YZ250F verses YZ450F


12 replies to this topic
  • mnmbb01

Posted January 29, 2005 - 03:15 PM

#1

I currently am running a YZ250f '05 for woods, Enduro's, Harescrambles and really like the bike. I am considering a YZ450 next. Can someone give me a comparisson between the two. Will the 450 be a monster in the woods or can I lug it like a tractor. My best ridding bud runs a KTM 450EXC and could not be happier. I need to ride his to compare with my YZ but its been over a year since I rode his. Anyway, I'm not interested in a KTM 450, I'm interested in a YZ450. What do you guys think? Can you tell me some differences that I might encounter, good or bad. I am concerned that the 4 speed gear box may be to limiting.
__________________

  • grayracer513

Posted January 29, 2005 - 03:30 PM

#2

It all depends, as far as the 4 speed goes. You can drop the gearing some to make it lower, but the thing to realize is that the 4 speed covers just about the same speed range as the YZ426's 5 speed did, or the 5 speeds of other MX bikes, with wider gear spacing and less shifting. Mine is geared sligthly higher than stock (2 teeth off the rear) which puts first gear exactly where the 426 1st is, and fourth is about 2/3 of the way up between the 426 4th and 5th. Riding tighter trails with this setup is a little tricky, but it works.

You'll have plenty of low speed power, especially compared to a 250F, but if you're planning to do a lot of low speed stuff, you'll want to add weight to the flywheel to keep it from stalling when lugging down. The 8oz weld on weights work well.

Another thing you could do as a mod would be to spend $700 on a WR transmission. You would have a lower low, the same 2,3,& 4, and then 5th on top. Pretty cool.

They're a bit of a handful in the woods, but not really in the "monster" category.

  • Matt96xr6

Posted January 29, 2005 - 04:28 PM

#3

It all depends, as far as the 4 speed goes. ...but the thing to realize is that the 4 speed covers just about the same speed range as the YZ426's 5 speed did, or the 5 speeds of other MX bikes, with wider gear spacing and less shifting.


This is not correct.

Look at the gear ratios of the 426 vs the 450:

Gear Ratio - 1st Gear

24/13 (1.846)

27/14 (1.929)

Gear Ratio - 2nd Gear

23/15 (1.533)

25/16 (1.563)

Gear Ratio - 3rd Gear

23/18 (1.278)

23/18 (1.278)

Gear Ratio - 4th Gear

24/22 (1.091)

21/20 (1.050)



Now add the 5th gear ratio of the 426:
20/21 (0.952)

So the 426 has a lower first gear and a taller 5th gear (basically overdrive). The 426 is WAY MORE Wide Ratio compared to the 450 4sp gear box.

  • mnmbb01

Posted January 29, 2005 - 06:42 PM

#4

I've owned two 250 two strokes which were actually very good in the woods and were very powerful machine. I am finding on the yz250F I would like a little more bottom pull. Once it hits the midrange it will fly. Also I wouldn't mind owning one of the most powerful machines out there at least once in this short life but I dont want something that will not be fun to ride. Thanks for the input.

  • YZ250F_Rider

Posted January 29, 2005 - 09:48 PM

#5

I'm selling my 05 450 for the very reason you want one. It pulls like a tractor, and I prefer the midrange hit of the 250. But the 450 is a very stable bike at low rpms, and is just as easy to ride in the woods as the 250 is. It doesnt have any more tendency to stall than the 250 does. And for climbing up hills it far outpulls the 250.

  • grayracer513

Posted January 29, 2005 - 11:36 PM

#6

This is not correct.

Look at the gear ratios of the 426 vs the 450:

Gear Ratio - 1st Gear

24/13 (1.846)

27/14 (1.929)

Gear Ratio - 2nd Gear

23/15 (1.533)

25/16 (1.563)

Gear Ratio - 3rd Gear

23/18 (1.278)

23/18 (1.278)

Gear Ratio - 4th Gear

24/22 (1.091)

21/20 (1.050)



Now add the 5th gear ratio of the 426:
20/21 (0.952)

So the 426 has a lower first gear and a taller 5th gear (basically overdrive). The 426 is WAY MORE Wide Ratio compared to the 450 4sp gear box.

I see that the second ratio in each gear speed you have posted is that of the 450. Note that the 1.929:1 ratio of the 450 is actually lower than the 426's 1.846:1. I'ts higher numerically, but that makes it a lower gear. The 426 has an overall ratio in 1st gear of 17.84:1 and the stock 450, 18.64:1, a lower ratio.

By gearing mine with a 15/49, which is the same as 14/46, or 2 teeth off stock, I now have an overall first gear of 17.76:1, nearly the same as the 426. My fourth gear then falls at 9.67:1, which is about 65% up between the 426's 4th and 5th overall ratios of 10.54:1, and 9.20:1.

The 426s overall ratios are (rounded) 17.8, 14.3, 12.3, 10.5, & 9.2
My 450s overall ratios are (rounded) 17.8, 14.4, 11.8, & 9.7

The four speed is clearly wider spaced.

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  • Matt96xr6

Posted January 30, 2005 - 07:53 AM

#7

the 5sp will always be a wider ratio over all 5 gears than a 4 sp. It is way more versatile for offraod.

If you gear the 4sp for low speed, you lose top end. If you gear the 4sp to match the top speed of the 5sp, you lose low end. It is always a compromise there. The 5sp is probably why Honda has outsold Yamaha in the 450s cause not everyone wants the bike for MX.

Also run the stock gear ratios on a 426 in your calculations: 14/48. Most I know run a 14/50-52 on there. Compare apples to apples. I dont know of anyone running a 46 on the rear for more top speed.

  • grayracer513

Posted January 30, 2005 - 09:17 AM

#8

the 5sp will always be a wider ratio over all 5 gears than a 4 sp. It is way more versatile for offraod.

The YZ426 5 speed is wider 1st to 5th, but the point is that it isn't as great a difference as people think, because the gear spacing of the 4 speed is wider than the first four of the 5 speed. For whatever reason, the 450 is shipped with a lower first gear than the 426 had. When it is re-geared, as I did with mine, so that the 1st gears of both bkes are the same, there is only a 750 rpm difference between the two at 80 mph, and a 4.5 mph difference in top speed, assuming both could reach 11,500 in their top gear. Mine ran right at 90 on pavement with this gearing. All MX bikes have a narrower top to bottom spacing than off-road bikes do, and the 5 speed really isn't that much wider than the 4.

Also run the stock gear ratios on a 426 in your calculations: 14/48. Most I know run a 14/50-52 on there. Compare apples to apples. I dont know of anyone running a 46 on the rear for more top speed.

I used the stock 14/48 for all the posted ratios on the 426. The 450 also comes with 14/48, but I run 15/49 to bring my low gear up to the same ratio as the 426 1st gear. With identical low gears, my 4th gear of 9.67 is 95% as tall as the 426's 9.20 5th gear.

You are correct that the four speed is a cause of the YZ450s poor sales performance vs. the CRF, but that is the result of an incorrect assumption by the public that it will be one gear slower because it has one less gear. It isn't.

  • SC_Spode

Posted January 30, 2005 - 11:16 AM

#9

I currently am running a YZ250f '05 for woods, Enduro's, Harescrambles and really like the bike. I am considering a YZ450 next. Can someone give me a comparisson between the two. Will the 450 be a monster in the woods or can I lug it like a tractor. My best ridding bud runs a KTM 450EXC and could not be happier. I need to ride his to compare with my YZ but its been over a year since I rode his. Anyway, I'm not interested in a KTM 450, I'm interested in a YZ450. What do you guys think? Can you tell me some differences that I might encounter, good or bad. I am concerned that the 4 speed gear box may be to limiting.
__________________

I have an 03 YZ450 that I ride in Southeastern woods.

I used to stall it all the time; very frustrating. Sooo, I did the following:

FWW
Magura clutch
Tune the jetting (mostly fuel screw)

This was better, but not completely what I was looking for. So, I installed a Z-Start.

Magic!

I haven't been able to get out on trails I normally ride to see exactly how it compares, but the reason I put one in it was because I also have an 03 CRF450 and the Z-Start turned it into a good woods bike.

The auto is the key to low-speed, technical riding on the big MX'ers for people with less than AA riding abilities. It's like riding a Honda Hobbit with an F16 engine bolted in!

We don't have enough open area for the top speed to be of concern.

:cry:

  • mnmbb01

Posted January 30, 2005 - 12:50 PM

#10

SC Spode , where in SC do you live, I'm in Greenwood SC.

  • SC_Spode

Posted January 30, 2005 - 12:55 PM

#11

SC Spode , where in SC do you live, I'm in Greenwood SC.

Cool! Just a stone's throw from Parson's and Cedar Springs. :cry:

I'm in Columbia.

:cry:

  • mnmbb01

Posted January 30, 2005 - 01:04 PM

#12

Yeah, thats some of my home turf. Let me know if you come up and ride some time. Where do you guys ride in Columbia, I have a friend that lives there that has a bike but does not ride much because he doesnt have anywhere to go?

  • SC_Spode

Posted January 30, 2005 - 01:13 PM

#13

Yeah, thats some of my home turf. Let me know if you come up and ride some time. Where do you guys ride in Columbia, I have a friend that lives there that has a bike but does not ride much because he doesnt have anywhere to go?

Well, Keith Barnes (Ranger at Parson's and Cedar) mentioned doing some more trail work soon. If that happens, he usually lets us "survey" :cry: the trail afterwards, even though it is officially closed.
You can find out what's going on with the trail maintenance by going to SCORE's website (http://www.truespode.net/score/) and signing up for the email list. I post info pertaining to any upcoming workdays on that list.

As far as riding in Columbia goes... good luck. We usually have to drive a minimum of an hour to ride. :cry:
Tell your friend to get on that email list also, and he can hook up with some of the guys around here.

:cry:





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