it turns out that suspension matters...

hardrockminer wrote:

Lost my reply somehow.  Here it is again.

Thank you for watching the video.  Resonant frequency is the salient point.  The energy input for the bridge was the wind but it could be any source.  On a motorcycle it is the combination of suspension, center of mass and tire pressure.  Change any of these variables and you will change the resonant frequency to a different speed.  
 

Wookie58 wrote:

With regards to the suspension mods - take a breath and do some research- you will Ned access to a lathe, a friendly machine or plenty of money. A lot of the bikes you see with these conversions are badly engineered death traps that are inherently unstable. Pretty much all the later sports bike front ends are too short and fitted as they are will make tank slappers a regular occurrence. This means they need extending/adapting to work as intended and retain reasonable geometry. I am using 98 ZX9R RWU forks in my 82 Ltd and they needed 70mm extensions to retain the geometry with a 17 inch wheel (also ZX9R) these parts aren’t available off the shelf so you will need to tell the machinist what you want. You will also need a modified/custom stem. Don’t want to be a kill joy but if you get it wrong you will be back in the emergency room or worse. There is a lot more to it than bolting parts on !!!!

bound wrote:

Wookie58 wrote:

With regards to the suspension mods - take a breath and do some research- you will Ned access to a lathe, a friendly machine or plenty of money. A lot of the bikes you see with these conversions are badly engineered death traps that are inherently unstable. Pretty much all the later sports bike front ends are too short and fitted as they are will make tank slappers a regular occurrence. This means they need extending/adapting to work as intended and retain reasonable geometry. I am using 98 ZX9R RWU forks in my 82 Ltd and they needed 70mm extensions to retain the geometry with a 17 inch wheel (also ZX9R) these parts aren’t available off the shelf so you will need to tell the machinist what you want. You will also need a modified/custom stem. Don’t want to be a kill joy but if you get it wrong you will be back in the emergency room or worse. There is a lot more to it than bolting parts on !!!!

I changed my mind pretty quickly!!! I started adding up the cash amounts for everything and WOW! It just adds up like crazy and the mechanical calculations and work id need is beyond me. I still want to upgrade in some way so I'll be looking at more mild kz1000 police forks instead with their 300mm rotors. I think that's a lot more achievable. I have this problem where my brain gets excited and thinks of things a lot differently from what they actually are

Your CSR has "leading axle" forks so switching to a "P" would also require the "P" trees or the "Trail" will be excessive and effect the steering. As long as they are straight the best bet would be to re-bush the stock units (or some from a Ltd) fit progressive springs and possibly heavier oil (how heavy are you) then blank off the "air ports" if it has a balance pipe