Step#1   Remove small cog sprocket (secondary) excursion ring.

Step#2   Relieve tensioner idler pressure.

Step#3   Remove cog belt from both sprockets. Recommend using short piece of 2X4” block. Work belt upwards while slowly rotating assembly.

Step#4   Disconnect “H arm” pivot from airframe hood. Remove two bolts.

Step#4   Remove rotor-tach bracelet. Careful to not lose small screw and nut!

Step#5   Remove Breeze clamps and two-piece shaft spacer from mast. Clean grease from shaft & spacers.

Step#6   Loosen Allen lock screw and upper bearing locking collar. Place drift punch in collar recess and strike in direction opposite of shaft rotation.

Note: Hit only hard enough for collar to drop! Remember that the collar can lock in either direction!!

Step#7   Remove the two Carriage bolts on lower bearing mount upper half.

Step#8   Slightly loosen the four bolts on the upper bearing retainer. This will allow limited mast movement if necessary to slip cog belt between lower bearing and square tube.

Step#9   Lift mast just enough for the cog belt to be removed from the bottom.

Note: Two short fan belts around the mast “knuckle” using a crane to lift the whole assembly.

Step#10  Remove cog belt. Verify that there is enough room as to not damage the belt.

Step#11  Install new belt careful not to score the cog face.

Step#12  Lower rotorhead assembly back into position. Reinstall the two Carriage bolt on lower bearing retainer.

Step#13  Torque the upper bearing four retention bolts.

Step#14  Align cog belt with both sprockets and using the 2X4” block tap down while rotating system.

Step#15  Re-tension idler sprocket.

Step#16  Reinstall upper “H arm” for collective pivot.

Step#17  Install upper bearing locking collar. Strike collar in direction of shaft rotation. Set Allen screw lock.

Step#18  Rotate cog assembly and verify tracking on small cog sprocket. Adjust as necessary.

Note: Recommend taking ship outside and with a qualified observer do a low RPM run up to verify tracking. Never go above 2000 RPM without main blades installed!

Step#19  Install small sprocket excursion ring.

Step#20  Reinstall the two piece mast spacer. Lightly apply grease to the shaft prior to installation with Breeze clamps.

Step#21  Align and reinstall rotor-tach bracelet. Careful with the small Brass screw and nut. Verify clearance with sensor @1/8”.

Note: First time run up with blades pulling power observe belt tracking. The “Blue” dust is mold release and will eventually wear off. After short run check temperature of excursion ring. If seems too hot remove ring and do a second run up. If not familiar with adjusting tracking call someone knowledgeable!