gearing, clutching help wanted asap please.

[smalltownpower]

i posted a week ago, or i thought i did, but i cant even find my old thread. what are you guys seeing for top speed across fields. its a 2011 nytro rtx with stock gearing, stock clutching and 121x15x1.75 track, and across a stubble field with moderate snow were seeing a top speed of 105kmh at 8850 rpm. the engines got tonnes of power to pull it faster, it just wont upshft. i think its somthing in the secondary. should we be adding weight to the primary to pull harder or what, i dont know. help

2011 rtx 121x1.75x15
power comander 5 with a good tune on it
3 2 inch air box pods
mbrp slip on exhaust
stock clutching and gearing

central saskatchewan 1500 elevation
150 pound rider with suit and back pack.
agressive rider, 75% off trail
wants to go fast!!

thanks in advance

 

[mike3577]

I wonder what it would do without the power comander?8850 rpm is a little low I think,is'nt perfect like 8950 maybe take alittle out of the tip,thats alot of track to spin also.sorry not much help but to get your rpms up take out weight

 

[mike3577]

I wonder what it would do without the power comander?8850 rpm is a little low I think,is'nt perfect like 8950 maybe take alittle out of the tip,thats alot of track to spin also.sorry not much help but to get your rpms up take out weight

 

[smalltownpower]

Also another thing to note, the belt is about 3/4 up the primary sheive, so it is not fully shifting out unlike our phazer and 4 vectors.

 

[Dano]

1.75 track is a huge track if your looking for top speed. I would check the temps of your clutches after a good pull in the snow. If their running really hot, your probably having belt slip. If clutches are warm I would try and loosen the secondary spring a tad if RPMs stay high.

Dan

 

[smalltownpower]

I know 1.75 is alot for top speed, but my brother is 130 pounds, 5 foot 5, the sled is basically driving itself haha, there's no reason it shouldn't pull more then 100kmh off trail if the Rpm's are there, and engine is under no load at all, it's just screaming freely, the clutches just aren't pulling, the primary is only shifting out 3/4 of the way, even on groomed trail.

 

[gc_srt]

Normally I would say you need lighter weights because of your mods but you are pretty close on the target rpm. How is it shifting from 0-100kph? Does it hold 8850 from 30-100kph? You are clearly not shifting into overdrive. Is anything worn out? Does your primary move freely without the belt and can the secondary helix spring be fully pushed in?

 

[gc_srt]

Check this article out:

http://www.gates.com/brochure.cfm?broch ... on_id=3850

 

[smalltownpower]

What are you guys seeing for top speed across a stubble field with about 1 foot of soft snow and a really firm base? Everyone I talk to at the dealership said it should pull more but don't help any with clutching it

 

[sorenson1610]

Are you trying to top out in those conditions or just wondering whats normal? With a foot of snow your not going to get very good top speeds but i think you know that right? So 60 mph is your max.........you should be more then that even with the bigger lug track. Weird, what belt are you using?

As far as rpms, might want to get a adjustable clutch kit. But your rpms are pretty close to ideal so who knows. Who tuned your pc5?

 

[Race_blue60]

ditch the 1.75 track and MBRP, can sounds bada$$ but doesnt make any HP we proved it on the dyno and the 1.75 acts like a big sail when coming around.. if you do most of your riding off trail why worry about top speed? cant really have best of both worlds with a deep lug track

 

[natedawgedog]

105kph is only about 65mph that is way slow. you said you are getting the belt to only go up 3/4 of the primary, how far is it getting down in your secondary? sounds like you are needing to do some clutch work done. when you bought the sled did it come with the factory clutching or clutching set up from your dealer to the correct altitude that you ride in? I think your sled is clutched for higher altitudes than what you ride in, causing your clutching, gearing, and track to work harder in the denser air.

 

[natedawgedog]

I should also add that I have an xtx with the 144/ 1.75 backcountry track and I see speeds around 100mph in almost all trail conditions on top end and about 75-85 when ripping off trail in a little bit of powder, track speeds on deeper snow days are also pretty high but never pay attention to the nytro gauge when Im playing in better snow anyway.

 

[billymx815]

These are not top-speed sleds but you should be getting atleast somewhere between 90-100mph with that set-up. Most likely closer to the 90mph then the 100mph but 65mph is not right. I'd start with clutch & belt because your RPM's are close so something is slipping and or not engauging properly.

 

[smalltownpower]

Thanks guys, I know for a fact that there is somthing wrong, because our phazer MTX can do 100 across the field, it struggles, but it can, and all our vectors with 1.25 and 1.5 inch ripsaws can easily do that speed. I also believe that your MTX's may have better top speed because of a different approach angle. Even with stock skis we are not having a problem with it falling down, after about 40km/h it is up Ontop of the snow and cruising, unlike the vectors which will trench until about 80 kmh. Today I will take the springs out of both clutches and see if they both open and close smoothly, I'll also draw some lines on them with a marker to check a belt height. There is currently no shims in the clutch for belt height, and the belt is barely above the shelves, just enough to catch your finger nail on, so belt height or correct.