need advice on fixing laura M 56 engine

I recently purchased a 1978 Batavus Regency. It's great except that it doesn't run. It does have spark, I'm not sure about the timing but the flywheel has two marks drilled into it; one lines up with TDC and the other comes a little before that. Fuel is getting to the carb and i have dipped it twice. The engine has compression although I'm not sure if it's high enough. When I try to start it nothing really happens except if I jump off and pull the plug right away a little bit of smoke comes out of the plug hole. Any advice would be greatly appreciated.

Re: need advice on fixing laura M 56 engine

99 times out of a hundred, an old bike that's been sitting around suffers from a carb / fuel delivery troubles. Eliminate this possibility before suspecting ignition or compression problems.

Start with a new spark plug.

Examine the condition of the tip of the spark plug after failure to start. Is the tip wet or dry?

If it's tip is all wet it's either fouling on too much fuel or the spark is too weak or it's just an old dead plug.. Weak spark can be cause by lots of things, from improper spark plug gap to some fault with ignition wires or components.

If the plug comes out dry, no fuel is getting into the cylinder.

Spray a bit of Starter fluid into the carb's intake or spark plug hole and reinstall.. if it fires up it tells you spark exists but no fuel is getting in.

If Starter Fluid doesn't fire it tells you spark is lacking. Starter fluid (Ether) instantly vaporizes and will fire at sub-zero temperatuires without compression so that test doesn't tell you if the head bolts are so loose you don't have any compression.

Re: need advice on fixing laura M 56 engine

Don Pflueger /

the encarwi carb is a simple carb to clean our. make sure the reeds are clean and seated properly. there is also a service limit on the reeds, i think its .005" or so, i'd have to look thru my shop manuals. you need to have about 120 lbs of compression. make sure the decompression valve is sealing. also check for spark and inspect your plug as joe suggested. another good thing to look at is the exhaust port and pipe. make sure they are clean. that engine wont run without the air box either. make sure its on tight. there is a service manual for this engine at in the moped repair section.

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