That could be a big part of your problem right there. The pre-Freedom motors were designed to run on 87 octane gas. Higher octane does not give you more performance, it actually makes the gas HARDER TO IGNITE. Octane controls engine knock (detonation) which can occur for a number of reasons, but all things being equal, it usually happens when compression is too high for the given octane gas being used. Running high octane gas in an engine designed for regular unleaded can result in carbon deposits that build up in the combustion chamber, causing compression to increase, thus necessitating ever higher octane. Unless you've installed high compression pistons in your V92C, you should run some carbon cleaner through your engine and start running 87 octane. My V92C is now 8 years and 43,000 miles old and I've always run 87 in it, with the only knocking occurring when the bike was still new and the TPS was set too lean. This was corrected even before the 500 mile service and has not recurred.