Introduction to shock upgrades

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Revision as of 01:35, 3 September 2011 by Bokonon (Talk | contribs) (Another Option)

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Any thought of changes to the functional parts of your motorcycle should be carefully weighed before making a buying decision. The stock EX250 shock is produced by Showa for Kawasaki. It is a budget shock with no adjustability and is designed for the "average" beginner to intermediate lightweight rider.

A common misconception is that more advanced shocks are for "racers only". Without a doubt, a higher quality shock will help the bike handle better and provide more comfort and safety. And that's much cooler than neon ;)

You really should be aware that just because a shock is from a larger displacement motorcycle that doesn't automatically mean it's a "better" shock for your EX250. Don't fall for that hype.

Also, a new shock will not cure all handling and riding woes. In order to perform at its optimum, a replacement shock needs to be wisely coupled with careful adjustment, chassis geometry monitoring, quality tires and a properly tensioned chain.

Some factors for replacement shocks are the type of riding done, expected loads, adjustability and budget constraints.

Type of riding: Many street riders just want a "better" shock, perhaps with minimal adjustability. Racers and more aggressive riders tend to opt for a firmer shock that has more adjustability and resists fading under extreme conditions.

Load: The stock EX250 shock is simply not well suited for heavier riders, and can easily bottom out riding two-up or in aggressive cornering over bumps.

Adjustability: Shocks can have several modes of adjustability. The most common are:

  • Preload: Adjusts the initial compression of the rear spring. This determines sag and, to some extent, height. Preload is basically adjusting the length of the shock to match your body weight.
  • Compression damping: Strikes a compromise between soaking up bumps and squatting under acceleration.
  • Rebound: Can sometimes be set correctly before you ride the bike. Bounce down on the seat to judge return rate.
In brief, compression damping controls how much the shock goes up when you hit a bump, and rebound is how fast it recovers (returns to static position).
  • Ride height: Controls the overall length of the shock, but can be built-in to the dogbones or mounting points.

Adjusting a rear shock is an art, and an iterative process. Make small changes, and keep notes on what works and what doesn't.

Budget: Aftermarket shocks can be expensive, reaching $1000. However, there are less expensive solutions for those that do not want or need all the bells and whistles of the high priced shocks and like to get their hands dirty.

A stock EX250 shock measures appx. 12 1/4" "eye-to-eye". Increasing that distance means the bike will ride higher. Decreasing it means the bike will ride lower. In some cases you can modify the new shock's lower mounting point to account for the difference, or, if you're lucky, the new shock may have a built-in ride height adjuster.

It is not recommended to play with the length of the dogbones in order to get a different shock to fit. Racers will sometimes do this, but we won't recommend any shock here in the FAQ that requires dogbone modification.


Another Option

Any shock can be revalved to improve its performance. Buying a used shock and having it reworked may work out for you.

  • Aftershocks performs many suspension-related services.
  • [1] Race Tech] has an EX250J shock rework package.