Finally got around to comparing the first and second gen frames. The results are interesting and I can see why Yamaha wanted to make some changes.
The first gen has a narrow lower frame with the a arm spacing being about half of the second gen but there is zero recession angle. While the more neutral frame could provide lower bump steer, the 0 recession angle will make it harder for the suspension to actually absorb sharp impacts. The danger with the 0 recession angle is you have to pay a lot of attention to suspension heights. If the rear suspension is taller with say a 660 shock your frame recession will actually go negative. This means if your tire were to hit something like a rock the suspension will be compressing into the impact instead of away making the impact feel sharper. The second gen has a 7 degree which is closer to more modern Yamahas.
Another interesting observation is that the upper a arm mounts are narrower in the rear vs the front. This means Yamaha designed in caster gain so the upper ball joint actually travels back as the suspension compresses up.
The rear swingarm mount of the first gen is a little bit lower in the frame than the second gen and more in line with the sprocket. By moving the mount upwards you create what is call anti squat as the force from the chain is trying to pull the rear tires down while also trying to spin them. I hypothesize Yamaha made this change along with the shorter swingarm to lighten the front end.
Overall I think both chassis have their pros and cons. If you look at it from a handling and steering perspective I think you'll find benefits in the first gen. When it comes to ride though the second gen will take the advantage.
Lastly I was able to compare these to my raptor 700 which is similar to the carb yfz. What I found is this was actually similar to the second gen frame. The upper mounts and frame recession were about the same. The only differences were the lower mounts were about 1" further apart on the warrior and the upper shock mount roughly 5" more narrow on the warrior. I think if you can move these mounts slightly you could easily mimic the raptor geometry.
Next will be paying attention to the steering flag geometric as I have a feeling that is where some issues come up with the warrior.
The first gen has a narrow lower frame with the a arm spacing being about half of the second gen but there is zero recession angle. While the more neutral frame could provide lower bump steer, the 0 recession angle will make it harder for the suspension to actually absorb sharp impacts. The danger with the 0 recession angle is you have to pay a lot of attention to suspension heights. If the rear suspension is taller with say a 660 shock your frame recession will actually go negative. This means if your tire were to hit something like a rock the suspension will be compressing into the impact instead of away making the impact feel sharper. The second gen has a 7 degree which is closer to more modern Yamahas.
Another interesting observation is that the upper a arm mounts are narrower in the rear vs the front. This means Yamaha designed in caster gain so the upper ball joint actually travels back as the suspension compresses up.
The rear swingarm mount of the first gen is a little bit lower in the frame than the second gen and more in line with the sprocket. By moving the mount upwards you create what is call anti squat as the force from the chain is trying to pull the rear tires down while also trying to spin them. I hypothesize Yamaha made this change along with the shorter swingarm to lighten the front end.
Overall I think both chassis have their pros and cons. If you look at it from a handling and steering perspective I think you'll find benefits in the first gen. When it comes to ride though the second gen will take the advantage.
Lastly I was able to compare these to my raptor 700 which is similar to the carb yfz. What I found is this was actually similar to the second gen frame. The upper mounts and frame recession were about the same. The only differences were the lower mounts were about 1" further apart on the warrior and the upper shock mount roughly 5" more narrow on the warrior. I think if you can move these mounts slightly you could easily mimic the raptor geometry.
Next will be paying attention to the steering flag geometric as I have a feeling that is where some issues come up with the warrior.
