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Torque, flat spots, and general tuning

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2005 CRF450X with full uncorking and re-jetting, '05 R cam, DR D pipe, double o-ring apump mod, JD apump diaphram and spring. Stock return spring.

It's been a long time, but I think I have the stock leak jet as well. Can't remember.

I have a noticeable flat spot before the power band kicks in, and I don't believe it to be a lean or rich AP bog. I cannot make it 'AP' bog, so I believe it is at least close in tuning.

The issue I have is I have no real torque below where the power band starts. It runs clean down there, never stumbles, never hesitates, but it has what feels like is about 20 ft/lbs of torque until what I am guessing is 5000 rpms.

I cannot get the front wheel up when I short shift. I have to wait till the revs climb before attempting to loft the wheel.

No Tach, so I have to use these adjectives to describe rpm level.

In contrast, my uncorked but stock WR450 will wheelie just about off idle. Much more like a XR650R power band. It is only about 40 hp, but it must be 30 ft/lbs torque at about 3,000 rpm.

I would like to get a bit more bottom end torque to loft the front wheel, so I don't have to get into the sketchy part of the powerband on single track.

TIA

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i thought that the r cam would have taken care of the low end sluggishness. i have a yz with a wr tranny in it and it will pull up the wheel in a moments notice with no hesitation. i would love for my x to do this also. i feel your pain, unfortunately, i have no idea how to fix it.:worthy:

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hmmm I have an 07 fully uncorked & rejetted to a 165, running thick oring. Stock leak for an '07' is a 70 and I have a 55 that Im going to put in along with the merge spring (and hopefully) dump the oring.

I thought the r-cam was for higher rpm power delievery? Also what about header, I believe they are tuned to the type of power delievery you want... may help.

I do know what your talking about as far as poping the wheel up when short shifting, but I wouldnt say I have a flat spot...

Other then gearing I dont know? would a heavier flywheel or clutch basket help?:worthy:

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Go back to stock cam or like Cubera said, try the stage 1 HotCams.

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Krannie,

I think it is definitely a cam problem. The R cam makes RPM faster, but doesn't have a lot of grunt in low RPM range. The Dr. D pipe works great. I would suggest going back to stock cam as well, and still play with the AP and jetting a bit to see if you can improve it.

I ride a freind's 05R every once in a while, and really notice the difference at bottom end. He went to a short throw throttle tube and that helped quite a bit, although you have to be really careful not to get whisky throttle at the wrong moment.

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You do not lose low end with a R cam, at least I can tell you that I definitely have not. Others that run the R cam will tell you the same. The X cam is anemic all over--even on the bottom--presumable for emissions.

I'm running a R cam, MRD low-mid R header, Yosh can, 170 main, JD red needle, opened up box, pink wire. My bike has zero flat spots anywhere and has way more push top to bottom than a stocker.

+1 on checking the AP setup again.

Does it matter what the load is? How fast you hit it? Has it always done it?

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You do not lose low end with a R cam, at least I can tell you that I definitely have not. Others that run the R cam will tell you the same. The X cam is anemic all over--even on the bottom--presumable for emissions.

I'm running a R cam, MRD low-mid R header, Yosh can, 170 main, JD red needle, opened up box, pink wire. My bike has zero flat spots anywhere and has way more push top to bottom than a stocker.

+1 on checking the AP setup again.

Does it matter what the load is? How fast you hit it? Has it always done it?

Does it matter what the load is?

How fast you hit it? Has it always done it?

It happens only in low rpms, regardless of throttle opening. As you open the thottle more and more, you get less and less, until the revs build. Whacking the throttle changes nothing, unless you pass that certain point where the power band begins, and then the bike stands up immediately. Any place before that and it just honks.

I guess you could say it's a bog, but there is no hesitation; there is just no results.

I really think I need to start over with the AP before changing the cam, that's for sure.

I'm going to take what I learned about the AP circuit on my WR and apply it to the X.

Thanks for all the replies............:worthy:

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What gearing are you running? I was putting the yard with mine yesterday and cracked the throttle in 1st and almost looped the bike. Stock gearing, JD kit and open sides on the airbox. I also tip the scales at 350+ or -. I have found on this bike too that hooking up is hard. I get alot of wheel spin, so I run about 12 psi in the rear tire and seems to help with tractability.

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i think u have over cam'd your X go back to original my stock X has bulk grunt of the bottom compared to my WR. i think the standard long header pipe helps bottom to mid range as well. Are both bikes geared the same?

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i think u have over cam'd your X go back to original my stock X has bulk grunt of the bottom compared to my WR. i think the standard long header pipe helps bottom to mid range as well. Are both bikes geared the same?

Changing to the R cam only changed the bottom end about 5%. It is geared stock, which is lower than my WR is geared.

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5% doessnt sound like much but i'll have 2 extra hp thanks. also wot year is your wr , even though the gearing is lower on the honda, yami lower'ed the primary gear ratio to try save there gearboxes on the later models.

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