raginyamaha
TY 4 Stroke Master
Anyone measure the same stuff on a doo or cat or pol??? itd be interesting to see the differences in bump steer and camber/caster angles and such. o yea- 
Supersled,
Maybe, maybe not. The Nytro does not handle or track through the bumps anywhere near as good as the other makes of sleds. For my style of aggressive riding the Nytro is flawed. For just going slow down a trail then the Nytro will work fine. Than again, so will my daughter's '03 Indy Lite.
Ragin,
That's a great idea but I don't have access to another modern, a-arm sled.
Maybe, maybe not. The Nytro does not handle or track through the bumps anywhere near as good as the other makes of sleds. For my style of aggressive riding the Nytro is flawed. For just going slow down a trail then the Nytro will work fine. Than again, so will my daughter's '03 Indy Lite.
Ragin,
That's a great idea but I don't have access to another modern, a-arm sled.
AK, in reference to Quad's made me start thinking again. Then I just happened to park next to one at lunch today.
The big difference I see is that the tie rod is mounted a couple inches in from the spindle to compensate for the cental mounting point.
As to over thinking it, I agree for the bump steer. But to not call the Nytro front end flawed I don't agree with. Looking at all the Nytro front end threads on Yamaha forums is like looking at CFI engine failure threads on a Polaris forum. There is a million with a million different "theories" or "fixes"
The big difference I see is that the tie rod is mounted a couple inches in from the spindle to compensate for the cental mounting point.
As to over thinking it, I agree for the bump steer. But to not call the Nytro front end flawed I don't agree with. Looking at all the Nytro front end threads on Yamaha forums is like looking at CFI engine failure threads on a Polaris forum. There is a million with a million different "theories" or "fixes"
Oh no, it's another Yamaha front end! 
Good point on the inner tie rod positioning. Like we'd discussed yesterday, Yamaha corrected the tie rod mount on the 09's. It defintely looks like the right approach. Once we get some '09 toe out measurements we hopefully determine what's happening.
I spoke to my racing buddy (who has actually met and worked with the Yamaha engineering team) and his thoughts were that Yamaha just didn't spend enough time designing the front ends on both the Nytro and Phazer. So that leaves the possibility open that we can improve it. That is good.
The bad is he said he felt the engine was too forward and high up in the chassis. In addition he believed the extra weight on the Nytro will prevent it from ever being as good handling of a sled as a comperable 2-stroke. But to frame his point of view, he is looking at things from the stand point of a racer and that it is much easier to just buy a Polaris IQR. I'm not comparing the Nytro to a race sled and I don't think anyone else on here is either. If we were able to get the Nytro to handle even close to 70% as good as a Polaris Rush, than we would have a drastic, night and day improvement.
Good point on the inner tie rod positioning. Like we'd discussed yesterday, Yamaha corrected the tie rod mount on the 09's. It defintely looks like the right approach. Once we get some '09 toe out measurements we hopefully determine what's happening.
I spoke to my racing buddy (who has actually met and worked with the Yamaha engineering team) and his thoughts were that Yamaha just didn't spend enough time designing the front ends on both the Nytro and Phazer. So that leaves the possibility open that we can improve it. That is good.
The bad is he said he felt the engine was too forward and high up in the chassis. In addition he believed the extra weight on the Nytro will prevent it from ever being as good handling of a sled as a comperable 2-stroke. But to frame his point of view, he is looking at things from the stand point of a racer and that it is much easier to just buy a Polaris IQR. I'm not comparing the Nytro to a race sled and I don't think anyone else on here is either. If we were able to get the Nytro to handle even close to 70% as good as a Polaris Rush, than we would have a drastic, night and day improvement.
The problem is the engine can't be any lower and at most without the cooler could be only like a inch back. It's not a trail sled but I'll have a polaris geometry Nytro you can ride this winter 
raginyamaha said:Anyone measure the same stuff on a doo or cat or pol??? itd be interesting to see the differences in bump steer and camber/caster angles and such. o yea-
The 600 RS race sled has virtually no bump steer.
rlcofmn,
That sounds great! Your sled has a ton of potential.
RJH,
That is good news and it settles two things. One, a sled can be built with close to zero bump steer and two, its tie rods are angled just like a Nytro.
http://fiche.worldofpowersports.com/wps ... A=905&B=17
I've been thinking about another way to study the Nytro geometry. If a guy has enough space in his shop, he could take string, fasten it to the pivot points of both the a-arms, and stretch it out along the a-arms to the string intersected the ball joints. From there, keep stretching the strings until they cross paths. Now do the same thing with the tie rod. If they all intersect at one point than that is the instant center. I suspect they will not intersect.
That sounds great! Your sled has a ton of potential.
RJH,
That is good news and it settles two things. One, a sled can be built with close to zero bump steer and two, its tie rods are angled just like a Nytro.
http://fiche.worldofpowersports.com/wps ... A=905&B=17
I've been thinking about another way to study the Nytro geometry. If a guy has enough space in his shop, he could take string, fasten it to the pivot points of both the a-arms, and stretch it out along the a-arms to the string intersected the ball joints. From there, keep stretching the strings until they cross paths. Now do the same thing with the tie rod. If they all intersect at one point than that is the instant center. I suspect they will not intersect.
00-NUKE
Expert
AKrider said:Oh no, it's another Yamaha front end!
Good point on the inner tie rod positioning. Like we'd discussed yesterday, Yamaha corrected the tie rod mount on the 09's. It defintely looks like the right approach. Once we get some '09 toe out measurements we hopefully determine what's happening.
I spoke to my racing buddy (who has actually met and worked with the Yamaha engineering team) and his thoughts were that Yamaha just didn't spend enough time designing the front ends on both the Nytro and Phazer. So that leaves the possibility open that we can improve it. That is good.
The bad is he said he felt the engine was too forward and high up in the chassis. In addition he believed the extra weight on the Nytro will prevent it from ever being as good handling of a sled as a comperable 2-stroke. But to frame his point of view, he is looking at things from the stand point of a racer and that it is much easier to just buy a Polaris IQR. I'm not comparing the Nytro to a race sled and I don't think anyone else on here is either. If we were able to get the Nytro to handle even close to 70% as good as a Polaris Rush, than we would have a drastic, night and day improvement.
Thank you all for the imput on the tie rod change. Very possible, the fact that repositioning the tie rod aft forcing the tie rod mounting point to go lower on the spindle may have been the improvement. I still haven't taken measurements for that change, but here is what I've found so far.
My stock 2011 measurements are as follows.....
36.7mm (1.44 in) of scrub @ 75% compression
15mm (.59 in) of bump steer (toe out) @ 75% compression
25mm (.98 in) of scrub @ 50% compression
8.3mm (.33 in) of bump steer (toe out) @ 50% compression
After 14mm Mod
36.55mm (1.4 in) of scrub @ 75% compression
12.88mm (.51 in) of bump steer (toe out) @ 75% compression
25.08mm (.99 in) of scrub @ 50% compression
8.25mm (.32 in) of bump steer (toe out) @ 50% compression
As you can see the 14mm mod made a very small improvement on the scrub or bumpsteer, but seemed to make a considerable improvement in handling?????? The journey continues. :exc:
00-NUKE
Expert
AKrider said:
After reviewing my measurements, I believe AK hit it on the head. I think the tie rod has to be mounted right where the lower tab is. My measurements are showing a steady increase of toe out throughout the suspensions transition from full extension to full compression. By lowering the tie rod a little bit, you are aligning the tie rod with the lower A-arm. I have an extra set of 2009 spindles. I will be removing and adding a new lower tab to these and seeing what my results are. That HAS TO be it!
Great, now we know the '09 geometry toes out and the front end still has bump steer, but a smaller amount than the '08. My thoughts are the 14 mm mod reduced the amount of camber change and decreased the bump steer. This is why the sled felt better in the stutters.
I'm thinking the '09 tie rods are still too long. It would be interesting if you could turn he tab you made 90 degrees to face the subframe of the sled, spin the tie rod shorter, mount it and see what happens as you compress the suspension all the way through the entire stroke. I was seeing toe in at the top of the stroke.
I'm thinking the '09 tie rods are still too long. It would be interesting if you could turn he tab you made 90 degrees to face the subframe of the sled, spin the tie rod shorter, mount it and see what happens as you compress the suspension all the way through the entire stroke. I was seeing toe in at the top of the stroke.
Before you permanently alter your '09 spindles, try the bolt on tab idea. You could also grind the collars off your tie rod end and shim to see what happens. That part is a lot less expensive to replace!
00-NUKE
Expert
AKrider said:Before you permanently alter your '09 spindles, try the bolt on tab idea. You could also grind the collars off your tie rod end and shim to see what happens. That part is a lot less expensive to replace!
That is an AWESOME idea! Luckily I have an extra set of tie rods as well. I picked up the whole 2009 front suspension when I had a 2008 and was smart enough to switch it back before letting the 2008 go. I'll get on that by next week. We just had a BAD storm come through and take down some trees, so I have to take care of buisness before pleasure. THANKS AK! I feel like I'm getting somewhere with this.
Glad I can help. Rlcofmn sent me the measurement to try the tab idea on my '08. I thought it was a good idea as well.
If the shorter tie rod and shimming the tie rod end doesn't show improvement then we'll need to shift our attention to the inner tie rod mounting points.
If the shorter tie rod and shimming the tie rod end doesn't show improvement then we'll need to shift our attention to the inner tie rod mounting points.
00-NUKE
Expert
AKrider said:
Sounds like a plan. I don't even care if I completely remove the bump steer. If I could cut it in half, I would be besides myself!
I just noticed your toe in at the top comment. In case you were wondering why my measurements stopped at 75%.....
I'm not too concerned with the bump steer being a little off at full compression of the suspension, just for the fact I run my suspension pretty stiff and rarely hit rock bottom when I'm scootin'. I'll be sure to take measurements all of the way through after I can get somewhere with this project.
