Dunerider Posted February 28, 2011 Report Share Posted February 28, 2011 so i pulled my motor apart to day to do a rebuild and found my left piston had a crator in the middle of if and the pistons are really dirty. i also had a head stud that wouldn't go in all the way so when i had the head off i screwed in the stud and the whole cylinder sleeve moved inside the jug. it has an aftermarked 400 sleeve in it. my question in does anyone know why it has a crator in the middle of the piston and if the sleeve should move at all. i am sure the sleeve shouldn't but thought i would get your guys opions. i run 35 to 1 with royal purple synthetic two stroke oil i was running 32 to 1 until the last maybe 6 rides. http://s1231.photobucket.com/albums/ee510/wheeinman/ Quote Link to comment Share on other sites More sharing options...
gstaten24 Posted February 28, 2011 Report Share Posted February 28, 2011 Not sure about the sleeve but I know my piston did that because I was running too lean, could have something to do with it, I'm not an expert tho I'm sure somebody else will chime in here soon Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted February 28, 2011 Report Share Posted February 28, 2011 The pistons being dirty is a normal thing for a 2-stroke motor.....its just carbon build up from the oil that your burning in your fuel....nothing to worry about with that. The reason you have a hole forming in the middle of on of your pistons is because your carbs are not tuned correctly....your running way lean and your motor is about to meltdown.....sorry for the bad news...but it looks like you gotta do a top end! Quote Link to comment Share on other sites More sharing options...
Dunerider Posted February 28, 2011 Author Report Share Posted February 28, 2011 I pulled it a part to do a rebuild anyways. I was just wondering y it was that way. When I pull the plugs out they are alway a nice brown never white at all Quote Link to comment Share on other sites More sharing options...
midlifecrisis Posted February 28, 2011 Report Share Posted February 28, 2011 The hole is a detonation issue cause by an air leak or another type of lean condition caused by a carb being lean. Questions that beg to be asked, where are you, elevation, mods etc, carb sizes...................? As far as your sleeve, I think you know the answer for that one. That sleeve has to be pressed in under extreme pressure while cooling it with liquid nitrogen, if it moves with you wiggle a loose bolt, there might be an answer to your questions right there. Quote Link to comment Share on other sites More sharing options...
Coupelx Posted February 28, 2011 Report Share Posted February 28, 2011 as was mentioned the sleeves are frozen and then pressed into the jugs which are warmed in an oven. whoever sleeved the jugs messed up from what you are describing. Quote Link to comment Share on other sites More sharing options...
Dunerider Posted March 1, 2011 Author Report Share Posted March 1, 2011 Yeah I knew that they sleeves were cooled then stuck in the oven. I am looking for a set of used cylinders I posted a wanted thread before this one just thought I would ask. I am at about 3000 ft it's bored .020 over with a pro design cool head 19cc domes was about 175 psi a cylinder stock carbs pro flow filter adapter in stock air box wiesco stock stroke crank motion pro tors eliminator kit old school fmf pipes not sure on jetting haven't messed with since rebuild 4 years ago. The squish was at .035 and one cylinders compression had dropped to 155 that was why I tore it apart was fix the squish gap and rebuild Quote Link to comment Share on other sites More sharing options...
Paulie B Posted March 5, 2011 Report Share Posted March 5, 2011 I'd be a lil irate at whoever sleeved that jug. You need to contact them and get a refund + a new jug. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.