1991 cr250 melted pison any ideas
#1
1991 cr250 melted pison any ideas
Ok my son was given a 1991 cr250 that needed repairs so I started checking it out and found very low compression so we pulled the head and the piston was melted on the exhaust side at the rings so I ordered a new top end kit from Namura Technologies after putting it together it started fine and I ran it about an hour and then put it up for the night. The next day we ran it for about 2 hours and then the flame arrister came off the silencer and all power was lost the silencer did not have any packing in it. I pulled the spark plug and it appears that the piston must have hit the plug just enough to close the gap so I verified that the plug in it was the wrong one. I then pulled it back apart and the new piston was melted on the same side (exhaust pipe side) but a different spot lower portion of piston melted off please I mixed the gas 32:1 and was running it easy for break in
#2
1991 cr250 melted pison any ideas
It sounds like it is lean, it may have a vacuum leak. Or the jetting is way off. I would look at the intake boot and gaskets (reed cage area) if you dont find any leaks. start with a much richer main jet and work from there. im sure some others on this forum know more about 2 strokes(than me) and will be able to help. good luck.
#3
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#6
1991 cr250 melted pison any ideas
good to see everyone has not forgotton the 2 strokes.. yup, its either lean or not getting enough coolant due to low water level, broken pump or clogged passageways.
1. Do you get a nice blue puff of smoke at shifts? You should get a tiny bit of smoke.
2. Can you put your hand on the cylinder after a 10 minute ride? Should be almost to hot but not burning hot
3. what color was your plug? should be tan but never white
4. A 2 stroke running to lean will have a strange smooth idle, is it tough to start?
Hope this helps, Joe
1. Do you get a nice blue puff of smoke at shifts? You should get a tiny bit of smoke.
2. Can you put your hand on the cylinder after a 10 minute ride? Should be almost to hot but not burning hot
3. what color was your plug? should be tan but never white
4. A 2 stroke running to lean will have a strange smooth idle, is it tough to start?
Hope this helps, Joe
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