YZ400F vs YZ450 top speed

[Altathumper]

I found a good deal on a new 03 YZ450, and have just sold my old 99 YZ400F. What's the speed difference between the two? The top end on my 400 was good, and i'm a little worried that the 450 won't have it on top because it's a 4 spd. I don't ride on the track at all, mainly in the mountains and woods with lots of fireroads. I know I should get a WR450, but they are $2000 more than this one. I have searched the forums and have not found anything as far as top speeds. I know I can always gear it taller, but like I said, I do a lot of woods riding, and don't want to fry the clutch due to slipping it all the time. Any ideas?

[John_Lorenz]

Lot of people like the YZF450 in the woods, allot Less people dislike the YZF450 in the woods.

Speed is not an issue IMO its the 4 speed. some of the 450 owners have have opted to a larger flywheel and gearing.

I own a 426 and i love it in the woods

[Jeffro426]

In my opinion, if your going to be riding mostly trails/woods/desert, or just about anything other than MX i would not choose the yz 450...The 4 speed is awesome for MX, but leaves much to be desired on trails. It just doesnt offer anywhere near the versatility that the 5 and 6 speeds do...it can be made into a decent trail machine, but for the money, you could do alot better. Theres always a debate about this so my advice to you is find someone with a 450 and try it out and see if it suits you on the trails...some people it may, some it may not, but i know i sure didnt like it except on the MX track.

[Matt96xr6]

No need to look farther than the gearing.

Here is the 450 specs:

4th gear (top gear): 21/20 (1.050)

Secondary Reduction Ratio 48/14 (3.429)

426 (only specs I have close):

4th 1.050

5th 0.840

Secondary Reduction Ratio 49/14

So with really one tooth diffence on the 426 mean all else equal, it will be a bit slower. But look at 4th gear, they are the same between the bikes! But wait, the 426 has a 5th gear. So if you have ridden a 426, then ride flat out in 4th. That is how fast a 450 will be top speed.

Make sense?

[cm67yz]

The 426 is smaller the 450 should bet it..Even if thay have the same gears.. ?

[John_Lorenz]

No need to look farther than the gearing.

Here is the 450 specs:

4th gear (top gear): 21/20 (1.050)

Secondary Reduction Ratio 48/14 (3.429)

426 (only specs I have close):

4th 1.050

5th 0.840

Secondary Reduction Ratio 49/14

So with really one tooth diffence on the 426 mean all else equal, it will be a bit slower. But look at 4th gear, they are the same between the bikes! But wait, the 426 has a 5th gear. So if you have ridden a 426, then ride flat out in 4th. That is how fast a 450 will be top speed.

Make sense?

I dont think thats right, There has been posts on this subject before, the final ratio between the 450 4th and the 426 5th is the same, meaning top speed will be the same. ?

[Jeffro426]

The 426 is smaller the 450 should bet it..Even if thay have the same gears.. ?

Thats a pretty lame statement Size of the motor really has very little to do(at least in this case) with it as both of the motors put out almost identical HP numbers...however, the 450 has a slightly smoother power output. In a flat out drag race, or dash to the first turn, given equal riders it would probably be very close to neck and neck.

[cm67yz]

Sorry there Jeffro426. :awww:the 450 has a slightly smoother power output.What :excuseme:Don't the 450 hit harder ? I think the top speed post has been done to death

[Matt96xr6]

Are we not understanding? If both bikes use the same gearing and have the same RPM limit, 4th gear both bikes would top out the same. The difference here is the 400s 426s and the WR450s have a 5th gear. Technically an overdrive, but another gear which means more speed!

So since the 4th is the same ratio on the 450 and 426, 4th gear pinned everything else the same (tire height, sprockets and rev limit) would result in the same speed. Now shift the 400, 426 or wr450 into 5th gear. It goes even faster top speed and leaves the 4sp YZ450F behind.

now that says nothing about power output or acceleration, just the speed "pinned" in top gear.

[Jeffro426]

Interesting...how many people brag about much smoother power just by putting, get this, a 450 cam in there 426 ? While in my (ex 2stroker) eyes, neither of the bikes have a "hit", but the 450 is definetly smoother than the 426 is.

[KillerHiller]

When dialed in, the 4 speed is not an issue. I run a 14/50, which is 2 teeth bigger then stock in the rear. Works great in the tight stuff without abusing the clutch, and still has more top speed then my 01 YZ250 2 stroke. Even a 14/51 is still fast, and better for really, really technical stuff. The suspension is stock, but dialed in, 10 oz flywheel, CRD exhaust(96Decible), softer springs for my wt., 168., and some other woods goodies.

I still race MX on it as well. For some reason, the bike gets a bad rap as a woods bike, but with a little minor setup, it's very versitile. No B.S.. It really is a good woods bike.. and really fun! ?

KH

[Altathumper]

Thanks for all the posts, it's a real debatable subject. The brochure right from Yamaha has the 03 YZ450 listed as having a 4 spd tranny, yet gives 5 ratios!!! gonna give it some more thought... ?

[SC_Spode]

I'll 2nd Jeffro and KH:

My 450F has a more linear power delivery than my 98 YZF did.

And my 450 is close to KH's in set-up. I put lighter springs in it and am in the process of fiddling with the suspension. I REALLY like it so far off-road! And this is the southeast, not Baja!

It's much more nimble and easier to ride than the 99 WR4F I recently sold. Doesn't have the granny gear, but I giggle every time I ride it!

Shhhh, let's keep it our little secret! ?

[gmtech16450yz (motobark)]

You guys are missing one vital piece of the gearing calculations- the primary reduction. The primary reduction of the 450 is 2.818 and the 426 is 2.952. If you do the math, (if I remember right) the 450 is actually a little TALLER geared than the 426. So all things being equal, with both bikes at the same engine rpm, (and both bikes in their TOP gear) the 450 will have a slightly faster rear wheel speed.

As for the 4 speed vs 5, after owning both my opinion is it's not that big of a deal. The difference between the WR trans and either YZ trans is a way bigger difference. Especially first gear on the WR, now that's a granny low!

John

[motomike137]

It's not how many gears it has but what the spread between them is that counts as long as you have a motor with a wide healthy powerband. All of the MX bikes have close ratio trannies and the difference in the overall spread between the 4 and 5 speeds is negligable. I've owned all 3 flavors of the big YZF and the 450 is easily better and more fun than the other two in all conditions. It is just as versatile as either of those bikes and the CRF for that matter. The CRF could easily have a four speed in it also. If you truly want to go from crawlin to warp speed without changing sprockets you need a wide ratio tranny. ?

[Hick]

The CRF could easily have a four speed in it also.

But it doesn't.

?

[Fastest1]

Matt, The 4th gears are not the same. The 4th on the 450 is the same as 5th on the 426. Big difference. Top speed is about the same with stock gearing. I did the calculations awhile back, the top speed was either 78-82 mph. Enough?

[motomike137]

Hick, what's your point? ?

[sirthumpalot]

Hick, what's your point?

I think he's happy that the CRF doesn't have a 4 speed. ?

[motomike137]

Why would that make him happy ?