High Gearing Viper XTX LE

[Schlorven_]

I hav a viper xtx le 2,25 lugg track, according to gearing spec the machine have 21/41.

AC XF 7000 HC have 21/49, and i have a freind who have a 2013 AC 800 HC, and he has the same gearing that XF 7000.

the 21/41 gearing is for 116 mph, and 21/49 is for 97 mph

inputs on that? could this be somthing to have in mind, according to rpm drops in powder.

Fastes i have seen is 82 mhp, but i know i shouldn drive that fast whit that typ of track

 

[cannondale27]

Here:
Might as well join this. Definitely gearing is a factor. Guys are testing right now.
http://www.ty4stroke.com/threads/gear-swap-on-le-model.133579/page-3

 

[Srxspec]

Your XTX LE model with the 2.25" track has 21/49 gearing in it (if it uses the same specs as the USA models). The Yamaha information is incorrect.

 

[Schlorven_]

i see, so the onley thing to do is to open the chaincase and check then.
but they said it was 21/41

 

[TD Max]

i see, so the onley thing to do is to open the chaincase and check then.
but they said it was 21/41

You can do this without opening the case.

Mark one track drive cog noting the clock position.

Mark secondary at a specific clock position

Rotate secondary 7 turns

Check clock position of the marked drive lug

The Drive lug should be in the same clock position and have rotated 3 times.

3 x 2.33= 6.99

7/2.33= 3

You could do less revolutions, but the math works out so good with the 2.33 ratio.

 

[stingray719]

Your XTX LE model with the 2.25" track has 21/49 gearing in it (if it uses the same specs as the USA models). The Yamaha information is incorrect.

Is that also a 7 tooth track driver like the MTX in that?

 

[Srxspec]

Is that also a 7 tooth track driver like the MTX in that?

8 tooth

 

[Schlorven_]

You can do this without opening the case.

Mark one track drive cog noting the clock position.

Mark secondary at a specific clock position

Rotate secondary 7 turns

Check clock position of the marked drive lug

The Drive lug should be in the same clock position and have rotated 3 times.

3 x 2.33= 6.99

7/2.33= 3

You could do less revolutions, but the math works out so good with the 2.33 ratio.

TANX!! i will check tomorow =)

So if it´s 1,95 i gear (21/41) it would be 5,85 turns on the secundary (3x1,95=5,85)

 

[TD Max]

There are other ways to check this, but with 3 revolutions landing so near a whole number (6.99) clocking at the same place was just so simple. I did not have to watch the drive sprocket while turning the secondary.

You could run the drive sprocket 1 full revolution counting the revolutions of the secondary instead and it should be nearly 2 full revolutions for 1.95 ratio. Since we know that there are only a few possibilities it's close enough, but if you are not sure the options it's often better to run several revolutions to spread the results and reduce the error. In other words you could do 19.5 revolutions of the secondary to get 10 complete revolutions of the drive axle or 39 revolutions to get 20 complete revolutions and be certain that it is not 1.90 ratio, or some other odd number.

Landing on or near a whole or half takes out the guesswork