YamaBomba86 Posted March 31, 2010 Hey folks I have an 81 yz 125 that intermittantly runs poorly up to the powerband once it gets there it pulls great, also sometimes it idles up real high all on its own. I am fairly new to 2 stroke engines and any input would be much appreciated, thanks. Share this post Link to post Share on other sites
jsantapau Posted March 31, 2010 1st clean your carburator and pay particular attention to the pilot jet/circuit. second look for an air leak, with it being an 81 the carb boot and main bearing seals being dry rotted/cracked would not surprise me at all. Share this post Link to post Share on other sites
YamaBomba86 Posted April 1, 2010 I have gone through the carb and it seems to be in order,the boot is cracked on the outside but solid on the inside. Are the main bearings part of the intake system? like i said im new to 2 strokes lol Share this post Link to post Share on other sites
jsantapau Posted April 1, 2010 not really in a kinda sorta way but yeah the seals are in a kinda way. I suggest you search ,google ,ask jeeves on how a two stroke works and maybe you will kinda understand what I am kinda talking about Share this post Link to post Share on other sites
YamaBomba86 Posted April 2, 2010 oh ok i see the intake charge is kinda routed through the crank case, im pretty sure its just a dirty carb,got a build kit runs good thanks for the help man. Share this post Link to post Share on other sites
