White Smoke From Exhaust Muffler; Cylinder And Piston; Compression Too Low Or Uneven Compression; Excessive Smoke From Exhaust Muffler - KYMCO Downtown 350i Repair Manual

4.Engine

White smoke from exhaust muffler

• Worn valve stem or valve guide
• Damaged valve stem oil seal

Cylinder and Piston

• The cylinder and piston cannot be serviced with the engine installed in the
frame.
• After disassembly, clean the removed parts and dry them with compressed air
before inspection.
• If replacing the piston or cylinder, they must be changed as a pair.
TROUBLESHOOTING

Compression too low or uneven compression

• Worn, stuck or broken piston rings
• Worn or damaged cylinder and piston
Compression too high
• Excessive carbon build-up in combustion chamber or on piston head.

Excessive smoke from exhaust muffler

• Worn or damaged piston rings
• Worn or damaged cylinder and piston
Abnormal noisy piston
• Worn cylinder, piston and piston rings
• Worn piston pin hole and piston pin
Downtown 350i
4-4