Nytro Gearing

[philsummers21]

Ok whats the verdict on gearing a Naturally Aspirated Nytro with a 156.
18 19 or 20. Heard alot of people going to a 19 with a 162 and some want to try an 18.

 

[Nikolai]

Ok whats the verdict on gearing a Naturally Aspirated Nytro with a 156.
18 19 or 20. Heard alot of people going to a 19 with a 162 and some want to try an 18.

I don't feel comfortable running an 18-tooth gear(too small IMO) so I'm running 19/40. I think it's perfect for the 144-150 track lengths. If I had a 156+ I'd get a bigger bottom gear and go lower still.

 

[philsummers21]

so like an 18/41 ?

 

[fonzi]

gearing

A 40th is the biggest gear available from Yamaha. My choice would be 19/40 with a 162.

 

[SNAFU]

I run 19/40 with a camo extreme 156 and it works pretty well. It seems to hold the track speed and RPM when climbing a bit better than the 20 th. I think going to a 18 tooth sprocket would be too tight of a radius IMO. If I remember right, a shorter chain might also be required for the 18/40 combination.

 

[Nikolai]

I thought Ulmer sold larger bottom gears?

 

[TBird]

Yes he does, a 42 tooth, beware of using it with reverse tho, i have a friend destroying reverse gear and chain using a 42 tooth.

 

[ruffryder]

Yes he does, a 42 tooth, beware of using it with reverse tho, i have a friend destroying reverse gear and chain using a 42 tooth.

any more info? I am running 18/42 gearing....

tick tick tick? lol

 

[WFO or go home]

I am guessing he didn't modify the counter rotation gear (I think that's what it is called) properly.

 

[TBird]

I am guessing he didn't modify the counter rotation gear (I think that's what it is called) properly.

Most problably, but how to know when it's done properly?
He thought it was properly done because a Yamaha mecanic had done it for him, he had left it to "a professional" to mod it, but he might have grinded it to little?
The reverse gear was absolutely shot, and residense from the gear destroyed the chain also.

 

[ruffryder]

Most problably, but how to know when it's done properly?
He thought it was properly done because a Yamaha mecanic had done it for him, he had left it to "a professional" to mod it, but he might have grinded it to little?
The reverse gear was absolutely shot, and residense from the gear destroyed the chain also.

I took mine to a machinist, but I gave him the wrong dimensions.. or maybe I didn't understand Allen's measurement..

I ended up holding on to the shaft and putting the gear on it, then putting it on a bench grinder.. not the best method by a long shot, but it worked and came out pretty even. I then took a file and cleaned the edges up..

The gear is ground down enough when no matter how much you wiggle the gear and shaft, it will not hit the bottom gear. It took me several times of installing everything and verifying, before I got it correct.

 

[motojunkie101]

I run 19/40 with a 162 powerclaw and it pulled it just fine.