shockabsorber Suspension Too Soft!

[EnduroBandit]

Hello,

I have a question about my Dirt Bike's suspension. The bike is an IT200, but the rear shock is from a YZ250. The bike was fully restored by a professional 2 years ago. The suspension front and back is super soft, which is great for going over smaller bumps at high speed. However, the rear shock rebound springs up like a trampoline when I go over big bumps or wups, and it's also pretty easy to bottom out the suspension taking jumps. I tried the adjustments on the rear shock and didn't really notice a difference. Which makes me wonder if there could be no shock absorber fluid in there? Is this just how the suspension is on these old IT's? My '89 KDX200 has tired suspension and it handles wups much better. The rebound on it is what I expect from a dirt bike. Any help would be great! 

[TN Dirt Rider]

How big are you?  What size spring is on the shock?  How about in the forks?

You likely need a rebuild of the shock, but need to start of making sure you have it sprung appropriately for your weight.

[EnduroBandit]

I'm 5'11 155lbs.  The front forks are 43mm Kayaba and the rear shock idk how long but it is long travel also. The suspension was rebuilt along with the bike and still feels like it did when I bought it. The front forks aren't adjustable and the adjustments on the rear shock don't seem to make a difference.

[biglake]

Is it the right shock for the bike?

I ask this because some bikes have different leverage ratios, even if a shock bolts on it could be way too soft or stiff.

My 2012 wr250r looks like it has a similar shock/linkage to a yz but it has a 7.7 kg/mm spring on it and the newer yz's have 4.9 kg/mm springs.

[EnduroBandit]

It is a YZ250 shock but very similar and about 1/2 inch longer travel. The guy who restored it is an expert with YZ's and IT's and other bikes so I trust that he knew what he was doing. It does seem to feel very similar to the forks, but the rebound on that rear shock is dangerous.