanzo]

Yes, thats my understanding.


As I understand it, even if you stay with the X head, or go with the R head as I did.
The spring and buckets you have, wont work with the R Cam.

I never really looked to see what was different, Ken said I needed to change them if I wanted to use the R Cam, so I did lol

PM Ken, he'll be able to tell you why.

[Deanzo]

If you do go this way, will be very keen to hear how you find it,
taylorcraft may have so input on the below as he has the 08R Cam

What I always found with the stock X
The Bottom end was good and strong but as the RPM's got mid way, I was only really making noise, the speed would build very slow.
If I was going up hill, or trying to get more speed for a jump, the gear up would bog me down a little as it was a little tall for the RPM and how fast I needed to get to whatever speed was needed.
With the 08 R Cam, in that same mid (and higher) RPM's in that same gear, it's still pulling hard and building speed nice and fast, it's only in the top RPM's it drops off, the same as it did for me on the stock X Cam moving from Bottom to Mid RPM's
With the R Cam I now hold the gear longer, build speed much faster and when I do change up my RPMs are higher and it just keeps going till I run out of gearing/or I'm in the very top RPM range.
The added RPM's of the R Map, only really makes noise with this Cam.
I was (taking into account this is not an MX bike) somewhat fast to around 60Kmph, ok to 80kmph, dead slow to 120Kmph.
Now, fast to 100kmph, ok to 110kmph, dead slow to 120kmph.

I have a Vapor on my bike, and played around a fair bit.


One other note, I drink way more gas now.
I now ride in the mid and high RPM's all the time, the bike is just too much fun when riden like that

[chippy]

Thanks for the info.
I think going the "R" cam route may get the results I am looking for. At one time I considered the big bore kit, but decided against that. I hear they can make carburation at altitude much more finicky. I don't need that. I just wonder, since I have the original 04 X head, if maybe an earlier model "R" cam may be better? I am not planning on buying an 08 "R" head just yet. I will save that for my next round of valve work. (hopefully not too soon!)

[Deanzo]

I was very close to going the big bore 280 kit this time round.
But went the the cheaper JE High Comp.

Now not sure I could go the big bore, as I understand it, on top of "some" having jetting issues, hard start issues (never sure if thats just them doing something wrong or a real issue) it moves the power much lower, and I soo like the way the bike feels now, to what it was, and fits the way I ride.

And on top of that, I have now had a really good go on my mates YZ250FX (on the track I ride all the time), and even with all my mods, my X is light years behind his FX.
Now I feel like I'm just wasting money for small gains, as it's not even close

Please Honda, update the X with about 10 more HP and FI! Oh, and don't put air forks on it lol

[chippy]

+1 on the Yamaha. If I had the funds, I would be riding a new Yamaha!

[mac2]

sorry to jump on this,but ive got a 09 R cam i'm wanting to put in my '11 X.

Whats the difference in the decomp spring?

I thought i just needed to change the inlet valve springs?