piston rings

[thenutt]

hi all, quite a newbie to the 2 stroke's
just wanted to know how often do i need to change my piston rings ETC, is there a millage or do i wait till they go, the bike is a 2002 model and has covered only 2500 miles, the compression has not dropped, i have only changed the sparkplug once in the last 6 months, as the bike as always started within the first 3 kicks,

 

[iancp5]

Most people change once a year to be sure but the bigger the bike the less they need it. The 300's need it least but it really depends on how you are using them as well as how many hours on the engine. Higher rpms wear more. If you don't use it much and it's mostly low revs they'd last a long time in a 300. A 125 is a different story because you have to rev the nuts off to get it to move and they rev higher as well. Some only have 1 ring too.

But you don't want to wait until it fails! Sudden drop in compression or rattle means change it immediately or at least diagnose what's wrong. If a piston fails in use it could cause a lot of damage - read expense.

This may not help but there is no easy answer on a dirtbike hence many do them once a year and guys racing hard on 125's probably more often.

 

[thenutt]

Most people change once a year to be sure but the bigger the bike the less they need it. The 300's need it least but it really depends on how you are using them as well as how many hours on the engine. Higher rpms wear more. If you don't use it much and it's mostly low revs they'd last a long time in a 300. A 125 is a different story because you have to rev the nuts off to get it to move and they rev higher as well. Some only have 1 ring too.

But you don't want to wait until it fails! Sudden drop in compression or rattle means change it immediately or at least diagnose what's wrong. If a piston fails in use it could cause a lot of damage - read expense.

This may not help but there is no easy answer on a dirtbike hence many do them once a year and guys racing hard on 125's probably more often.

ok thanks for your help, not sure about hours, but milleage is now 2600

 

[MattR]

2600 miles @ 15 mph average speed would give you about 173 hours. Actual engine hours may be different but this would give you a ballpark number to relate with. A lot of folks replace the topend yearly for peace of mind. Others put new rings in twice before swapping out the piston. For me, I would replace the topend between 175-200 hour range (2500-3000 miles). This is ever couple years at my riding pace. Even though it runs fine, the piston can fatigue and crack the skirt... then you have bigger issues.