comparing 4 speed to 5 speed

[tdd6405]

i was wandering what the difference is between the tranny of the yz450 4 speed and say the yfz450 quad tranny

the gear ratios of the 4 speed are the same as the yfz's 2-5. is this meaning that its basically the transmition of the yfz without the 1st gear? or is it a combination that makes up the ratios?

[Hick]

the gear ratios of the 4 speed are the same as the yfz's 2-5. is this meaning that its basically the transmition of the yfz without the 1st gear? or is it a combination that makes up the ratios?

I couldn't find any info on the ratios for the quad, but to answer one of your questions yes, a "combination" makes up the final ratio.

I'm sure you understand the affect the final gearing (sprocket combination) will have, but there is also the primary ratio, this is the gear ratio between the crankshaft and main transmission shaft. I wouldn't be surprised if the quad has a different primary ratio (of course it also has a different final ratio also).

The primary ratio on the '03-'04 YZ 450 is 62/22, that is the transmission is slowed down by this factor (22 teeth on the crank drive 62 teeth on the clutch basket). They changed the '05's YZF 450's primary ratio by one tooth, I think it is one tooth taller but I forget...

Hope this helps somewhat. Do a search on this topic as I believe this has been discussed here before (quad tranny vs. the YZ).

[tdd6405]

thanks.. basically, im trying to sell the motor and everybody posted on the site sayings its the exact same tranny as the yfz450 tranny, they jsut left out the first gear. they compared the ratios, i dont know which ratios they were, but they were the same (yfz's 2nd-5th and yz's 1-4th). i dont think its the same tranny, so thats where my question is coming from.

[Hick]

i dont think its the same tranny, so thats where my question is coming from.

I wouldn't think so either, it may share some parts but I would think the quad would need stronger internals to deal w/ all that weight and traction.

?

[yzf450jack]

The yfz has the WR 450 motor in it ?

[tdd6405]

yeah, supposively the yfz tranny gears are beefed up. but im mostly just talking abotu the way its geared i guess. i hate tranny talk.. lol.. so then i'll put it this way:

is the YZ450 tranny the same as the WR450's 2-5th gears?

[yzf450jack]

The wr and yz gear ratios are not the same in any gear I put the wr gear box in my yz i wanted to see what gears were the same there not

[stainlessTT]

I have an 04' YZ450F dirtbike. All I know is sometimes I wish I had one lower gear..... and most of the tome I wish I had one higher gear.

What speed does my bike top out at w/ original sprokets???

[Scooter426]

I heard it was ~75mph

[grayracer513]

My 450 is geared 2 teeth higher than stock. Set up this way, it has a low gear identical to a YZ426, and 4th is a little higher than halfway between the YZ426 4th and 5th. On paper, not accounting for tire slippage and the like, it will just clear 90 mph at 11,500 in 4th, and it will hit the rev limiter in high gear.

A WR gearbox would give you a little lower 1st, alsmost exactly the same 2,3,and 4th, and then a 5th on top of that. In order to switch from 4 to 5, however, the complete transmission has to be changed out ($750)

[RocketScientist]

The YZ and the YFZ 450 transmissions will definitely not interchange. I picked up a 2005 YFZ tranny and attempted to install it into my 2005 YZ. The YFZ shift cam is longer and one side fits a different size bearing. The forks are offset by about 3/32 inch and the fork openings are a different diameter. Also the pins that the forks are attached to are longer. The primary and drive shafts are longer by about ¾ inch. All the gears are different, and I think they are not interchangeable. My guess is that the YFZ case is wider to accommodate the wider transmission and forks. Don’t try what I did. It will not work. I am going to get the WR tranny. If anyone wants to buy a complete YFZ tranny or a 05 YZ 450 tranny with less that 5 hours on it, pm or email me.

[yfzut]

heres the qaud

1st Gear 29/12 (2.416

2nd Gear 27/14 (1.928)

3rd Gear 25/16 (1.562)

4th Gear 23/18 (1.277)

5th Gear 21/20 (1.050)

heres the yz

Gear Ratio - 1st Gear 27/14 (1.929)

Gear Ratio - 2nd Gear 25/16 (1.563)

Gear Ratio - 3rd Gear 23/18 (1.278)

Gear Ratio - 4th Gear 21/20 (1.050)

[grayracer513]

The YZ and the YFZ 450 transmissions will definitely not interchange. ...

Thanks for being the lab rat. I suppose someone had to, but now we know for sure.

So, I wonder whether the '06 YZ450 5 speed will fit.....

[Spadman450]

Ditto on the thoughts from GrayRacer.

I have been wondering about doing the YFZ 5 speed swap to either a YZ or WR. There are a lot of bits and pieces from the YFZ that I have found to be useful on my SuperKart application. I believe the starter motor is HD compared to the WR and might be interchangable (albeit, requiring a crankcase cover swap and some other bits).

I wish there was a way to accumulate a list of what will swap between the 3 motors and what the differences are between the year groups within the motor types. I know several bits of info in this regard, some learned the hard way... as seems to be the case for RocketScientist. Many of these bits of info are out there, but lost in the maze of the various posts.

Anybody, have thoughts about a way to accumulate an ongoing list???

Regards,

Don E

[Hick]

Thanks for being the lab rat. I suppose someone had to, but now we know for sure.

Another ditto here.

You knew it was only a matter of time before somebody here tried this...