MTX Nytro Clutching

HPCrazy · Nov 14, 2009

There has been plenty of time for tuners to find the perfect clutching for the stock Nytro. I was wondering if anyone would be so kind as to share!
I would like to hold 9000 rpms when climbing is this possible? Right now I am at 83-87 depending on snow conditions. I have tried adjusting the stock secondary spring with only worse results. Has anyone tried the white secondary spring? The OEM is a softer pink.

irondave86 · Nov 14, 2009

9000 is a bit high, give us some more details. Any mods? elevation? track length and size. that kind of stuff.

HPCrazy · Nov 14, 2009

156/16/2.5 camo ex, slipon muffler, 6500-10000 feet. Setup spring snow it will hold 88-90, but anything deep brings down rpms. I was thinking a little stronger spring will hold higher rpms under greater load. According to the manual specs I can't get a stronger primary without messing up the engagement(assuming engagement is preload).

philsummers21 · Nov 15, 2009

GWG in the Primary and Arctic cat yellow in the secondary. Stock weights and helix. Works pretty well. Thats with a 162x15 went to a 18/40 gearing this year we will see.

mtncat · Nov 15, 2009

Nytro clutching

IMO the problem you have in the soft deep snow is caused by the recycled snow making its way up to the front of the tunnel, the clearance with a
16x2.5 in the nytro is very tight, the snow that is being pulled up the
track to the front of the tunnel can not evacuate fast enough causing the loss of RPM. This is why you dont see the RPM drop in settup snow.
I fought this problem on a 08 nytro, snow conditions constantly changing made it tough to hold RPM. the boosted sleds can handle the 2.5 with ease
where the stockers seem to fight the RPM loss with the 2.5

TBird · Nov 15, 2009

I agree with mtncat, there's alot of snow following track around.
So there's a couple of things guys do, cut down the track a bit to get more clearence.
Definitivly an harder spring, many have success with oem white @ 3-3 or 3-4 or an AC yellow 1-0.

HPCrazy · Nov 15, 2009

Snow clearance, possibly but not likely with fluffy snow and over 2 1/2 inches. Cutting the tips of the track will do nothing IMO. Clutching will definitely fix the climbing rpms its just finding the right combo. Considering the almost infinite number of combinations possible (weights riveted weights, helix dual angel helix, prim spring, sec spring) there is more than one combination that will dramatically increase the performance of any machine!!!!! The only problem is you need a warehouse full of parts and a rocket science knowledge of clutching!!

I ordered the white spring I will post results. If no luck I will try the other combo suggested.

I think this is the most important info that should be shared between sledders to bring the level of performance to its highest for all machines. And if YOU have the right clutching combo YOUR THE MAN!!!!!!!!!!!!!!

THANKS :beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer;:beer; where was I

philsummers21 · Nov 15, 2009

Agree with HPCrazy. Clutching is most important in my book. Can have all the hp in the world but if it isnt getting to the ground who cares.

HPCrazy · Dec 1, 2009

PHIL21
How is the 18-40 gearing working out for you? I was thinking of the 18 as well. With the 20 gear my belt is not even climbing half the primary and heating up, rpms @8300 stock spring in tightest hole(climbing in powder)

On the trail its @ 9220 rpms and 140kms +

Hard to wrap your head around the complication of clutching. Could it be the weights? There are different ramps and riveted weights.

Nikolai · Dec 2, 2009

I went out one day last year with the cat yellow, red/white, and stock Yami pink. All I did was play with every secondary position possible and ended up with the stock pink at 100*. A stiffer primary (GWG like mentioned above) will hold RPM's better. There's an even stiffer one but it has less preload and I didn't like it. It'd be nice to find a spring with more rate than the GWG but the same preload.

No rocket science in clutching. Go out with clean clutches and all your clutch parts and just play on the hill for a day. RPM's, track speed, and belt wear will tell you if it's an improvement or not.

philsummers21 · Dec 2, 2009

haven't had a good test on the 18 yet. just put it on for this year. the new 162s come with a 18 top so im pretty sure is the right direction

HPCrazy · Dec 2, 2009

Not as much interest in this thread as I had hoped, but I found the mother of clutching articles. http://www.snowtechmagazine.com/articles/2001/clutch/cltchtun.php
Check it out

resent:

Nikolai · Dec 2, 2009

There's been a lot more clutching talk over on TY in the MTX forum. Might try searching over there. Most of the guys on SW have turbos so stock clutching isn't very interesting to them.

ruffryder · Dec 2, 2009

I used stock weights, no rivets, stock primary spring, stock helix, with yellow arctic cat secondary spring last year and it worked very well.

I changed to super tips, and the aggressive nature of the weights was not a match for the secondary helix angle. I tried using 14.5 mm rollers and that didn't work either, as it made the back shift horrible in heavy wet deep spring snow.

I am going back to the stock rollers with the supertips, and will be using a helix that ulmer recommended. I haven't ridden it yet though.

The stock weights are super fat and heavy, but yet the profile of the weight makes it act like a much lighter mass weight.

TApeX_07 · Dec 2, 2009

What degree did they recommend?

ruffryder · Dec 3, 2009

TApeX_07 said:
What degree did they recommend?

I am not sure how much I can tell... you know.. his setup and all. It is a progressive helix, with a higher starting angle and a lower finishing angle, as compared to the stock 08 MTX.

Keep in mind though, that this is for the supertip weights. They are more aggressive then the stock weights, and therefore will require a lower helix angle to get back your backshift.

I sometimes forget that it is not the actual values of the helix that gets you backshift / upshift performance, but rather the ratio between upshift on the primary vs. backshift on the secondary.

D4ngerruss · Oct 15, 2012

ok so I saw your videos on youtube. Boondocking with the turbo sled does ok?? I guess I'm used to Cooke CIty or some deeper, steeper areas in that country. Swerving around trees at a steep incline or trying to sidehill up a sidehill were its crucial to manuver the sled it does ok? I am sure it'll take getting used to but want to be ahead of the curve learning how to run the thing. Never driven a push turbo sled. I am wondering about clutching too? If the dealer changes it with the install of the warranty turbo.

constech · Oct 15, 2012

The snow build up using 2.5 inch track is definatly more of an issue than you think. Nytros are tight up there MPI actually puts a challenger extreme 2.5 track, but they trim it down to 2.25 even on their turboed and supercharged sleds because they lose track speed with the snow build up.

Blueboy1 · Nov 17, 2012

philsummers21 said:
GWG in the Primary and Arctic cat yellow in the secondary. Stock weights and helix. Works pretty well. Thats with a 162x15 went to a 18/40 gearing this year we will see.

Does anyone know part numbers for the arctic yellow spring. The GWG primary, is that a yamaha spring for the primary?

..SNAKEBIT.. · Feb 18, 2013

QUOTE The snow build up using 2.5 inch track is definatly more of an issue than you think. Nytros are tight up there MPI actually puts a challenger extreme 2.5 track, but they trim it down to 2.25 even on their turboed and supercharged sleds because they lose track speed with the snow build up.

would it help to port the track as far as snow in the front of the tunnel?

also on the yellow cat the spring end dont match the Yamaha spring is that why the 1-0 setting??

MTX Nytro Clutching

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