03banshee20 Posted May 24, 2011 Report Share Posted May 24, 2011 i bought my banshee last year it had new pistons in it and i looked up in the exhaust port and saw the right side of the head was pitted but i knew the piston wasnt. so i tore it apartt last night because i was going to get my head shaved but noticed this. what happened? and should i run it or what. also this is the cylinder with 115 and the other has 120 it has ssts vforce 3 +4 timing and rejetted. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted May 24, 2011 Report Share Posted May 24, 2011 A good thing to do b4 you tear anything down is a pressure test on the motor,this will let you know if the pitting happened due to an air leak.After you have established no air leak its time to start looking at rod bearings and big end thrust washers on crank Quote Link to comment Share on other sites More sharing options...
bansheeseat$$ Posted May 25, 2011 Report Share Posted May 25, 2011 Check the right side crank bearing,There is a little ball on that bearing that is supossed to go into the case inbetween the case halves and if it wasn't installed in the correct position it will come out of the bearing and end up in the top end and do exactly what you are describing. Quote Link to comment Share on other sites More sharing options...
03banshee20 Posted May 25, 2011 Author Report Share Posted May 25, 2011 Check the right side crank bearing,There is a little ball on that bearing that is supossed to go into the case inbetween the case halves and if it wasn't installed in the correct position it will come out of the bearing and end up in the top end and do exactly what you are describing. okay can i do that without splitting the cases or just take the jug off and tell Quote Link to comment Share on other sites More sharing options...
bansheeseat$$ Posted May 26, 2011 Report Share Posted May 26, 2011 You will have to split the case.. Quote Link to comment Share on other sites More sharing options...
Strm Trpr Posted May 26, 2011 Report Share Posted May 26, 2011 Post a picture. It could say more than you could in 1000 words. Pitting on piston crowns and head domes is also a sign of detonation or knock. I run a 65lb/min Turbocharged 97 Mitsu Eclipse GSX. The spare head I had built had its fair share of detonation pitting from knock. Could be an air leak like the 2nd guy said. This would make that cylinder run lean. Running lean would increase combustion temps, which would increase the chance of pre-ignition of your air/fuel mixture, which then leads to detonation. You say you're running +4 degrees timing advance. What fuel are you running? What does the questionable cylinder's sparkplug look like compared to the other? If the plug has signs of fuzzy gray material on it, that is vaporized aluminum. Just a guess guys, feel free to call bullsh!t... Quote Link to comment Share on other sites More sharing options...
Strm Trpr Posted May 27, 2011 Report Share Posted May 27, 2011 Yo... Any word on this? Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted July 30, 2011 Report Share Posted July 30, 2011 (edited) I would've like to know what cause his engine to do that. Mines done the samething about 3weeks ago. I tore the top end down & the piston crown & domes was pitted. Rings were stuck to the piston but the cylinders looked fine. The inner crank thrust washer was completely shattered into pieces, but the crank turns smooth. The connecting rod has to much play in it so im just going to send Kevin this other stock crank I have & see what he thinks. Now that I think back what could have cause this, my first sign was when I was riding it & the spark plug backed out. I thought that maybe came from I didnt tighten it good enough. I tighten it pretty good this time & it never backed out again. Last time I checked compression I had 21cc domes in @ 115 psi. But I installed 18cc domes to bump up the compression some more. My set-up at the time it broke down was 18cc domes, +6 timing, 100LL avgas, crank was trued & weld, SB IF Shearers, jetting @ sea level 52 pilots, CEG mid clip postion, 160 mains , temp 90+. I will post pics of what mines look like before I send any parts to Kevin. OOooo dont mean to thread jack...... Edited July 30, 2011 by 252wheelieking Quote Link to comment Share on other sites More sharing options...
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