Gearing recommendations needed for Nytro RTX

[Dimebag]

Hi.

What kind of gearing should i run on my stretched 144" 1.75" Nytro RTX?

What is the stock gearing? 23/42?

Where is the cheapest place to buy new sprockets/gears?

If i change the upper sprocket to a 19/20 tooth, do i have to change the chain also?

The sled has 4500 KMs on it.

Thanks.

 

[shadow44]

pretty sure stock gearing on all Nytros is 21/39

 

[Turk]

Drop 1 tooth on top & stock chain works fine.

 

[Alatalo]

Stock gearing is 21/39 and the stock chain is a 68 link chain. This means a final ratio of 1.86:1.

If you are going to use a 144"x1.75" track also off trail, I would recommend a final ratio of 2.00:1 or higher. Dropping one tooth on the upper gear to get 20/39 will take you close, but I would prefer 19/39 or 20/40 with that kind of track. All of these gearing combos can be used with the stock 68 link chain, even if the 19/39 will put a lot of excessive chain around the chain adjuster, thus requiring quite a "turned in" chain adjuster. Changing only the upper gear is budget, changing the lower gear is...well, let us just call it slightly more expensive...

I have been using a 136"x1.75" with 20/40 gearing all winter. I can not see how I would get away with a lower final ratio than that.

See pictures below for part numbers and recommended chain. I am pretty sure you can get them from Port Yamaha, at a decent price too...

 

[Dimebag]

What is the stock gearing on the MTX?

 

[rlcofmn]

What is the stock gearing on the MTX?

High Alt sleds are 20-40

 

[Egon]

I use 19/39 on my -08 RTX (121") and the top speed is around 150 km/h.
Since I mostly ride off trail it works great,

 

[Dimebag]

Then I'll go with 19/39

Do I have to change anything on the clutches to make it work good with the new gearing?

Thanks.

 

[Egon]

Dont think so, my clutching seams to work better with the new gearing