joey83 Posted September 17, 2012 Report Posted September 17, 2012 http://i491.photobucket.com/albums/rr277/joey_boatner/2012-09-16173114.jpg http://i491.photobucket.com/albums/rr277/joey_boatner/2012-09-16175303.jpg http://i491.photobucket.com/albums/rr277/joey_boatner/2012-09-16172028.jpg Well I took the banshee out today to double check everything for the bhq LS ride but didnt make it out of my shop. I just got the jetting pretty good and overheating issues fixed. When I fired it up it wouldnt idle and was a total dog on the bottom end. Long story short the right side had 30 psi compression so I pulled it down and found the rings broken piston broken and cylinder sleeve cracked. I just had it apart and put the used top end from NYUK on it trying to buy time til winter(cylinders,crank,pistons and rings) I know the rings were in right when I slid the cylinders down because I checked a bazillion times. Any ideas what happened???? Is my vision getting bad? Or did something come in or something on cyl wall break rings and then let them spin? I dont know so any ideas or things to check would be appreciated! I gotta get this thing fixed before the little sahara ride. Thanks-- Quote
joey83 Posted September 17, 2012 Author Report Posted September 17, 2012 1st pic of cyl walls I circled the damage. 2nd pic is intake side of piston 3rd pic exhaust side. I had 130 psi compression on both sides after "break in" and left hole is still at 130. Pretty stock bike fmf pipes and silencers k&n with pro flo adapter +4 timing 280 mains and 27.5 pilots oem carbs tors delete 800' elevation stoke stroke and all virgin stock bore no porting cylinders Maybe 3 hours on motor since assembly Quote
vulvafan537240 Posted September 17, 2012 Report Posted September 17, 2012 did you do a leakdown test before running it? Quote
BigRed350x Posted September 17, 2012 Report Posted September 17, 2012 What was your ring end gap? What was your piston to cylinder-wall clearance? Cast or forged pistons? Were the port windows chamfered? Did you do any piston prep before installing the top end? New or used wristpin bearings? The black on the exhaust side of the piston below the rings tells me you didnt check some of the above. Those also look like cast pistons. Stock or namura junk... -jared Quote
joey83 Posted September 17, 2012 Author Report Posted September 17, 2012 Yes they're stock pistons. I didnt do any of that. Pulled that top end from a good running bike and slapped it on mine trying to buy time until this winter. The only thing I did was clean stuff up. You think the black happened before the ring broke? Quote
joey83 Posted September 18, 2012 Author Report Posted September 18, 2012 I did clean all the carbon from pistons and rings and cylinders. I made sure to put the pistons back in the cylunders they came out of and put the rings back on pistons in same grooves etc. I thought ring broke and made that hot spot. Do you think the hot spot happened because of a ring gap being too tight then th rings broke? any help? Quote
BigRed350x Posted September 18, 2012 Report Posted September 18, 2012 I didnt do any of that. Pulled that top end from a good running bike and slapped it on mine trying to buy time until this winter. You gave yourself the answer to what happened... Take the time and buy the tools needed to check, measure, and build it correctly before you slap the next one together and you will save yourself more money down the road. A good investment up front will save you hundreds and hundreds down the road. -Jared Quote
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