I've had 2 rounds and 1 oval. I believe they where all early. On the two rounds the, the rubber is in good shape, but they where ported to match the intake and they failed where they where bonded to the aluminum on the bottom of the intake tract. The oval was previously own by the same person who sold Wayne his motor and I ran it one weekend and it was completely rotten a few weeks later similar to what Wayne's saying. I was wondering if it could be the castor oil, because the first two years I purged with synthetic oil because it was easy to use what I ran in my other bikes. But I haven't got to ride on gas bike that much so I started using castor on the purges and that's when I first had failures. I thought maybe the castor could have something in it that is slowly breaking down the polyurethane.
