Common Reasons Why Your Moped Is Running Slow



Posted: Friday, July 18, 2008

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If you have replaced your spark plugs, cleaned your ignition points, checked for good fuel flow to the carb, and cleaned your carburetor, and your bike STILL won't run, there are a few secondary reasons why.  Here are the reasons, and how to fix them.  

MUFFLER CLOGGED with CARBON

If your moped is clogged with carbon, it may still start and run, but not very fast.  A moped whose muffler is clogged will usually start and run... but will not run very fast.  If you remove your muffler and the ped runs a lot faster without the muffler on, the muffler is probably clogged.  To unclog it, get it very hot and burn it out.  You can use a coat hanger.  When you are done burning it out, bang out the ash that will be left over after it cools down.  De-carbonizing the residue in here should increase your speed, power, and may even give you up to a 10mph boost.

WORN OUT RINGS and CYLINDER and PISTON

Remove the spark plug and have someone pedal the motor quickly while you hold you finger FIRMLY over the spark plug hole. The piston and rings should compress the air enough to blow your finger right off the spark plug hole. If this does not happen, then your compression is low.  Remove the head and cylinder and look for scuffing on the cylinder and piston skirt.   If you see scuffing like this, then buy an oversized piston and rings and have the cylinder bored to fit them.  If there is no scuffing, tten buy new rings and have them installed properly. 

AIR FILTER

Air filters keep dirt out of your engine.  If the filter gets too dirty, it can decrease engine performance.  If you have a paper filter, blown it off with compressed air or buy a new one. 

LEAKING HEAD GASKET

If you have a leaky head gasket, you may be able to hear some compression squeezing/puttering out past the gasket.  If you look closely between the cylinder and head, you also may see some oil, which tells you that there is a leak.

These are some general troubleshooting guidelines.  If all else fails, read your manual or take your vehicle to an authorized mechanic.  They should be able to do a thorough inspection and point you in the right direction as far as repairs go.
 
Joshua Belden has been a moped and scooter enthusiast for the past 10 years. His recent projects include restoring 49cc mopeds and finding quality cheap mopeds.
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Top-level comments on this article: (1 total)
» left by Anonymous 3 years 123 days ago.
hey i just recently purchased a pinnacle 150 moped and it wont start. i think it has to do with no spark i have replace the plug and tried a new plug wire do you have any tips if so it would be greatly appreciated thanks
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