Lerea3 Posted April 11, 2016 Report Share Posted April 11, 2016 Recently did the top end on my 07, did compression test and it was around 85. Guy I bought it from must have been in the top end because the ring end gap was huge! ran fine after top end was done but noticed the left pipe was hotter then right side. All of a sudden the bike lost power and started knocking. This is what I found (pic) I'm new to the banshee world but have rebuilt many 2 strokes. Bought bike with TORS removed, idle screw kit installed, K&N open box intake, twist grip throttle, park brake removed -New rings, wrist pins, bearings and Pistons. -ring end gap within spec -cylinder bor with in spec -crank well within spec -leak down was good -cleaned carbs -sync carbs by eye Was waiting to break it in to do a compression test but that ship has sailed! Why was the left side running so much hotter? Air screws were adjusted the same. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted April 11, 2016 Report Share Posted April 11, 2016 Is it still together? Quote Link to comment Share on other sites More sharing options...
Lerea3 Posted April 11, 2016 Author Report Share Posted April 11, 2016 I tried to attach a pic but it's to big. I have the head off and it looks like there was big time detonation going on. I'll try to resize the pic Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted April 11, 2016 Report Share Posted April 11, 2016 Put head back on and leak down again Quote Link to comment Share on other sites More sharing options...
Lerea3 Posted April 11, 2016 Author Report Share Posted April 11, 2016 Jumped a head and pulled cylinder. Big end bearing is completely gone! Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted April 11, 2016 Report Share Posted April 11, 2016 Carbs cleaned? How do the jets in the melted side look? Quote Link to comment Share on other sites More sharing options...
Lerea3 Posted April 11, 2016 Author Report Share Posted April 11, 2016 Both carbs were cleaned, 280 mains stock pilots and clip in the middle. The con rod on the big end got so hot it's discolored. 1 Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted April 11, 2016 Report Share Posted April 11, 2016 Jumped a head and pulled cylinder. Big end bearing is completely gone!Well, I guess we'll never know. Quote Link to comment Share on other sites More sharing options...
salmon_slayer06 Posted April 12, 2016 Report Share Posted April 12, 2016 Many have been down this road. A good leak down test is a must. Make sure you check again before you put the pipe and carbs on. 1 Quote Link to comment Share on other sites More sharing options...
guns4children Posted April 12, 2016 Report Share Posted April 12, 2016 Never did a leak down. My 421 serv has been running 5 years Quote Link to comment Share on other sites More sharing options...
r_gillies Posted April 12, 2016 Report Share Posted April 12, 2016 What does a failed bearing have to do with air leak? Pressure test won't prevent mechanical failure. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
bigweav81 Posted April 12, 2016 Report Share Posted April 12, 2016 That bearing could've have taken a shit from an air leak........creating a lean condition. A leak down test could've revealed the reason why, and where. sent from yo mammy house. Quote Link to comment Share on other sites More sharing options...
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