Shock Upgrade

The stock rear shock with a rating of 420 lb./in. is perfectly adequate for a much lighter rider. But for me, weighing in at 220 lb. or so with gear, it just isn't strong enough to support the weight and respond properly to the road surface. This condition is exacerbated when riding two-up. I upgraded my shock with a 650 lb. spring and had a revalve performed by suspension expert Curtis Pell at California Suspension Works. Curtis also services the shock with new 5 wt. oil and a nitrogen recharge. This does involve removing the stock shock, packing it up, and shipping it to Curtis' shop. At the time of this writing, the total charge for this service including parts, tax and return shipping was about $335. Turnaround time will vary depending on shipping distance but you should allocate about 1-2 weeks of down time. Curtis can be reached at:

California Suspension Works
128 Ada Ave., #9
Mountain View, CA 94043
(650) 968-6144

Even with the stock shock set at near maximum preload and having tweaked all the compression and rebound damping settings, the bike felt like it could do better in predictability and inspiring confidence. I was not disappointed with the result. Now set at the third softest preload setting, the bike is much firmer in a way that the stock shock simply could not deliver. The most noticeable difference is the way the bike more closely tracks all the undulations in the road surface where before there might have been some wallowing and jittering. The idea is to keep the tires in contact with the road surface as much of the time as possible and this upgrade accomplishes that goal.

It is recommended that the front suspension be modified at the same time as the rear shock for balanced performance. I did perform this upgrade at the same time and that description is provided here. The positive improvements achieved are the result of upgrading both the forks and the rear shock at the same time.

For my weight and intermediate riding skills and style, the shock is delivered at Curtis' recommended settings:

PRELOAD: Position 3, 9th softest out of a total range of 11 positions. You should verify that this results in the proper amount of static sag as described in the page on the stock suspension adjustments.

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COMPRESSION DAMPING: 6 clicks in from fully turned out position. The total range is 12 clicks.

REBOUND DAMPING: 3 clicks out from fully turned in position. The total range is 20 clicks. The shock is returned with a nice blue spring replacing the stock red one.

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Remove Stock Shock:

Place the bike on the centerstand, remove the seat and the right side cover.

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Next, underneath the bike, remove, in this order:

  1. Rear (closest to rear wheel) connecting arm (dogbones) bolt and nut (M12 thread, bolt head 17 mm, nut 17 mm).
  2. Loosen, no need to remove, front connecting arm nut (M12 thread, bolt head 17 mm, nut 17 mm).
  3. Shock lower mount bolt and nut (M10 thread, bolt head 17 mm, nut 14 mm).
  4. Relay arm and frame bolt and nut (M10 thread, bolt head 14 mm, nut 14 mm).
  5. Shock upper mount bolt and nut (M10 thread, bolt head 17 mm, nut 14 mm).

To remove the rear connecting arm bolt, you will have to lift the rear wheel slightly to relieve the tension on that bolt as it supports the wheel and swingarm. With the bolt removed, the wheel will drop down to the ground.

All the bolt heads are on the left side of the bike and all the nuts are on the right side. These are torqued tightly and can be hard to remove since the bolt head must be held while the nut is turned. A second pair of hands comes in handy here.

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After you remove the rear connecting arm bolt the swingarm will drop so be careful. After you loosen the front connecting arm nut, you can swing down the connecting arms (dogbones) to access the shock lower bolt and nut. After you remove the relay arm and frame bolt/nut the relay arm is removed. Then you can remove the shock upper bolt. The shock upper bolt head is retained by constraining tabs so there is no need for a holding wrench on that side. Removing that bolt causes the shock to drop down so hold it as you pull out the bolt. The nut is a little tough to reach so I used a universal joint adapter on the socket wrench and accessed it through the right side frame.

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I temporarily reinstalled the bolts and nuts in their respective holes for safekeeping.

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Install New Shock:

Remove the bolts and nuts from their safekeeping positions and remove the relay arm with the front connecting arm bolt and connecting arms still attached.

Insert the shock from the bottom with the compression damping adjustment screw facing the left side of the bike. Attach the top shock mount bolt and nut.

Attach the relay arm to the frame. Then attach the shock lower mount bolt and nut. You must torque it tight to specs at this point. Then attach the rear connecting arm bolts/nut. You will have to raise the swingarm to align the holes.

Torque down the rest of the bolts and nuts. Again, a second pair of hands comes in handy here.

  Tightening Torque
Item Thread Size Nm m-Kg lb-ft
Rear shock absorber (upper)M10404.029
Rear shock absorber and relay armM10404.029
Relay arm and frameM10404.029
Relay arm and connecting armM12484.835
Connecting arm and swing armM12484.835


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Last Updated: 07-02-2004

Copyright © 2001-04, Patrick Glenn, All Rights Reserved.
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The information presented here reflects solely my personal experience with my motorcycle and is presented for entertainment purposes only. No information presented here is to be relied upon for issues of rider safety nor to replace the services of a qualified service technician. Any attempts to follow or duplicate any of these procedures are done so completely at your own risk. By reading the information on this site, you agree to assume complete responsibility for any and all actual or consequential damages that may arise from any information presented herein.