gjone5 Posted March 8, 2013 Report Share Posted March 8, 2013 I just got my first Banshee last December. It is a year 2000. The guy I bought it from spoke little to no English. So I don't know if the topend has ever been rebuilt. It was riding great until a week ago. Now it has lost a lot of power. So I checked the reeds, the carbs, removed the TORS, replaced the plugs... and still has a loss in power. So I checked the compression and I got 96 on the left and 108 on the right. Seems how I am new with the Banshee, I was just wondering what the compression should be? And when is it a good time to rebuild the topend? Quote Link to comment Share on other sites More sharing options...
Banshee SE Posted March 8, 2013 Report Share Posted March 8, 2013 definitely your bike will need a top end rebuilt, with 12psi of difference I could says one piston ring is going bad very soon Quote Link to comment Share on other sites More sharing options...
gjone5 Posted March 8, 2013 Author Report Share Posted March 8, 2013 Would this low of compression create a loss in the powerband as well? Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted March 8, 2013 Report Share Posted March 8, 2013 125 IS STOCK AND YEA Quote Link to comment Share on other sites More sharing options...
Finch Posted March 8, 2013 Report Share Posted March 8, 2013 125 IS STOCK AND YEA Depends on your elevation. But this guy is in cali so im sure close to sea level Quote Link to comment Share on other sites More sharing options...
bluebanshee98 Posted March 8, 2013 Report Share Posted March 8, 2013 rebuild the top end and do a leak down test to make sure you dont have any air leaks! Quote Link to comment Share on other sites More sharing options...
icytea132 Posted March 8, 2013 Report Share Posted March 8, 2013 I had 115 per cylinder after my rebuild, beat running motor ive had so for, I truly don't know what the rebuild level would/could be but with that difference, your putting stress on half of the motor and half of your bearings witch will cause more trouble than just for your pistons. I would test a few things and find your problem on why you are getting lower psi in one cylinder pm me for tips or tricks, gladly help! Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted March 8, 2013 Report Share Posted March 8, 2013 you're top end is in need of a bore/hone and new pistons. You should be kicking somewhere around 125 psi (unless your running a milled head or a noss style head). You should also have NO MORE than 10% of a difference in compression between your cylinders.......and TRUTHFULLY it should be closer to no more than 5% between cylinders. 2strokes are MEANT to have the top ends rebuilt.....it will roughly cost you about $300-$400 depending where you go to get the top end rebuilt. IF you don't get it taken care of and continue on the already hurting motor you can do more damage that will cost you more money in the long run. my friend just did this.....kept pushing his luck and was in the 90's for psi and suddenly he dropped on cylinder all together....0 psi. pulled it down and he snagged a ring and took a chunk out of his exhaust port........wound up with aftermarket cylinders now.....he spent almost $2000 now to get running again when he could have spent $300 and been back up.....of course he did go with a bigger motor but he would have still been over $1000 Quote Link to comment Share on other sites More sharing options...
gjone5 Posted March 9, 2013 Author Report Share Posted March 9, 2013 So by the looks of it, I will be rebuilding the topend. I will tear it down tonight or this weekend. I would have ordered the parts already, but I need to be sure what size pistons to order. I will probably buy new reeds while I'm at it. Thanks for all the info and suggestions. I will take pics of it all and post them also. Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted March 9, 2013 Report Share Posted March 9, 2013 u need to get the cylinders checked berof u get the pistons to see the size easy to bu the wrong ones the piston tsould have number on top the last four are the piston size hit them with a wir wheel to see wat they are Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted March 9, 2013 Report Share Posted March 9, 2013 i had 60 psi on mine my pistons were worn from dirt make sure u bring the pistons and the jugs to get measured to see if they need a bore up Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted March 10, 2013 Report Share Posted March 10, 2013 correct........YOU should not be ordering your pistons. Let the machine shop do that. They will mic your cylinders and tell if you need to be bored/honed, and then they will order the correct pistons......then a GOOD machine shop will WAIT until they receive the pistons to bore your cylinders. This is because no matter what, pistons are always JUST a cunt hair different in size and any good machine shop will want to make sure the tolerances are absolutely correct. This is why sometimes you will get brand new pistons back and the machine shop has marked them LEFT and RIGHT.......its because they measured them first THEN bored them to exact size based on the piston to go into that jug. Quote Link to comment Share on other sites More sharing options...
gjone5 Posted March 10, 2013 Author Report Share Posted March 10, 2013 Quote Link to comment Share on other sites More sharing options...
gjone5 Posted March 10, 2013 Author Report Share Posted March 10, 2013 Well, so the pistons and cylinders didn't look that bad. But I am still going to have it bored and start fresh. Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted March 11, 2013 Report Share Posted March 11, 2013 they look a little worn Quote Link to comment Share on other sites More sharing options...
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