KTMGene390
New Member
same with me but no pcv yet. just 100% stock on the engine side. i do not push it as hard as the other riders though. once the season is over, i do plan on getting the exhaust and pcv, do a full dyno and hopefully keep the bike running richer to avoid any future issues.
When I first installed a wideband o2 setup I ran the stock map as a base line to built a custom map (I have intake & exhaust mods), and before applying changes my A/F ratio was over 15:1!! Stock these bikes are lean at 14.5:1+! The stock narrow band o2 sensor will try to always compensate to keep your bike running lean without a PCV or equivalent. Also, keep in mind if you travel to different altitudes this affects your A/F as well. This is why a wideband setup is best because instead of having to rely on a dyno at each location you can make changes on the fly. If you just have a single map that is perfect at one location, i.e. sea level and go up in altitude your bike will run richer, but if you have the same air fuel ratio setup at say 6000 feet and go down to sea level your bike will run leaner.
As far as head gaskets blowing goes too much heat can warp the cylinder head and some are probably not machined smooth enough from the factory. The stock cooling system is really only adequate with light engine mods, high pressure radiator cap & Engine Ice/Water Wetter etc. Temperature and how hard you ride your bike among forementioned variables will determine if your cooling system is sufficient. If your fan is coming on and staying on multiple laps that is a warning sign, most race bikes do not even have a fan or thermostat.