Jram2088 Posted November 9, 2013 Report Share Posted November 9, 2013 (edited) So my banshee has been running like crap lately every1 kept blaming it on the carbs cause i had 34mm mikunis flat top, I ordered a set of stock carbs mikuni 26mm bike still ran like crap cleaned like 5 times still ran like crap lol, so I decided to do an engine rebuild on my bike and when I take off my head it is destroyed move on to the piston n besides the piston is missing chunks from the top a whole piece of it broke, so I have the following quest? Quest 1: what could have cost this to happen and what can i do to prevent it later on again? Quest 2: should I open up my entire engine to clean it up in case there's any loose metal in there? Quest 3: if I shave my head to make it smooth again would I have to change anything on the bike or can I keep all my stock parts for example pistons rods n everything? Please guys help me this is a 911 post You can see the broken piston Edited November 9, 2013 by Jram2088 Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted November 9, 2013 Report Share Posted November 9, 2013 That motor needs a total rebuild. I would not even put it back together without tearing the bottom end apart and replacing every seal. You'll have to check the cylinders to make sure they're salvageable. Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted November 9, 2013 Report Share Posted November 9, 2013 Yep. That needs to be torn clear down and gone through from the bottom up. Quote Link to comment Share on other sites More sharing options...
joey83 Posted November 9, 2013 Report Share Posted November 9, 2013 A little bit of investigation before you tore it down woukd have helped. But now that its down rebuild it, split cases and clean very well, new seals and gaskets, and look it over well. Check intake boots for cracks or any obvious stuff lije that. Once its rebuilt do a leakdown test!!! You obviously need new pistons and rings. How do the cylinders look? Im guessing theyre tore up too? Sent from my SCH-I500 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
troyzstang Posted November 10, 2013 Report Share Posted November 10, 2013 Not sure but looks like just clearance issues. Piston got sloppy and took a shit . Quote Link to comment Share on other sites More sharing options...
oldskool Posted November 10, 2013 Report Share Posted November 10, 2013 Take it apart, not that hard. You can download a service manual from this site if you don't have one. There is also a great bottomend rebuild thread in here somewhere Quote Link to comment Share on other sites More sharing options...
Jram2088 Posted November 10, 2013 Author Report Share Posted November 10, 2013 the cylinders to me seem to be on perfect condition just looks like the head n piston took all the damage, i already got new seals for everything and tomorrow I will go get tools to take the entire bottom end apart hopefully I don't find more bad things, I will post a picture of my piston n cylinders later on so you guys can see everything. Any reason you guys think this could have happen, would it have anything to do with the carbs ? Quote Link to comment Share on other sites More sharing options...
Trenton Tigney Posted November 10, 2013 Report Share Posted November 10, 2013 You do not need a case splitter to split them cases just saying so don't buy one Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted November 10, 2013 Report Share Posted November 10, 2013 (edited) worn pistons or cylinder caused that. Unless the cyl is within wear specks for out of round/taper, it needs to be bored. Edited November 10, 2013 by Larry's Shee Quote Link to comment Share on other sites More sharing options...
joey83 Posted November 10, 2013 Report Share Posted November 10, 2013 Check piston clearance. Cylinder diameter minus piston diameter. Sent from my SCH-I500 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
camatv Posted November 10, 2013 Report Share Posted November 10, 2013 head to piston contact damage is there.. detonation.. bad dome shape also. Quote Link to comment Share on other sites More sharing options...
joey83 Posted November 10, 2013 Report Share Posted November 10, 2013 What about the cracked skirt? Detonation? Sent from my SCH-I500 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
04_blu_shee Posted November 10, 2013 Report Share Posted November 10, 2013 I'm with Cam, first thing I thought when you described damage was detonation. Holes in piston = detonation not good Quote Link to comment Share on other sites More sharing options...
RollinRhino Posted November 10, 2013 Report Share Posted November 10, 2013 Oh boy. You are about to learn a lot about Banshees by the time it's running again. Quote Link to comment Share on other sites More sharing options...
Coupelx Posted November 10, 2013 Report Share Posted November 10, 2013 Not one person mentioned bearings. I bet they are spectacular after eating aluminum. Quote Link to comment Share on other sites More sharing options...
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