BUMP STEER IMPROVEMENT

[ruffryder]

The problem is the engine can't be any lower and at most without the cooler could be only like a inch back.

instead of moving the engine back, move the skis further forward...cough cough...

and also replace the tank with one that distributes the weight a little better then some of it being above the engine..

 

[rlcofmn]

The problem is the engine can't be any lower and at most without the cooler could be only like a inch back.

instead of moving the engine back, move the skis further forward...cough cough...

and also replace the tank with one that distributes the weight a little better then some of it being above the engine..

Exactly, or move the battery back, or the cooling system to a conventional tunnel system. Or the steel sub frame. But yes I agree with you.

 

[AKrider]

 

[nytrolovin]

zbroz the cure?

As of right now there is a zbroz front end for the nytro on ebay for 725 obo could be the answer?

 

[AKrider]

I've never ridden the Zbros front end but from what other forum members have checked, it doesn't appear to improve anything with bump steer. Zbros allows the rider to adjust the caster angle by shimming the upper a-arm back and forth. I suspect the a-arms are stronger than stock. Here is a hill climb video of a guy using them.

http://www.youtube.com/watch?v=NtuCEKaB ... ideo_title

 

[00-NUKE]

I've never ridden the Zbros front end but from what other forum members have checked, it doesn't appear to improve anything with bump steer. Zbros allows the rider to adjust the caster angle by shimming the upper a-arm back and forth. I suspect the a-arms are stronger than stock. Here is a hill climb video of a guy using them.

http://www.youtube.com/watch?v=NtuCEKaB ... ideo_title

I had a little bit of time today to run some testing with your tab-in theory. I'm getting less bump steer than stock, but now I am receiving a toe in effect. I shortened the tie rod 1-1/8" which is BARE MINIMUM to locate it on the inside of the spindle. I've also tried raising and lowering the monting point after adding the tab. It's looking like the lower tab on the spindle is the SWEET SPOT.
I'm on the fence as to which way to go with this, so I'll keep you all posted.

 

[AKrider]

 

[00-NUKE]

I glad to see you were able to replicate my results. The Phazer tie rod end I was using was much thinner than the stock one. But, the inside diameter of the Phazer spindle was larger than stock. I happened to have a bushing that allow me to mount it with a different bolt but I still had some play and I realized I could not get accurate enough readings. That caused me to just go and grind the collars off my stock tie rod end. I'd hate to ruin a perfectly good '09 spindle just to find out the tab isn't the sweet spot. Maybe just grind the ball on stock tie rod end down pretty close to flat? Of course then is won't be able to articulate enough through the stroke.

I've got some Rev spindles coming in that I bought cheap off eBay just for testing. They use a single tab so assuming they bolt up the to Yamaha ball joints, I'll have a lot more flexibility in shimming the tie rod up and down. But they will probably throw in a completely different set of variables.

Rlcofmn wanted to try flipping the inner tie rod mount over to the other side of the arm pivot assembly (#17).
http://www.ronniesmailorder.com/fiche_s ... detail.asp

Now that I'm looking at that part, I think I see another issue. The pivot assembly swings back and forth and changes the elevation of the inner tie rod as you turn the bars. I don't see this being good thing. But, we've not been testing things with the bars turning, just the straight ahead bump steer. Still, (thinking out loud here) when you hit a bump the bump steer causes the ski to pull to that direction. This causes the bars to turn a slight amount in the direction of the bump. The inner tie rod mount changes elevation and the tie rod angle decreases in relation to the lower a-arm. I'm now wondering if this is why the sled acts so weird for mountain riders when they sidehill (from the Skins video)? I wonder if this is also contributing to the Nytro head shake?

I've already looked at ways to remount the inner tie rod ball joints, and I'm afraid that it is basically impossible. You were right, in the idea that the tie rods have to be a bit shorter, but I'm afraid that taking 1-1/8" is too short. It appears that somewhere around 1/2"-3/4" shorter is where we want to be. The ONLY way to maintain the tie rod length required is to do some cuttin!

 

[AKrider]

That sucks, but it is good to know. Hopefully the Rev spindles will be very similar to the stock spindles. As long as its toe rod mounting tab is not in the same exact place as the lower tab on the Nytro, I should be able to shim to the sweet spot and see what happens.

You'd think there'd be a reason the guy in the European sno-x photo went through the trouble to mount Rev spindles. Yamaha racing certainly couldn't have done it publicly, of course they ddi run an Polaris IQR rear skid, but that wasn't as obvious.

 

[bulldogbones]

Alright guys I got a question. hen you jack the sled up and one ski is free of the ground how much chatter/play do you have in your upper and lower ball joints??

 

[00-NUKE]

Alright guys I got a question. hen you jack the sled up and one ski is free of the ground how much chatter/play do you have in your upper and lower ball joints??

No Chatter. But I only have 700 miles on the 2011.

 

[00-NUKE]

That sucks, but it is good to know. Hopefully the Rev spindles will be very similar to the stock spindles. As long as its toe rod mounting tab is not in the same exact place as the lower tab on the Nytro, I should be able to shim to the sweet spot and see what happens.

You'd think there'd be a reason the guy in the European sno-x photo went through the trouble to mount Rev spindles. Yamaha racing certainly couldn't have done it publicly, of course they ddi run an Polaris IQR rear skid, but that wasn't as obvious.

I'm sure that ski-doo spindles are set up for their own geometry. That could be a BIG bag of worms!

 

[AKrider]

Yeah, they won't be a direct comparison for sure, but I figured it would be interesting to experiment with them. I'm most curious about the location of the tie rod tab.

 

[00-NUKE]

Yeah, they won't be a direct comparison for sure, but I figured it would be interesting to experiment with them. I'm most curious about the location of the tie rod tab.

I haven't gotten to it yet, but will keep you informed.

 

[AKrider]

No worries, I was referring to the tab on the Rev spindle. I'm thinking its location will be different and may allow for the tie rod to be shimmed to the sweet spot.