not getting compression on honda 70cc

merlin311 /

i just got a honda passport from a friend it needs work but.the first thing is when i go to kick start it im not getting anything.its been sitting awhile i put fresh gas and oil in it.

Re: not getting compression on honda 70cc

is it a 4 stroke engine? Most times when an engine sits for a long time one of the valves can get stuck open due to rust. Obviously when the valve is stuck open the compression goes right out through that valve.

Usually that stuck valve ends up getting bent. As the piston rises toward it ...it is supposed to be closed but it isn't. The piston slams into it over and over bending it.

If it's a 2 stroke my guess would be your piston and rings are bad.

Re: not getting compression on honda 70cc

is it a 4 stroke engine? Most times when an engine sits for a long time one of the valves can get stuck open due to rust. Obviously when the valve is stuck open the compression goes right out through that valve.

Usually that stuck valve ends up getting bent. As the piston rises toward it ...it is supposed to be closed but it isn't. The piston slams into it over and over bending it.

If it's a 2 stroke my guess would be your piston and rings are bad.

Re: not getting compression on honda 70cc

merlin311 /

yea its four stroke.ill be taking it to a friend later maybe he can figure out whats wrong with it.

Re: not getting compression on honda 70cc

Ron Brown /

Take out the spark plug and squirt a shot of engine oil on the high side of the piston. Just enough that it flows all the way around the edge of the piston. If this gives you good compression, your rings are stuck. If not, you most likely have a stuck valve. Check the valve clearances to figure out which one it is, then remove either the exhaust or intake so that you can see the valve stem and you may be able to oil it and kick it over enough to free it up.

Ron

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