Quicksilver MX drive failure, Quicksilver MX root tube bearing failure.

Aircraft:
EIPPER QUICKSILVER MX

Problem area:
Collar located inside root tube

Incident report:
Various MX pilots have reported vibration in their aircraft, upon further examination it was found that a collar inside the root rube which the top pulley shaft goes through had begun to wear, allowing the bearing which it retains to move causing the vibration.
It was generally found that all these aircraft had more than 100 hours on them.

Suggestions:
Drill a hole through the root tube directly in front of the bolt that holds the collar and install a bolt. What this does is holds the collar in place and takes the strain off of the bearing and collar. Of course if you have already started to feel the vibration then the bearing is probably gone and must be replaced.

If you have access to a machine shop the suggested retrofit below replaces the round bearing retaining collar with a new aluminum insert which fits snuggly into the root tube eliminating the need to drill the second hole, and prevents bearing and collar wear in the future.