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So first what I got.

I haves a '97 CR250R with a Eric Gorr modded cylinder/pv and head. Vforce reeds and an Airstriker carb.

I also have a '01 CR250R that is stock.

Recently on a ride (on my 01) the bike or my skill set failed me. I'd say it was the bike as when I traded bikes with my buddy, '17 250xcw, I blasted up the climb like it was nothing.

So my question is how close can I get a CR motor to being the KTM 250xcw motor power delivery wise? What else can I do and how good are the end results?

Thanks guys

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I have an 01 CR also,,,two different animals. A heavy FWW, slightly rich jetting and maybe a FMF Gnarly pipe will help but it will never be a KTM-W.  The gear box is a big issue also.

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No. I get it. Just bummed because there's a lot of things I really like about the CR.... power delivery on truly technical trails is not one of them.
Will be ordering a 14oz fww today. I have a KTM 300xcw waiting for me but don't think that will happen before spring. Just going the cheap mod route for now.

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:thumbsup: I truly love my CR here in the flatlands but don't think I would enjoy it at altitude in your singletrack. I use an XR4 when I come to CO for DS.

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I have a 450x but I've been swayed by the weight of the 2 strokes and wanted to turn my CRs into do it all trail/woods bikes. Ordered a 14oz fww today will get it installed Thursday and see what kind of difference it makes. Tired of my 01 making me look bad on technical trails!

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Yes on the mikuni, have a pwk Airstriker as well. 2 motors one modded for woods/endurocross the other stock. 13/50 gearing (also have 48/49/52) . Will be getting a 14oz fww Thursday . Hoping the fww will make it a bit more tractable in gnarly conditions. Running FMF fatty turbine core combo on both CRs. Oh I also have a vforce reed block/boyson reeds/stock reeds and an autoclutch (revlok)

I don't know what else to try after the fww

I have to admit I didn't think it would be so hard turning a MX bike into an off road weapon

 

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I checked the squish on my (sons) stock '01 it was 1.5mm, my first instincts are to turn the base down .5mm if i were looking for more down low.

You need the head done at a minimum.

So you have tried the PWK and the V force? or is that the '97 motor?

Or if you don't want to get into modding the engine try some good oxy fuel like T2 or VPR

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01 motor in 02 frame woods/hare scamble/mx bike.  I run the Gorr 265 with C10 porting, Lectron carb (for ease of use mostly) Boyeson Rad Valve, RB modded head and switch between a stock pipe, FMF Fatty, and FMF Gnarly depending on what kind of riding I'm planning on.  Also run a "shorty" FMF Q Stealth. IMO, the main thing that makes the bike more "flexible" is the Rekluse Z Start Pro. I run it on the hardest and lowest rpm engagement point.  13/50 gearing for MX, 14/50 for everything short of a couple of high speed desert style races where I run 14/47.  Tried the 12, 10 and 8 oz FWW and pretty much settled on the 8.  I spent an afternoon at the track swapping FWW and even going without.  It was very apparent how much better the bike was able to put power to the ground when I put the FWW back on. Personally, I like the 8 as the motor will still spin up quickly when you fan the clutch out of the corners.

 I ride and race with all the newest bikes (which are amazing.....and expensive) and this ole girl holds her own everywhere except top speed on some faster courses.  Limited top speed is probably a safety net for my young mind in an old body.

The way my motor is setup, it just wont die.  Gear to low, it just chugs away and seems to find traction saving my backside time and again. Cartwheel high speed crash, just lays on its side idling waiting for me to re-group and get going again.

With a little trial and error, I'm sure you can find the combo that works well for your use.

Edited by GR250R
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Did a little test ride today with the 14oz fww on the 01 stock MX motor, big difference on the looser fresh tracks I was cutting. Going to take her into some gnar this weekend and see how she does.

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in my experience moving the power around on an MX can help a little to get it to behave better on the trails but the thing that makes mx bikes a handful is the snappiness and hit.  Getting a gnarly pipe or other mods to move power down lower doesn't really help the rideability much.  You still have really snappy instant mid range power that spins the rear wheel up among other things.

You want smooth power that builds more slowly.  On MX bikes it sounds crazy but sometimes the best thing to do is take away some of the mid range power, get a very heavy FFW and put on something like a PC pipe that is more of a top end pipe and a silencer to match.  This will neuter the hit a little bit and allow you to get deeper into the throttle with out getting that bit hit of power in the mid range that breaks your traction and or sends you off line.  Look into adjusting the ignition timing, sometimes retarding the ignition just a hair can help smooth things out a bit.

KTM's are easy to ride through the throttle and rev range, every time i ride a KTM xc it feels gutless until the very top of the rev range, it's just easier to ride a bike like this.  You don't need crazy mid range power to do technical trail riding and can make some serious hills with out a lot of HP especially if you are putting it all to the ground instead of spinning.

I don't know much about the cr powervalves, are they adjustable at all??   I know you can mess with the yz PV a bit and obviously the KTM's are adjustable.  Getting the PV to open later will help smooth out the power in the mid range.

I rode a yz250 built for the woods for many years.  It was a really fun bike but it was too much for certain situations, like stated in OP, i had trouble with gnarly technical hill climbs.  Every time the power would come on it was like trying to keep a wild bucking bronco on a tight rope.  Loved the hit on normal trails and anything else but when it came to those kinds of hill climbs it was to much to handle and left me frustrated.  

Sold it, have a yz250x now, much easier to ride, with a lot smoother power, not quite the arm ripper the normal yz250 was but i feel so much better and faster on it and tackling really gnarly stuff is way easier. :thumbsup:

 

 

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You cant turn a cr250 into a woods weapon that is comparable to an XC-XCW 300 ETC. It will always hit too hard or not hard enough somewhere in the power band. You can get close though. what you will end up doing is adapting your ride skills on an MX bike in the woods. I'm not bragging but I run with the best enduro riders in my area on a modified 02 cr250. Trails, hills, rocks, you name it. MX bikes do work for trails, woods, enduro but As stated, you need to adapt to the type of riding and not so much the bike to the type. good luck

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2 hours ago, mxsteve1968 said:

You cant turn a cr250 into a woods weapon that is comparable to an XC-XCW 300 ETC. It will always hit too hard or not hard enough somewhere in the power band. You can get close though. what you will end up doing is adapting your ride skills on an MX bike in the woods. I'm not bragging but I run with the best enduro riders in my area on a modified 02 cr250. Trails, hills, rocks, you name it. MX bikes do work for trails, woods, enduro but As stated, you need to adapt to the type of riding and not so much the bike to the type. good luck

IMO, the 2002 motor is significantly more adept at woods riding (slow, technical) than the 2001. The 2001 feels like an explosive mid-top hammer compared to the 2002. While you're able to be successful with your 2002, doing the same on the 2001 requires notably more effort. 

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13 hours ago, subxero said:

in my experience moving the power around on an MX can help a little to get it to behave better on the trails but the thing that makes mx bikes a handful is the snappiness and hit.  Getting a gnarly pipe or other mods to move power down lower doesn't really help the rideability much.  You still have really snappy instant mid range power that spins the rear wheel up among other things.

You want smooth power that builds more slowly.  On MX bikes it sounds crazy but sometimes the best thing to do is take away some of the mid range power, get a very heavy FFW and put on something like a PC pipe that is more of a top end pipe and a silencer to match.  This will neuter the hit a little bit and allow you to get deeper into the throttle with out getting that bit hit of power in the mid range that breaks your traction and or sends you off line.  

 

I agree about the part on having the mid range smoothed out for trail woods type riding.  I rode an 07 CR250 with a reconfigured head for lower comp., Gnarly pipe & a FWW back in 2010.  It had smooth torque from off idle with no mid range hit & almost felt like a 4t powerband.   Even though it had a gnarly pipe which is known to kill the topend it actually had good topend power due to the lower comp..  The lower comp. accomplished 2 things it smoothed out the mid range hit & allowed the engine to rev on top.

I believe the new YZ250X has a lower comp head if not mistaken.  Yamaha was probably thinking the same thing about making the YZ250 more trail friendly so they came out with the X model.          

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.

On 9/26/2017 at 8:40 PM, Watige420 said:

Yes on the mikuni, have a pwk Airstriker as well. ......

I don't know what else to try after the fww

Instead of a 38mm, try a 36mm PWK w/ a straight taper needle. It'll get you a nice strong pull down low.

Stick w/ 13:50 gearing for a usable 1st gear.

This is a video of me riding my '05 CR250,  working it through this 30 mile technical woods loop that took us 6 hrs to complete. 30miles divided by 6hrs=5 mph av for the day. THat's 2nd and 3rd gear stuff riding over rocks and roots,  99% riding under the pipe and lugging it.

Go to the 4:00 minute mark, ....that's when my buddy catches up to me ...

...oh, and if you listen closely to my motor, you'd know that I'm running this neat little device that's (imho) made for gnarly rocky root infested mountain goat trails. I'm not skilled enough nor is my finger in shape to keep slipping that clutch for more than a couple hrs tops.

DSC0815.jpg

 

Edited by jeddclampette
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