Servicing your R11XXRT or K1200LT Rear Shock Preload Adjuster

My riding buddy Roger told me he was considering a new rear shock on his LT. It seems his preload adjustment wasn't working like it used to. I brought him to my house and we refilled his preload circuit in about 15 minutes the other day. Now he has the full range of preload just like when his bike was new.

The hydraulic preload adjuster on your LT or RT 'can' cause a problem with ride height. I've found several RT rear shocks that have lost their original range of adjustment. What happens is the hydraulic jack oil in the preload circuit seems to evaporate just a little over time. I've refilled 3 of them and restored the full range of adjustment in each case.

The easiest way to test for this is to back off the adjuster knob till you feel the resistance go away. That is the point where the hydraulic adjuster ceases to adjust anything. If the point of no resistance isn't up near the top (soft) end of the adjustment knob, turn the adjuster FULLY counter clockwise and remove the adjuster from it's mounting bracket. Unclip the hose retainers. While holding the adjuster upside down, remove the banjo fitting at the adjuster and keep the hose end vertical so no oil seeps out. Ensure the adjuster is Fully counter clockwise all the way and stick a nylon rod or something similar in the hole where the banjo fitting attaches and push the piston all the way back. Keep the adjuster upside down during this entire process.

Next you add jack oil to the adjuster piston until it runs out. Re-install the banjo fitting (with new crush rings if you can find them but I've never had one leak) and before you tighten the banjo fitting, twist the adjuster knob clockwise about a quarter turn to eliminate any air bubbles.

Check the adjustment range. If you were low on jack oil, it WILL be much better. This may save some folks the price of a new rear shock. I found hydraulic jack oil at my local auto parts store years ago for refilling my floor jacks.  This oil is totally separate from the shock absorber function.
 

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