just did a compression check on my 96 sportsman 400 2 stroke i did this because im having alot of smoke coming out of the exhaust at w.o.t the machine runs great good power i stillneed to check for oil pump adjustment.

back to the compression? the check came up with 123 p.s.i.....is that good,alright,or getting bad? should i rebuild the top end? just trying to rule out this as the reason for the smokey issue? oh yeah i did the compression check with the engine cold.

thanks

hoyt

 

That's good comp.
you should be good to go!!!.......You need around 100 P.S.I. to at least run!!!!
Check you flow !!...........Caper..........

 

the smoke could be from the oil your using.

 

Line up the marks on the oil pump at idle position, that's how the 250's are done. Check your air filter, if it can't get air it'll triy and draw in whatever it can get. Compression should be fine. Check the plug, for 2.50 heck replace it.

 

im running polaris synthetic gold oil i did put a new plug in it and ran thru the field once when i pulled the plug for the compression check it had alot of oil ( it was wet) so its definatly running rich or getting to much oil i replaced the filters last year and used it very little filters look good. i just had the oil pump rebuilt at the dealer you would think they would of had it adjusted properly.

tthanks hoyt

 

the compression is ok. the oil your using is good as well. i would say check the oil pump setting as your getting too much. also make saure the main jet is correct that your getting the correct amount of gas. you have good idle to top throttle response right?

 

im trying to figure the oil pump out now, its idles fine in low it will stand the front end up so the response is good any idea what main jet is suppose to be in this im gonna pull the carb and see what is in there.

 

oil pump seems to be in adjusted right, i did a search and found old posts that some of these 2 strokes would smoke so guys changed to k n,uni filters helped get more air so they wouldnt run as rich . the machine only fouled one plug and that happened after the oil pump spring broke and was stuck open.

any thoughts on getting rid of the paper filter for a better aftermarket?

 

main jet i beleave is a 210. some do put in a k&n or uni and have good luck w/ them. just make sure you keep them oiled to prevent dirt from ging in the carb and also not to oil them too much as it will alsdo make it run ricvk w/ too much. hows the air screw set. dont have it too far in shutting down the air? basicly if its not fouling plugs and has all kinds of power and you can live w/ it smoking, run it . you may be able to drop 1 jet size if its running too rich but always keep an eye on the plug for it being too lean.

 

ok i will check the air srew on the carb and probably order a k and n filter for it.

thanks for the help

hoyt