I am sorry, but here is were engines actually goes bad. Running it out of fuel and store for a week, corrosion will start eating on the bearing races and balls if you do not have a bearing with cceramic balls. I have done the exact same thing and i did not understand why my engine ate bearings. Not shure why but it seems that when running Byron fuels, its better to leave fuel inside the engine rather than burn it out.

Also, from my experience and many other racers here in Norway, the Byron xxnitro, 8 and 9% oil fuels, does reduce the longevity of the engine. 25/11 is the best compromise from Byrons and is a very good fuel.

As soon as the bearing starts making noises, you should stop running the engine as small metal particels eats up your piston.

Regards airfilters, i never run more than 50 minutes on an airfilter, ever. Even on clean tracks i change them frequantly. Airfilter oils used should be methanol safe. Alot of the motorcross airfilter oil is not made for this. If you stop you engine on the pipestinger, fuel blows backwards through the carb and oils is desolved. Next time you start your engine on that raceday, youre pulling dust inside your engine.


If you please could post pictureres, i like to see picturers of glowplugs used, crank and a pic of rear engine bearings. Also the exhaust side of the piston would be interesting.

Novarossi usually is very very good. The only thing i know could be something hat needs to be changed often is the front bearings. The 17011 is very very good, but the other ones gets worn out. (it does on OS, REDS and other engines too, so the quality of the standard Nova bearing is not any worse than others, it just the 17011 is alot better tahn evryting else) I use the 17011 bearing in my OS engines... When you engine starts acting up and you need to chase the tune, try and spray brakeclean between you flywheel and front bearing. if your engine stops, your front bearing is shot. I would recomend getting the BUKU front bearing cap and run this from your engine is new. I killed two OS engines from sucking dirt through the front bearing. Never erver fond out were the dust came from as there were no signs of dust inside the carthorat or airfiler neck.