dirtbike problems?

Question

okay pepsi have a questioni have a 1983 honda xr 80 for some resaon my compression just went out when i put the compressor test on it and i thought the gears might of came out of place so its njot turnig the engine but some help would be nice

its a 4 stroke

its a 4 stroke

its a 4 stroke

Answer 1

Your question is a little confusing.
You had compression, but lost it when you put the tester on it to check?
Could be a bent valve. Or one is so tight that the compression is leaking past it.
Remove the spark plug and bring the piston to TDC of the compression stroke (both valves closed - remove the valve cover to check).
Blow in the spark plug hole with an air gun and compressor and listen at the muffler & air box.
If you hear any hissing, that valve is leaking (needing adjustment or valve job).
When you press the kick start lever, does the piston go up and down?
The kick start gears or mechinizim may be messed up.
Put the bike in gear and push it.
That should move the piston.
Check the compression that way (by push starting it with the gauge in the plug hole).

Answer 2

If it lost compression, the rings probably went on it and you will have to rebuild the top end. This happens a lot with 2 strokes, especially the old air cooled ones like you have.

Take the head off and look at it. If the rings actually broke and got pounded into the piston, the cylinder will need to be bored out. if the rings are just worn out and feel sharp wehn you run your fingers over them they are bad, and you can get away with a standard size wiseco piston and ring.

Best bet is to bring it somewhere and they can determine the extent of the damage. The main crank bearings may be worn causing play which caused the whole problem.

Answer 3

You have probably hit the compression release button on your compresion tester. Try putting the spark plug back in and starting it. Or try putting it in gear and rolling the bike, it should turn over.