YZ450F or YZ250F for Woods Riding


43 replies to this topic
  • briangriff321

Posted April 06, 2012 - 03:45 AM

#21

Was it this one ?
Posted Image

  • SleepyHeadYZF

Posted April 06, 2012 - 09:11 AM

#22

I'm afraid that the 250F will not have the torque that I need.


I put an Athena 290 kit, ported and polished head, and custom cams in my YZ250f and I have plenty of torque. But I run out of bike out in the open (13-48).

  • Yamiryder

Posted April 06, 2012 - 04:20 PM

#23

My WR will boil under those conditions.

We are doing mostly 2nd and 3rd gear riding, hard on the throttle.

You're saying your WR boiled over doing 2nd and 3rd gear riding?

  • RiderX

Posted April 06, 2012 - 05:47 PM

#24

I've ridden my 09 YZ450F off road only for about a year now. By buddy rides an 02 YZ250F that has a 290 kit, custom cams, exhaust, a lot of head work, etc, all focused on making more low end power for off road riding. Once he got a ride on my YZ450F he was shocked at the power difference. The weight is a little noticeble in the tight stuff, but you'll have to decide whether you can give up the power for the weight. I've ridden my buddies modded 250F bike quite a few times, and it doesn't even compare in the power dept. If your local riding area is only 10% super tight woods, then it makes sense to have the 450F. If it's 90% super tight woods, then the lighter, less powerful 250F makes more sense.

And FWIW I haven't had any overheating issues.

And to the issue of running coolant with a higher boiling point: this will help your bike stay cool in the sense that it will help prevent coolant loss. Once you boil over you're losing cooling capacity and also putting air pockets in your cooling system which just causes it to heat up even quicker.

  • idahoexcr500

Posted April 09, 2012 - 07:43 AM

#25

I have an 07 YZ450F and ride with a buddy who has an 09 WR450. BTW, my son has an 06 CRF250X too. I have ridden all of them in the woods here in the Boise area (Idaho City) in the summer on some very warm days. Never had any overheating issues with my YZF. No estart is a bummer sometimes and I need to gear it down a little (1 or 2 teeth larger rear sprocket). But even with stock gearing the bike does fine. The WR feels 50 lbs heavier, suspension is like a pillow and the motor is very soft on mid and high RPM power. I like the YZF alot better (as does my friend with the WR). After he rode my YZF he felt he made a mistake buying the WR. His biggest complaint with the WR is the weight difference.
My son's X is really good in the tight stuff. Its very snappy and has allot of bottom end power. I would take it for woods riding over the WR but prefer the YZF overall. I'm 6'4" and 180 lbs so the 250 lacks power for me.Its a great bike though.

  • Navaho6

Posted April 11, 2012 - 05:53 PM

#26

Was it this one ?
Posted Image


Yep.

I rode a 450 last weekend. I'm now thinking the 250 might be less tiring. The 450 is good but I need to compare with the smaller bike.

  • Navaho6

Posted April 11, 2012 - 05:58 PM

#27

You're saying your WR boiled over doing 2nd and 3rd gear riding?


Yes but only when at race pace.

  • briangriff321

Posted April 12, 2012 - 05:36 AM

#28

Well that was my bike...only my third time putting it in the woods

  • Navaho6

Posted April 12, 2012 - 03:56 PM

#29

Well, how are you liking it for that application? How does it compare to other bikes you have raced? Was it good in the tight sections at Ft Polk?

The '09 that I rode would have needed a lot of suspension work and steering damper to be decent in the roots, and lower gearing to be as good as my WR is in the nasty tight sections.

Edited by Navaho6, April 12, 2012 - 05:43 PM.


  • Phineas7

Posted April 13, 2012 - 04:53 AM

#30

I wish I could go back to a 2-stroke. That would be easy but all of them make my hands go numb almost instantly. I had a 300exc which gave me carpal tunnel and ended my riding for 2 years.

It has to be a 4-stroke.

So, is there anything you can do to lessen the flame-outs? My WR rarely does it. When I do stall it, most of the time it is due to rider error.


Have you considered a 200? I've had a couple of 300's, used to ride them just off the bottom, if the revs got up, the vibration was brutal. I've tried riding a 250f in the single track. I guess I wasn't fast enough to keep it cool and prevent flame outs. Love my YZ450 on the track, in the woods it's a heavy, over-powered beast. Bought a 200xc for single track and it's been perfect for me. No paint mixer vibration, lite, doesn't overheat, doesn't stall, doesn't flame-out and way more power than I ever dreamed could come from a 200.

Regards,

P7

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  • briangriff321

Posted April 13, 2012 - 05:21 AM

#31

The suspension on my bike is all stock...springs and everything so itssprung a little to heavy but in the woods its way smoother then my kx250 i had with suspension work....i won first at the first lacc race( first time in the woods) raced the 9 hr on it and put in some impressive times for being extremely slow on a mx track but rolling through the woods....the tighter stuff was a little difficult but only cause i still have full width bars ( thank god for steering stabilizer) it does have a little push in the front end but like i said its still all stock and can be corrected with a little change of body position

  • Yamiryder

Posted April 13, 2012 - 04:37 PM

#32

Yes but only when at race pace.

Hmm, you must have been gettin' it.

  • Navaho6

Posted April 13, 2012 - 07:54 PM

#33

Two things contribute to the overheating, 85F temps or higher and the aluminum radiator guards (they need to come off for the warmer weather). I don't remember the WR boiling as often with the oem deflectors. My WR still runs cool compared to my buddies Husaberg 570. I heard his bike still bubbling 20 minutes after we stopped riding. His fan runs constantly. Before he installed a heat shield under his tank, the gas would boil. Fried his original fuel pump.


Rode a 200 KTM with flex bars. It was worse than the 250xcw. Couldn't feel my hands after 15 minutes. Rode a 300 gas gas and 200 gas gas. The latter was quite smooth, smoothest 2-stroke I've ever ridden and quite torquey. I could almost live with the Gas Gas 200.

There is still no doubt that all 2-strokes irritate the nerves in my hands. The vibes are a lot more intense than all of the 4-strokes I've tried. The smoothest bike in that regard is the KTM 400 xcw.

Been giving this a lot of thought and I'm not convince that I should go the YZ route. I am going to try a newer model ('09) WR450 Sunday. I know I will have to spend some $ on the suspension, but I would have to do the same on a YZ. The weight and soft suspension of the WR can be a benefit in the roots. The YZ I rode was skipping all over the place in the roots but it was easier to move side to side and was much more fun to jump. The WR's wide ratio tranny is really nice for our woods. I don't know that I could get use to the YZ in the super tight thickets that we ride.

Edited by Navaho6, April 13, 2012 - 08:05 PM.


  • RiderX

Posted April 14, 2012 - 07:28 AM

#34

With a good revalve, the correct springs, and an 18" rear the YZ will be just as good over roots. I just can't imagine having a heavier bike than a YZ450 in tight woods.

  • YamaLink

Posted April 16, 2012 - 07:19 AM

#35

I get good results on a 250F with minor gearing change and maybe a pipe while trying to keep the sound levels low. Also proper jetting, if applicable. If the trail ride is over an hour or two I'm much better off on a 250F like others seem to be.

  • Navaho6

Posted April 16, 2012 - 02:48 PM

#36

With a good revalve, the correct springs, and an 18" rear the YZ will be just as good over roots. I just can't imagine having a heavier bike than a YZ450 in tight woods.


That and maybe a WR tranny for our woods. I rode the YZ and WR back to back. It suprised me that the YZ wasn't much faster than the WR. Certainly not as fast as I thought it would be.

I added it all up and the YZ was not the best starting point for what I'm trying to do. So I bought an barely used '09 WR yesterday that has alread been uncorked and has a YZ exhaust. It was a good deal at $3,300 and all it needs is a fork spring change and revalve. If I want to shed some weight off the WR, I can start pulling things off but that electric starter comes in handy sometimes.

Edited by Navaho6, April 16, 2012 - 02:49 PM.


  • Wiz636

Posted April 18, 2012 - 07:08 AM

#37

I would definitely go with a 450 over a 250F for the woods. The 450's smooth, strong power down low is perfect for the woods. Resist the urge to gear it down...all that will do is make the power jerky and over-sensitive to small modulations of the throttle. It also decreases the ratio spread between gears so you need to shift more. Above all, it makes you slower.

If you are in 2nd & 3rd gear you will NOT overheat a YZ450 no matter what pace you are riding. For coolant, forget the expensive aftermarket stuff. Mix up a batch of 80% [color=#FF0000] 20%[/color]ethyl glycol coolant, 20% [color=#FF0000]80%[/color] water, and a couple capfuls of Redline water wetter into a gallon container. This can all be found at a NAPA auto parts store and for less than $20 you will have enough coolant to do a few bikes. The EG lubricates and prevents boil over, the water does the majority of the cooling, and the water wetter breaks the surface tension of the liquid and allows better heat transfer from the cylinder walls into the coolant. I run this in my YZ450 and NEVER boil over even in the tightest woods...as long as you keep the bike moving it will be fine. Meanwhile, my friends on their orange bikes (both two and four stroke) are stinking up the woods with boiled over coolant.

Throw a flywheel weight on it an go tear it up!

For the guy that poked a hole in his radiator and ran on just what was in the cylinder...please explain to me how the coolant remained in the cylinder?

Edited by Wiz636, April 18, 2012 - 08:47 AM.


  • grayracer513

Posted April 18, 2012 - 08:09 AM

#38

For coolant, forget the expensive aftermarket stuff. Mix up a batch of 80% ethyl glycol coolant, 20% water, and a couple capfuls of Redline water wetter into a gallon container.


Hey, Pete, good to hear from you again.

Clear something up for me, if you don't mind. As I recall, your coolant recipe was 20% EG and 80% distilled water plus the wetter. Am I remembering wrong, or did you reverse it here?

  • Wiz636

Posted April 18, 2012 - 08:43 AM

#39

Hey, Pete, good to hear from you again.

Clear something up for me, if you don't mind. As I recall, your coolant recipe was 20% EG and 80% distilled water plus the wetter. Am I remembering wrong, or did you reverse it here?


Whoops...nice catch! As you mentioned, it should be 80% water and 20% EG!

  • shrubitup

Posted April 18, 2012 - 09:06 AM

#40

My YZ250F weren't bad in the woods but I ran out of patience with the carb bog. Could have installed a power bowl and Tokyo mods but I went to a Yamaha demo days and rode all the bikes on the same course. It showed that for me the best bike was the 250 smoker so I went out and bought three of them. :thumbsup: It was surprising coz I dumped the smokers in favor of the 250F just two years ago. :thumbsup: I hear ya on the numb hands. Seems standard bars on my low compression 02 CR250 produces a smooth ride. :thumbsup:

Without a FWW my 250F stalled constantly on tech trails. It was jetted rich so that made it run cooler but was a PIA to hot start. Only time I ever boiled over was climbing high alpine trails when it was above 90*F air temp. Used a 1.6 cap and regular 50/50 coolant.





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