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Inspecting reed valves

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canam1

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"I recently installed boyesen

"I recently installed boyesen power reeds on my 94 johnson 140 shortly after the engine blew one piston. I dont attribute it to the reeds neccesarily but after dissasembling the motor and looking at the reed cages into the light there is some light getting through. Are they supposed to be completely closed or is it ok to have a little bit of a gap? The gap is about the thickness of a sheet of paper, maybe two. I did follow the instructions and resufaced the reed blocks before installing the new reeds. I am worried to rebuild the motor and have it blow again. Thanks for any input."
 
"preferably,any reed valve ass

"preferably,any reed valve assm,should be compl closed....however...a slight amt would be ok,as back pressure will shut it.now if u modified the reed block....thats another story,or area of prob's."
 
well the instructions for the

well the instructions for the reeds said to use three different grades of sand paper on a piece af glass to make sure that the reed blocks were completly flat. the final sand paper was 600 grit. would a gap cause a lean condition if it was too big. Is it enough to run soo lean that it would wause piston failure.
 
"By memory i think the allowab

"By memory i think the allowable gap was two thou, the boysen reeds did not cause the blow up.

Take a photo of the blown piston and post it we could give you some idea why it blew.

Running lean on one carby high speed jet can cause it, timing can cause it, poor quality fuel, overloading the engine, water ingression through a head,exhaust plate or base gasket can cause it. Even the wrong heat range spark plugs."
 
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