Was racing sunday and my stock pipe blew out at the seam just in the second 90 degree bend. Still not sure why. Bike was ripping though. Running 92 octane Chevron and Motorex Synthetic 2-stroke at 40:1, stock jetting. Put the SST on and the bike began to ping on the longer straits and uphills. I just let it ping and pinned it. Motor held together. But I am concerned.
Whats the deal? It wasn't pinging with the stock exhaust pipe (or at least I couldn't hear it) Can an aftermarket pipe make a motor detonate? Should I switch to race gas? I checked my top end out before the race, and it looked really good. No scratches or scrapes on intake or exhaust. I don't think it was pinging before.
Called FMF and they said they never heard of that before. The guy suggested race gas. I thought race gas was needed with high compression race engines, not exhaust pipes...
Anyone run into this before?