14.5 rollers....YPY or OPO spring ??

[terez]

Going to add 14.5 rollers to my stock Nytro FX.
Which spring to complement the engagement and midrange improvements but reatin my finsih rpm to around 8900~9000.

I know the peak hp is a lil lower but I like the overrev for top end and while the 1050 doesn't make any more power revin' it out it doesn't fall on its face either and the rpm will translate into mph on the hardpack.

I may try a straight 47 and or 43/47 later as well and that will prolly drag the finish rpm down a couple hundred rpm too I assume?

YPY , OPO or ??

 

[radianguy]

Before my mods I ran the YPY, ulmers clutch kit comes with OPO. I was pleased with the 14.5 rollers and YPY over stock set up.

 

[nitris223]

I have the OPO in a MTX set up for flatland riding and Hindle full exhaust.

 

[newfie09xtx]

Ypy works good. I am very impressed with mine. Can't speak for opo.

 

[baggs66]

set-up my sisters 09 with ypy which lowers engagement and smooths it out along with 14.5 rollers , 45/39 helix and removed the rivets in the tip of weights to bring rpm back up runs great. not sure if same setup on 13. i have been running the ppp lately which lowers the engagament but will be more rate to keep rpm's for ya.

 

[Stone9]

I went GPG to keep r's up. only time it revs over 9150 is on a long stretch of open water

 

[nitris223]

OPO I think comes in at 2900 - 3000 rpm engagement . Somewhere in there. Nice and smooth, easy loading onto a trailer. Never tried stock spring with the 14.5 roller.

 

[Nytro Nasty]

So are the color codes orange pink orange or yellow pink yellow? I heard 14.5 rollers from srx, and same with 47 degree helix with stock weights and ypy. Anyone tried that yet? Who has spring rate charts they can post? What is ideal top rmp before sweet spot or powerband drops off. Heard should be lowered like 400-800 rpm over stock? Lots of variables with clutching so is tough. Running 136 with 1.5 paddle. Currently stock gears and clutching. That won't last long.

 

[nitris223]

Go up to the top of the page in the dark blue border there is a section called TY Tech. Click that and then click Snowmobile tech and then click clutches and gearing I think. There will be spring charts, weight charts , rollers etc. Lots of info to read in there.

 

[Nytro Nasty]

I have had my dealings with 2 stroke clutching over the years but this 4 stroke a different breed!

 

[Marc Augustine]

Can anyone tell me where to get 14.5 rollers for the nytro??

 

[Hooray!]

Can anyone tell me where to get 14.5 rollers for the nytro??

SB has a kit (what I bought w a spring), but I think you can source them alone as well.

 

[Marc Augustine]

I've got a YPY spring and the quiet kit, was looking for the rollers, Yamaha parts houses have 14.5 rollers for about $150 and I see Schmidt Bros. say there's are 14.7 for $80 something, wonder how much the .2 of a mm would make. This is all new to me so if these sound like dumb questions that's why. If you have the SB set up I take it you have the 14.7mm rollers, what did you end up with for engagement rpm's, not sure what the specs are on his spring.

 

[Hooray!]

I've got a YPY spring and the quiet kit, was looking for the rollers, Yamaha parts houses have 14.5 rollers for about $150 and I see Schmidt Bros. say there's are 14.7 for $80 something, wonder how much the .2 of a mm would make. This is all new to me so if these sound like dumb questions that's why. If you have the SB set up I take it you have the 14.7mm rollers, what did you end up with for engagement rpm's, not sure what the specs are on his spring.

I think the 14.7's are not as easy to source as 14.5's. If you talk to Chris, 14.7 was the ideal size after all his testing, larger and smaller with different springs. The tach jumps up quickly but it engages between 2750-2850rpm, below 3000, which is perfect for what I wanted, nice and smooth takeaways without any compromise on top end (I get 8900rpm and just into triple digits on top). Very happy with all the SB kits I have purchased (and all items in my signature), as others have noted, you can source all the individual parts if you have the time and energy or buy them from companies like SB, or BOP, Rocz, MountainTech and others... they all support our Nytros and put the time in to test and kit things up, easy to buy and I like the idea of supporting their continued efforts to keep our Nytro's on top of their game.

 

[Marc Augustine]

I'm all for supporting these guys, there would be alot of trial and error without them, and it's nice to deal with people who go out of there way to get you going. I just put Rocz yamaheaters on last week and wow those are great, I will be getting his HIDs setup. I picked this Nytro up last summer, skid rails and drivers were trashed, I put this 13 AC float skid under it and really like how it works, never rode the nytro with the stock stuff so nothing to compare it to. My first Yamaha and 4 stroke, wish I would have went this way when I was younger, got a 2 page list of things I want to do so this one will be with me awhile. Thanks for the info Hooray, I will be getting the 14.7's from SB and if this YPY spring doesn't get me numbers like yours I'll get there's.