09 xp track speed

[rmk680]

anybody gearing down to get better track speed not enough hp or should be looking at clutching

[skibeadoo]

IMO you need to do both. I have geared down both my sleds and clutched many times. I still hold 45-47mph around Revy riding. Stock other than can, gears and clutched many times over.

[blastoff]

on the 08 XP last year in Mcbride the speed was same as above posted [46-48], stock unit, the Yamaha nytro was only 38, RMK 700 was the same as the Nytro

[Dynamo^Joe]

If you start to gear down say from your 21 to a 19 you'll start to probably find a black ring apparent in the primary.

What is happening is with the lower gear ratio, under full throttle the belt will be lower in the secondary. The roller in the secondary will be at a larger helix angle (reverse 43/47) so then there will be even less belt clamp than a lower helix angle.

From experiences the rpms will recover quickly yet may fluctuate but the belt will slip in the secondary - the primary will start to have a buildup of black ring(s).

[drop the hammer]

IMHO, put in a clutch kit, get it dailed for your riding area and hold on. I haven't seen a need to adjust gearing on Summit XP's, once you address the clutching and sled setup.

I haven't seen an increase or decrease in performance on the guys that did it. But it did require a slight less pin weight or maybe half a clicker adjustment up (not possible) but this is what it did for them. A lot of guys regeared the 154's... but remember the CVT adjusts to the gearing so you're not changing the gear ratio to motor, just changing where the rollers sit on the ramps as well as where the belt sits on the clutches at WOT (gear down = pin weights go further out from center and primary is a bit more closed).

I guess what i'm saying is put the money into a clutch kit for now, get it dialed and see what it does, you may just be happy with it like that.
here's an animation of tra guts moving:
TRA system

[drop the hammer]

Also watch increasing dog leg on chain, robs efficiency, when going smaller top gear. Also small radius gear is not as efficient as larger gear. So really a re-gear should be done on bottom gear and include new chain to ensure minimal dog leg....but now your talking more money.

By the way i'm pulling 82 km/hr track speed at WOT, no run at hill, 3 feet plus snow in Revy. I can get higher speeds than that by taking a big run at it or up an existing track....but that's polaris poaching style

[summitized]

how much for a kit 09 xp 154 gearing 19/45