ST2-ST4 dog-bone same as 749/999 ?

[phantomaz]

Hello guys ,are those two linkages same ,or there are some differences? On the pictures they look the same ,but the serial number is different 73210031 vs. 73210034 or ..32 . I am planning to do the 749/999 swingarm swap , I have all the parts except the dogbone. Anyone ?

[Raux]

it will fit? the 999 cases are narrow cases (with bearing in swingarm), the st2/4 wide cases (with bearings inside)

[phantomaz]

It won't be direct swap ,a lot of modifications will be required , but my question is about the dogbone/shock linkage/ st2 vs 749, are they the same?

[Raux]

sorry. all i know is the st2 and s2r are the same.

[phantomaz]

yes ,they have the same serial numbers. thanks!

[krista]

I just looked at S2R1000 and 749 that are here. The Monster dog-bone looks longer. It is also starting at a different angle... it points down at the front 30+ degrees. The 749 one is pretty much flat with the ground.

[phantomaz]

Thank you very much chris, that's what I needed. On the pictures they looked the same ,and I wondered where the difference is, this one helped a lot , because I was almost ready to buy the st2 linkage. Best regards!

[MonsterHPD]

As it happens, I´ve been looking into this in some detail over the years, and a bit more focussed lately since I need to design a linear linkage for the tracSTer track-day bike.
I do not have all the facts (of course ...) but below are a few facts for the different links I´ve checked. The different bikes have different wheel travels, shock travels and leverage ratios; all rockers have a "positive gullwing" shape except for the 749R / 999R "linear" rocker, which is "negative gullwing"

As it turned out, I´ll have to design a custom rocker for the tracSTer, but that´s another story.

The dimensions below are as accurate as I could make them without access to a proper measurement machine, whatever they´re called, but should be generally accurate enough to see the differences. I hope the table comes out reasonably readable, the forum would not copy an excel table properly.

     

Model   Model year...Marking................Rod-pivot...Pivot-shock...Angle Shock-pivot...Wheel travel...Shock stroke
M900    2002...........372.1.003.2A........53mm      75mm            23.5°.............148 mm........ 65mm   
ST4S...         
S2R...         
999 Bip.....................372.1.003.1A.........53mm      68mm            19°................128mm..........71mm   
749/999R..................372.1.025.1A.........60mm      58mm           -21°................128mm..........56mm   

Edit: Well, close to reasonable ...
EditII: Slightly better ....   
EditIII: I´ve added wheel travel and shock stroke, will give a hint as to what fits where. I checked the linear 749R link in the Monster, but that would give very strange caracteristis, and shock stroke would have to be shortened.