Powder power

[stomper]

I’m loving my new 2017 BTX I just purchased brand new. Couldn’t be happier with it on the trails. Has great pull coming out of the corners and on the straight stretches. Top end speed is not great but for the riding I do it is plenty, but I wish it had a bit more mid range to go better in the deep powder. It has the 1.75 backcountry which is great for the trails and still does decent in the powder. What can I do to this sled to give it a bit more get up and go in the powder. Clutching maybe? Something to help the mid range lug in the deep snow. Turbo will not happen so please don’t mention it.

 

[cannondale27]

Can and Airbox.

 

[blueironranger]

What RPMs are you currently running? These motors love to run right at 9000 on the trails which drops back to about 8700 in the powder. If your running under 8700rpm your starting to give up a decent chunk of power. I’m running the Big Venom kit and it really woke up the mid range and allows smoother engagement to help avoid trenching off trail.

 

[stomper]

I just reached the 500km mark on to odometer so I haven’t had it WOT yet but I tried it today in the powder and all I could get was 8350ish rpm at WOT. I didn’t hold it that long but it stopped climbing.

 

[cannondale27]

I just reached the 500km mark on to odometer so I haven’t had it WOT yet but I tried it today in the powder and all I could get was 8350ish rpm at WOT. I didn’t hold it that long but it stopped climbing.

Yea that will make a boring sled. I would shoot for 8800 in deep powder so you have some room for higher when in faster conditions.

 

[stomper]

So the big venom kit will do this for me or is there something I can do to the stock setup

 

[cannondale27]

So the big venom kit will do this for me or is there something I can do to the stock setup

It can be done with either but a lot easier with a clutch kit like big venom since its way easier to add and remove weight. In your case the stock weights are too heavy. You either need to remove wieght or add power. A can and airbox mod would put you right where you need to be. If you choose stock route the rivets int the weights need to be removed and replaced with lighter. Used to do it all the time but it's very time consuming and it's always a educated guessing game so may have to do it a few times to get it right.

 

[Jim D]

I have my airbox opened up with an SLP muffler, and have a PCV and ignition module, set to raise my limiter to 9800. I have a stock clutch set up, but have removed the tip rivet to achieve more shift out rpm once up and out of the hole.

This works great for my set up; it has a 9200 shift out. For you, without the mods I have, you might be perfect, shifting out in the 8800-9000 point.

 

[PeeWee86]

So the big venom kit will do this for me or is there something I can do to the stock setup

If you want your clutch setup to work well in the deep snow as well as on the trail you will need a a helix that will backshift better than the stock straight 43 degrees. All of Yamaha‘s deep snow snowmobiles have helix angles shallower than 43°. Before you spend money on a clutch kit replace your helix with a 42/38 multi angle. I would start with a 3/3 or a 6/1 spring wrap. This will bring up your WOT rpm and have less variation in rpm between on trail and off trail. I am not sure of Canadian prices but in the United States this could be done for less than $100.

The multi angle will reduce the tendency of an initial over rev. I have tried helixes with 8° difference between the two angles and felt that it was too much on my Viper. It was very difficult to achieve a straight shift curve. I think about 3 or 4° of spread is ideal. If you decide to go with a clutch kit in the future the new helix will enhance its performance.