polaris 250 engine rebuild

61brown61 · #1 (**permalink**) 12-14-2010, 09:45 PM

i just rebuilt the top end on this atv...new piston and rings and a used cylinder all stock ( not sure on cylinder but thats what the guy said) but anyways its seems like im not getting good compression.....it has spark and fuel but wont start....seems like it turns over really easy but it also has enough compression to blow out the exhaust.......the pistion went in semi easy ....didnt really have to compress the rings but it seemed tight when i pulled the rope without the head on.......
any ideas

mechanike · #2 (**permalink**) 12-17-2010, 03:38 PM

get a compression guage $15 at autozone.if you can fit a feeler guage bigger than .005 its an overbore or wore.

**Bruce!** · #3 (**permalink**) 12-17-2010, 08:55 PM

Welcome to the board!

jdereu · #4 (**permalink**) 01-03-2011, 04:46 PM

agree with the compression text but if its coming out of the exhaust you should be fine. play with the card fuel line or even shoot it with some starting fluid

61brown61 · #5 (**permalink**) 02-08-2011, 01:51 PM

it still wont start...put a differnt jug on and it has 100psi compression....im thinking its a spark/carb issue...i can crank and crank and crank it and it fires like once every 5 mins with starting fluid but when i pull the plug it sparks good.....any ideas replaced coil under the hood by oil jug...it didnt have one...and new plug