400ex transmission gears

[fast2007]

where can u buy different ratios? Which do u suggest changing and to what ratio??Had a friend that changed 3rd gear ,dont no to what or where he got it,but he would pull everyone everytime in 3rd...Any advice??

[Pipeless416]

your friend tells some good stories. you can only change the external gearing.. ie- front and rear sprockets.

[fast2007]

No he didnt...Someone sells them, when I find out I'll let u no where..;)

[jcs003]

Originally posted by Pipeless416
your friend tells some good stories. you can only change the external gearing.. ie- front and rear sprockets.

x2. in 05 they made some internal gearing changes along with the reverse gear, but they were insugnifigant from what i have been told. also, i seriously doubt the transmissions are interchangeable.

[AtvKid4Eva]

yeah just change the front or rear sprockets according to what you are trying to gain (top or low end)..never heard of anyone changing the internal gearing.

[rubbersdown]

x3, no one makes them, you would have to have it custom made.

[Ntensweapon]

Is it possible he used an XR400 gear? Some info I found shows a a taller 3rd gear than the Ex. However some info I found shows a shorter gear in the XR. Perhaps they changed internal gearing throughout the years? I didnt put much research time into it. The primary reduction between the two is the same but individual gears differ. Possible the XR600 gear was used? Not sure if the shaft diameter is the same.
I do agree no aftermarket gear would be possible. Unless it was a very expensive, one off, custom made gear.

[Pipeless416]

i read that the XR and EX third gears are the same. i thought about that as well, so i put a little research into it and came up with that.

[MtnEX]

I'd be interested (for my Kawi) if some place does actually redo trans gearings.

The pros I am sure change this stuff inside to suit them.

They have the mechanics and access to the parts.

I don't know that it is possible to change just one gear in there... maybe, I dunno...

But see that right there is why "we" don't mess with it... lol...

[fast2007]

My buddy at turtle racing engines(Terry pope) said they do not make any ,so that settles that..LOL

[hocman123]

i would be willing to bet he but a stage 2 hc which really opens up the engine in the mid range

[fast2007]

maybe so..I dont know he didnt get infront of me either way ..:D

[1krazyquadridr]

This information is not all correct. The EX and XR400 transmissions are completley interchangeable, and offer different gear ratios throughout the range. I have installed the XR transmission gears in my EX because it offers a better 1st gear ratio for MX racing. The gear ratios are as follows:

EX XR
1st 2.916 2.62
2nd 1.937 1.84
3rd 1.473 1.40
4th 1.181 1.12
5th 1.00 .93

If you don't believe me, go to cheapcycleparts.com and look at the two different transmissions, and calculate the ratios for yourself.