Hard time changing torsion springs

[cannondale27]

Correct me if I'm wrong, but I think he's figured out that the reason for the difficulty with the rear mounts was due asymmetrical torsion settings. Sounds like that's been corrected and the skid now mounts up without any problems. What I am referring to, and what I think kojack is talking about, is the tendency of the tunnel to sag a little even when the skid is unsprung. Many here have commented on how you can grab the rear bumper and unweight the suspension, only to see it sag when you let go ... That it what I am talking about and I don't believe that it necessarily means your shocks are bad.

You are correct.Most of that sag is just from stiction in the suspension itself.Glad you got it figured out Kojax!

 

[kojack]

Yes I got her figured out, well the bracket part. To make it a bit more clearer:

- Springs are changed from factory MTX springs (1700) to GT springs (2500)
- Hygear Torsions spacers are installed.
- Shocks were never removed from the skid and only have 1700 km on the sled so there's in no way they could be install upside down, unless yamaha screwed up when they put it together at the factory
- If I pull the rear bumper up, It will stay up and will not sag. Springs are set on Hard setting
- If I push down on the rear bumper and squish the suspension down it will maybee spring up 1 inch or so but really slow that you can almost not see it going up.
- All the rear skid was greased and no ice is in the skid as we had warm temperature lately and everything melted in the garage.
- Seems like the shock has way too much rebound and doenst let the springs do their job and preventing them to push the rear back up.
- Previous owner was a little tiny girl and was bought from her dad as a gift. I would be really surprise if the shocks were blown.

 

[blueironranger]

be ready to swap in a different rear shock. I tried the 2500's on my MTX and went back to the factory 1700's and I'm about 200# ready to ride. The 2500 caused too much "Kick" on rebound and made me find out what all the "short track" riders were complaining about. Also according to suspension setup guide The 2500# springs didn't give me enough "sit in" where as the stock 1700 springs actually put the rear scissor exactly half way between the bump stops which is desirable. Do note that I run a Fox Float in the center position and run an effectively higher spring rate in that position than the stock MTX center shock which also helps hold the sled up. I personally feel that the Center shock/spring is FAR more important then rear shock/spring combo on rider forward sleds like the Phazer. the 1700 is definitely weak and easy to bottom out if landing bumps tail heavy but I couldn't stand the "kick back" the 2500 caused and it really took away a lot of the "wheelie" ability from the sled which I like to have in the rough stuff. I'd really like to try a set of 2100 GT springs but haven't found any for cheap yet.

 

[kojack]

With the 2500, the scissors arm is right in the middle like you stated and the shock doesn't spring the tail back up so that's why I'm thinking the rear shock is the culprits. So you say that it would be better to change the front shock of the skid to a fox float one?

 

[cannondale27]

The center shock is doing maybe 25% of work rear is the rest because of coupling and the linkage design.

 

[blueironranger]

The center shock is doing maybe 25% of work rear is the rest because of coupling and the linkage design.

well yes and no. I see how the linkage works and have spent a few hours playing with it and agree that both shocks need to work well with each other but I think its the front shock/spring that does most of the work. Basically how I see the linkage working is that is senses how fast the front/center shock is moving and compresses the rear shock quicker if the front takes a big hit which effectively stiffens the rear shock. Then again I'm the type of rider that lets the front suspension land slightly first instead of being tail heavy when getting air born. I can see the Rear/Rear shock being a lot more important in tail heavy landings. The front/center handles the most weight, meets the bumps head on, controls ski contact were as the rear controls traction, kickback, and helps out on big hits. I find it a fun suspension to play around with and actually think its the best one in Yamaha's lineup for a bump sled. I think we need some snow so we can ride more and debate less.

 

[cannondale27]

I had 3 totally different shock setups in the center position and honestly none made much difference at all.Rear shock changed everything for the better.Trust me spend the cash on best rear shock you can afford and rest will come easy.