My question is how long a piston should last in a 250R with a Pro-X piston .030 over ??? I have been told 60-70 riding hours under good conditions, meaning proper air filter cleaning and running the right oil in the fuel. I run Power Mist. Any help would be appreciated.

 

This might help and it might not

I have an 81 ATC 250R and it has seen more than 60 hours of riding on the stock piston. This machine has been used and abused ie... trying to drag a 1000lb elk with it didn't work too well. I've had it since 84 and it still will beat my 83 250R with pipes and a K&N in a drag. All I can say is if you take care of it and clean the air filter use good oil the piston can last forever.

 

I never have owned a 2 stroke quad or ATC, but with my CR's I would easly get a year out of a ring and 2 years out of a pistion when useing amsoil. The smaller the engine the more wear, so my CR500R may be not a good example. It really depends on how it is jetted as a friend runs HP-2 at 50:1 and lean jetting he eats a ring monthly and a pistion every 3 months.

 

I have a friend that has a 88 250R that he bought new. He raced it for a few years in Super Senior Class out here for a few years, now he just rides with the rest of the group. He swears that it has NEVER had a top-end done on it! That means over 12 years on a original piston. Of course, you can hear it slapping around a bit. He's just too lazy to put a wrench on it!

 

MacDizzy the internet guru of the 250R changes his every 50 hours---He hillclimbs and drag races his in the dunes though. I ride mostly in the woods and rarely push it over 8000rpm. I run Klotz R50 at 32/1 ratio(exactly what many XC racers run) and redo the topend every 100 hours(to keep down slap) as indicated by my Tiny Tach. A riding pal of mine who runs a bone stock Suzuki Quadracer 250, is STILL on his original piston(1992), however he RE-RINGS it each year. What I'm trying to say is if you keep your intake air clean and the piston well lubed you can extend your engine's lifespan. I feel that two strokes(250cc and up) should, at MINUMUM, have their topends redone every year. The metal stresses that the piston receives from the repeated heat cycles cannot be overlooked. It will ultimately be up to you and your riding style and wallet as to how often to rebuild.