1. Check rings and pistons after 100 hours engine time.

1. Remove exhaust collector internal hex bolts 6mm
2. Examine gaskets - replace if required (RTV may prolong gasket use) Part. 831-843
3. Swing muffler out of the way.
4. With a light examine the piston skirt. Rotate crank to see the entire piston. Skirt should be shinny with no visible scuff or streak marks. Discoloration is ok as long as it is not crusted carbon. Apply some WD-40 to the rings. Rock the crank. If the rings are free there should be some movement of the rings causing WD-40 to squish out slightly. Carefull application of a blade screwdriver may also be a way of determining ring freedom

1. If rings stuck:

1. Remove head bolts 13 mm
2. Remove screws around base of shroud and remove shroud. Inspect for damage and corrosion.
3. Remove spark plugs and inspect. Choc brown electrodes is desired. Discard plugs
4. Mark and remove heads. Clean piston cavity if required. Do not remove metal.
5. Insure no foreign material gets into crankcase. Install rags or shop towels in the case openings and put an additional layer beneath piston.
6. Clean piston crowns if carbon is present. If smooth to the touch no aggressive cleaning required.
7. Mark and remove cylinders

1. Examine piston barrel for hatch markings. If visible and no scratches set aside. I scratched or hatch marks worn away re honing is required.

1. Carefully remove rings and keep with cylinder
2. Clean ring groves. Broken ring works well. Generous applications of carburetor cleaner works well here.
3. Clean rings. Do not alter ring geometry or outer ring surface. The tops and bottom surfaces should be clean down to bare metal. Do not remove any metal.
4. If skirt of piston needs cleaning do not remove any metal.
5. Clean cylinder base.

1. Place base gasket on case. 831-855
2. Slip froward (MAG END) cylinder on to pistons.

Do not force rings.

3. Do the same for PTO end.
4. Place exhaust alignment tool on exhaust surfaces
5. Replace cylinder heads and finger tighten head nuts.
6. Torque to specifications and pattern. 105/150/195 in. lb.
7. Replace shroud. Do not tighten screws until exhaust brackets are secure.
8. Remove exhaust tool and replace exhaust headers.
9. Install new spark plugs .016 to .020 gap
10. Inspect engine for security.
11. If cylinders honed or new rings installed , run engine in as per Rotax specs.
12. Run engine and inspect for leaks.

-Socket wrench

-Torque wrench

-13 mm socket

-6 mm hex wrench

-Screwdriver

-Broken Rings 2

-Carb Cleaner

-Abrasive pads (scotch bright)

-Plug socket 14 mm

-Anti seize for plugs

-Shop towels

-Exhaust tool

-Locktight

-Broken Rings (2)

-Brass wire brush (small)

A complete manual is available from:

Microflight Products

16141-6 Pine Ridge Rd.

Fort Myers Florida

813-454-6464