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About ubercoper

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    New Jersey

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  1. ubercoper

    KTM top end advice needed

    The cylinder was cleaned with soap/water and got a solid coat of oil before the piston went in. Needle is on position 4 (2nd from the bottom), I don't remember what jets I'm running off the top of my head. I was judging the richness by the spark plug. I had run the same setting on the previous top end which lasted about 1.5 years, but that may have been too lean. The piston/rings were weisco... It's possible, but unlikely, that I could have misjudged the ring gap as well. The crank spins freely when the flywheel is turned, and the rod play is within spec as well. I am concerned that some of the metal from the cylinder has gone into the crank/bearings. I've heard mixed opinions about flushing the crankcase on 2T bikes. If the cases need to be split, I'd be at the point where it almost isn't worth spending $1000 on a bike that is worth $2500.
  2. ubercoper

    KTM top end advice needed

    I did the rebuild myself, so nobody else to blame. The top end kit was from Cooksey, so I don't think he would have steered me wrong with the piston suggestion. I didn't measure the out of round because I had the cylinder replated by powerseal before the rebuild... which sucks even more in retrospect. Piston rings were the right way up. C-clips were in the piston, and I don't specifically remember and odd noises before the end. Gas and oil were mixed. Con rod has 0 vertical play but probably 1.5mm of horizontal movement. The failure occurred a when I was at 1/2 throttle riding around Vermont a few days after I raced in a hillclimb event (street, not dirt). On my last run, I had a bit of a crash and laid the bike down. It wasn't fast or a terribly hard hit and didn't seem to have any issues for the next couple days. Break in was done with a few heat cycles and some midrange revs. I know there are many views on which way is correct, but that's the one I ended up going with. Jetting seemed to be on point, if anything it was a little rich. The previous top end that was in the bike when I purchased it lasted for a year and lots of abuse. 2 things did occur to me: 1. There is/was a slight exhaust leak by the powervalve 2. Completely forgot to mention: I installed aftermarket radiator hoses after the hill climb, maybe something happened with water pump or thermostat? EDIT!: I found this picture from before I installed the new rad hoses. This is what the cyl/piston looked like after the hillclimb and like 2 hours before it went boom.. Thanks again for the help guys
  3. ubercoper

    KTM top end advice needed

    I've been AWOL on here for a few years but I'm desperately in need some advice/ "expert" help... My 2000 KTM 300 grenaded with about 10 hours on a fresh top end. Here are the teardown pics. Piston is gonzo and the cylinder is going off to powerseal usa for repair. I'm wondering if this could be related to the horizontal play in the con rod? I may send this out to Andrew Cooksey to split cases and go deep ($$$) into a rebuild, but I'd like to save the expense if possible. Any and all advice would be appreciated. Thanks in advance! -Seb IMG_6216 by ubercooper2000, on Flickr