smitt88 Posted December 30, 2008 Report Share Posted December 30, 2008 i believe i spun the barring in my crank. im guessing on only one side, because i get great compression from one cylinder and the other is crap. i have no metal shavings in my motor. does this sound like more than a crank barring ? how much you think its gonna cost for a repair? thanks alot Quote Link to comment Share on other sites More sharing options...
spurdy Posted December 30, 2008 Report Share Posted December 30, 2008 i believe i spun the barring in my crank. im guessing on only one side, because i get great compression from one cylinder and the other is crap. i have no metal shavings in my motor. does this sound like more than a crank barring ? how much you think its gonna cost for a repair? thanks alot Sounds more like rings or cylinder to me. Bore and hone and new pistons is more likely. SP Quote Link to comment Share on other sites More sharing options...
Wildcard2 Posted December 30, 2008 Report Share Posted December 30, 2008 i believe i spun the barring in my crank. im guessing on only one side, because i get great compression from one cylinder and the other is crap. i have no metal shavings in my motor. does this sound like more than a crank barring ? how much you think its gonna cost for a repair? thanks alot Sounds like an issue with your piston/rings or your reeds, not a bearing. What has lead you to believe it is your crank? My advice is to remove the carbs and have a look at the reeds and then the head and examine the piston and bore to determine the cause of your compression issues. Quote Link to comment Share on other sites More sharing options...
smitt88 Posted December 30, 2008 Author Report Share Posted December 30, 2008 i checked the pistons and they're fine and my rings are worn but nothing to the extent that it wont run . Quote Link to comment Share on other sites More sharing options...
smitt88 Posted December 30, 2008 Author Report Share Posted December 30, 2008 i can physically wiggle the crank arm itself. im just going off of what i was told from a relative. he knows his stuff when it comes to two strokes but like im doing now. its always good to get a second view. Quote Link to comment Share on other sites More sharing options...
spurdy Posted December 30, 2008 Report Share Posted December 30, 2008 (edited) i checked the pistons and they're fine and my rings are worn but nothing to the extent that it wont run . Connecting rods will have a little play. The lateral tolerance is called out in the Bible (Clymer manual). How would a bearing cause low compression. Compression is obtained by pressurizing the volume between the top of the piston and the dome above the exhaust roof. Intake and transfer ports are closed as well so the reeds are not in question. The top of the piston doesn't provide an adequate seal, that is what the rings are for. The only other place to leak pressure is through a hole in the piston, the spark plug thread or the head seal (o-ring or gasket). Crank bearings play no part in this. SP Edited December 30, 2008 by spurdy Quote Link to comment Share on other sites More sharing options...
smitt88 Posted December 30, 2008 Author Report Share Posted December 30, 2008 well this is what i did to discover my lack of compression. i pulled out both spark plugs then placed my finger tip over the spark plug hole. i then had a friend slowly turn the kick start. the left side had perfect compression (air comming through the spark hole) and then the right had barely anything comming out. Quote Link to comment Share on other sites More sharing options...
spurdy Posted December 30, 2008 Report Share Posted December 30, 2008 well this is what i did to discover my lack of compression. i pulled out both spark plugs then placed my finger tip over the spark plug hole. i then had a friend slowly turn the kick start. the left side had perfect compression (air comming through the spark hole) and then the right had barely anything comming out. And after this you took it apart to find the rings slightly worn but not bad enough to cause compression loss and the lateral play in the connecting rods? SP Quote Link to comment Share on other sites More sharing options...
smitt88 Posted December 30, 2008 Author Report Share Posted December 30, 2008 i never fully pulled each piston, i was going off a brief visual . im hoping its as simple as new rings or new pistons, but i have a feeling its gonna be more than what im thinking. Quote Link to comment Share on other sites More sharing options...
spurdy Posted December 30, 2008 Report Share Posted December 30, 2008 i never fully pulled each piston, i was going off a brief visual . im hoping its as simple as new rings or new pistons, but i have a feeling its gonna be more than what im thinking. Don't have to pull the pistons. But you do have to pull the jugs. You will have to pull the pistons to get an accurate measurement on the large end play of the rod. SP Quote Link to comment Share on other sites More sharing options...
firebanshee Posted December 30, 2008 Report Share Posted December 30, 2008 Just yank the head off real quick it only takes a minute, and then go from there. If you have that low of compression you will see your problem pretty fast. Quote Link to comment Share on other sites More sharing options...
smitt88 Posted December 30, 2008 Author Report Share Posted December 30, 2008 thanks for the help guys. im new to this forum so im kinda fishing for ideas. i just took my bike to the shop and the mechanic said it does sound like a beat crank. i told him since he has the motor apart he might as well replace the cranks, barrings, pistons, and seals. im going all aftermarket. any ideas on what parts to buy? i wanna keep it all under say $1200 Quote Link to comment Share on other sites More sharing options...
spurdy Posted December 31, 2008 Report Share Posted December 31, 2008 thanks for the help guys. im new to this forum so im kinda fishing for ideas. i just took my bike to the shop and the mechanic said it does sound like a beat crank. i told him since he has the motor apart he might as well replace the cranks, barrings, pistons, and seals. im going all aftermarket. any ideas on what parts to buy? i wanna keep it all under say $1200 If your gonna have a shop do it you better get your fat wallet out! Best bet would be to buy a Clymers manual and do it yourself. It will save you a boat load of cash and you likely learn a thing or two along the way. Most guys on here do their own work (aside from porting cylinders and some do that also). There isn't much to these 2 stroke motors, even the cases are easy to work on. You would likely have some questions but most everyone here that comes up with issues finds the answers through posts and PMs. Git er done! SP Quote Link to comment Share on other sites More sharing options...
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