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Motorcycle Repair/1981 honda nc-50 express


Hi lazaros,ray again.You didn't mess up.I failed to tell you that the bike has not run since 1984,it only has 444 miles on it! Getting ready to pull the intake,carb off.Can i still check the compression? with the carb off,Can i check compression with intake manifold off? As always,i truly appreciate all your help!!By the way i live in southern california,where in greece do you live? Talk to you soon THANKS! ray

Hello Ray,

You can check compression with the carb off, but the reed valve and the manifold must be attached.
Since the bike hasn't been ridden for so long, you should poor some two-stroke oil (10-20ml) through the intake, remove the spark plug and hit the kick-starter continuously, until you see oil spray coming out of the spark-plug-hole.

During that, close the carb manifold with your palm, to see if there is adequate suction.
If you don't have a compression gauge, just cover the spark-plug hole with your thumb while
hitting the starter. If you can't hold the pressure and your thump keeps popping like a
champagne cork, the compression is practically enough for the engine to fire.

Bear in mind that, due to all these years of left unused, many thing can be wrong.
Piston rings and cylinder wall rusted, crankshaft seals hardened, ignition switch shorting, to name the most common and troublesome. Even the exhaust could be clogged by some "evil" insect
that builds it's nest in small openings and holes, with mud!!!
The same uninvited guest, may also pay carburettor-breathing-hoses a visit!!!

Closing, let me remind you to completely disconnect ignition switch when trying to start the
motor. The switch kills the ignition, by shorting the ignition coil to ground, thus when disconnected, the ignition functions normally.
Needless to say, you should replace the spark plug with a new one...
Good luck.

Best Regards,
Trikala - Thessaly, Central Greece.

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Lazaros Ampatzidis


I can help you on EVERY issue involving POST-1980 Japanese Motorcycles plus KTM and Husaberg. My field of expertise includes Engine, Transmission, Fuel system (carburation & EFI),Electrics and Electronics. Maintenance, repair and tuning. Road and off-road suspension tuning. Please don't ask me about non-Japanese Motorcycle, especially American built on which I have low to zero experience.


I'm a rider and hobbyist since childhood. 25 years motorcycle workshop mechanic.15 years motorcycle racing mechanic. In order of experience high to low:Kawasaki,Suzuki,Honda,Yamaha,KTM,Husaberg.

Hellenic (Greek) Technical School.Internal Combustion Engines Engineer. Automotive Electronics.

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