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Hare Scrambles Setup CRF 250X - Engine

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Just purchase a new 04 250X yesterday. Looking for input on engine modifications that are worth the cost and effort to set the bike up for hare-scrambles racing. My Honda dealer reccommended the closed course competition kit. I know I have to rejet the bike no matter what but I'm looking for feedback on putting the R cam and the R header on the bike and feedback on which pipe works best with this combination. What are the pros and cons of this configuration Vs leaving the stock Cam and header on the bike and going with a new pipe?

Additional information- the rider is a 115 pound female experienced racer moving up from a YZ 85.

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Congrats on the new ride!!!!

Where are you riding/condition wise and terrain that would be the best starting point to help out to aim set up etc.

You can click on the link in my signature on how I have mine set up, and I ride single track in western washington so roots, rocks average speed for a days run is 12-15 mph so its not wide open for me, but I have taken mine west of here where I did get to bump up to the rev limiter quite a bit and it was wonderful out there too.

My 250X up makes me grin more and more each time I ride it, cant get over how much pure fun it is to take this thing out on the single track.

If you are riding where you want low end, DO NOT change the cam and the pipe, you will loose your bottom end.

Let me know the terrain and conditions and would be happy to help where I can. Had my bike since May and try as I may as well as anyone else that wants to give her a ride, I cant break it. :cry:

No valve issues, no oil burning, starts first lick and just makes me grin!

HR

:cry:

:cry:

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I would have to say as a former x owner that did the cc mods as well as powernow ,twin air powerflow kit,r exhaust ,the bike had more get up a go.But at my skill level in tight wooded areas the bike lost some of its smoothness I enjoyed while it was stock.I would definitely ride it for awhile so you have a good baseline for any mods you do.

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Located in Nothern California. Sea level to 3000 feet covers most of our riding. Most of the racing is in spring and fall but temps are still in the 90's. The race courses vary from black diamond terrian to 5th gear wide open portions and ususlly involve part of a local motocross track.

I understand the stock cam will tend to give me more bottom end tourque but I'm trying to get feedback how much is lost on the bottem with the R cam. Also, from what I've read some header and pipe combinations work much better on the X than others. Also, California has some pretty tough sound regulations so a pipe under 96 db is a must.

It looks like you have left you bike stock when it comes to the the cam and pipe configurations.

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I agree with doing what is called the free mods first and run it and see where you want to move the power around and in what direction.

All of the after market exhaust systems have NO gain on the stock systems until about 7-8000 and up. For me I am rarely there and the electric drill smoothness of the motor and exhaust combo cant be beat and I am a 100 pounds + more than your rider.

Of my friends that have changed just the exhaust/silencer the FMF appears to have the most gains and stays under 96. Again you are not going to gain any bottom over stock until mid RPMs, you can check dyno runs etc.

I would focus on getting the jetting totally wired, add a power now for more response and off bottom uggmphf etc and just see. This bike will sing with a 115 pound rider. Going to just an after market silencer and leaving the headpipe alone you wont loose any bottom (in most cases and gain a health shot up top without loosing the good bottom with the stock header.

Another thing I would do before even considering changing the header is a +.75 compression piston and if you still need more (which both will give you big gains across the band) is having the head polished and flowed etc. Way way cheaper than an after market pipe system and honestly just the piston will give you better gains across the entire spread than any pipe will.

Now given the weight of the rider, the stock suspension will be way to stiff.

Valving in the X is pretty awesome so get the springs matched and play with the clickers and I think you will be very happy.

Good luck

HR

:cry:

:cry:

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I also have a 04 X. I race supermoto and HS in northern californaia and generally ride sealevel to about 3500. The jetting I have found to work the best is, 55leak, 42pilot, 152 main, and the CCC needle on the 3rd clip. Have a Dr.D exhaust, cut airbox, cut pink wire and also removed the smog pump. My bike feels great, I run it on 110VP mixed half with 91 premium. Dont forget to get a good skid plate and radiator gurards. I learned my lesson the hard way, took a slow spill and bent/popped a radiator. Since I am running rooster guards and I have taken some nasty falls and they are still holdingup no prob.

I would wait for the Hot Cams to comeout before throwing in the R cam, generally hotcams are loosing no bottom end at all and gaining a bunch up top.

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Another thing, instead of consentrating solely on HP make sure your suspension is dialed and the bike is set up for you. I know that after getting new bars and footpegs as well as re-doing the suspension I was way faster because I wasnt tired after the race due to being uncomfortable.

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My son has raced a 2004X since the first release and he also came from the mini's(2003 CR85 Bigwheel).Power is not an issue.Stock pipe and cam,TwinAir filter conversion, partially cut air box, 42 pilot-150 main, Zip-Ty fuel screw.He weighs about 155 and rides at 2600 ft. here in the east.Can almost always get the hole-shot against 450's with dead engine starts.Only issue is lifting the bike up after a fall.Using Michelin S-12's which for us outlast the Dunlops about 3 to 1.Buy rad guards and skid plate.The switch from 2-smoke to this bike was a big jump for a kid, but now he just gets that stupid grin every time he rides or races it.Currently 4th in D5 HS points against all size bikes (4 stroke class) and all older men.(He's 14).Good luck to you and your daughter-she will just love that bike. :cry:

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You've gotten good advice here, Especially from Jimmy and HR. A couple of thoughts;

- The bike is tall and heavy for a 115 lb rider. Hopefully your daughter is tall and fairly strong. I've been all through this stuff with my wife who was the top women rider in the PNWMA series hare scrambles and CC's for three years in a row, as well as my 13 yo son (5'3", 120 lbs) racing Junior Under in the PNWMA this year.

Anyway, as far as the 250X goes, I would add the following comments;

- The X suspension is magic. Valving is the best I've ever experienced. Only bike I've ridden that was even close was a 2001 Gas Gas 250EC.

- The electric start will be a huge bonus for your daughter. Best 8 lbs you could ever cary.

- This bike is the easiest and most effortless bike to ride ever. Saving energy means you can ride closer to your max speed longer. Other bikes that are easy to ride are mostly limited by extreme weight issues, twitchy handling at speed or really limited power.

As far as mods go, I would agree that you should try the free stuff first. 42 Pilot, 155 main, 2.25 turns on the fuel screw, 4th position on the needle, open the airbox. IF after riding it a few times she needs more power I would suggest the R cam and pink wire mods, but DON'T use the R header (too much low end power loss). The R cam doesn't lose that much down low, but the R header does. I suspect that if you're using the R cam, you'll need to lose the baffle. The bike gets loud without the baffle so if you want to retain the quietness, try the FMF Q silencer. This is the set-up I think I'll try in the spring. Mind you, I weigh 190 lbs (on a good day!), not 115 lbs, so you may not need to worry about any more power.

good luck

Dave

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Thanks to everyone for your advice.

Decided to apply the KIS priciple. I'm going to stick with the X cam but bolt on a Dr. D sytem with the quite core. Everyone seems to rave about this system and it will meet the 96db issue in California. Already have extra jets and needle valves on order.

A number of you mentioned suspension issues. I already had that issue covered so I didn't touch on it in this thread. I'm taking the bike to my local mx suspension spealist to have the bike lowered 2 inches, resprung, and revalved for my 115 lb. 5'3" rider. Other accessories will include stablizer, tripple clamps, radiator guards, skid plate, avs levers, and hand guards.

Our goal is to get some seat time in the last 1-2 Womens C races this fall. She'll continue to ride in the regular 85 C class and continue to kick some more boy butt as well. " A very proud dad speaking here"

Thanks again for your advice!

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Cool sounds good. If you need any set up help/tips I will be at the HS at metcalf this weekend and almost all the other ones. Good luck. I am riding the X with the R front plate number 676 if you want to swing by and say hi and check out the exhaust.

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Thanks for the offer but I'll be in Canada this weekend. My wife is going to go with a friend and she gets to be pit mom on Sunday.

Our goal is to enter the womens C race at Prarie City in November.

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