Ok,
my explorer died suddenly. Noi problems with the quad, then was driving a long , heard like a grinding sound and nothing. stalled out and will not go again. got fuel, got spark but no go, she cranks over fine but will not go. what should i check and what could be the issue?

 

sounds like a seized piston with a broken rod. check for compression

 

Yep, check compression. Bet she's shot...the good news is they aren't hard or expensive to rebuild.

 

Definately need to know what compression is first.

One other thing to know is if you have compression but still wont start, is to remove the carb and reed cage and visually look in the cylinder at the piston and see if the skirt is broken. The 350's and 400's had a tendancy to break the skirts. Around here anyway. I have had machines that DID have enough compression to run, but the skirt was broke and that effects fuel delivery, plus the possibility of serious air leaks from cracks, etc.

Not always, but a lot of times the broken parts would get lodged between the crank weights and the crankcase and it would break the crankcase in various spots. One place I saw the crankcase break frequently was on the right hand case, just under the carb. You could visually see the crank weights from outside the motor. They didn't all break there, but several did.

 

what should i read for compression?
can i simply screw in the gauge and crank here over with the electric start and see what the gauge jumps too?

 

do ya think i should open up the reeds as you say and take a peak inside and see what i can see? before ripping her apart?

 

<div class="FTQUOTE"><begin quote>Originally posted by: katt68

what should i read for compression?

can i simply screw in the gauge and crank here over with the electric start and see what the gauge jumps too?</end quote></div>

Should be no less than 100lbs comp. Install the gauge and crank it over with the electric start and see what it reads. If its above 100, then pull the air box, carb and rered cage and check out the piston skirt. If either are bad, tear down down time.

 

thanks so much guys.....do ya think i can tear it down inside the quad or pull the whole motor?