How often should I change my Piston Ring WR250Z

[pistons]

Hi guys I have a WR250Z 2 stroke, I belive they use a similar engine to the YZ.
The engine has had a full rebuild although I cannot be sure when although the guy I brought it from said that it would be due for a ring change in 10 hours, I have used it for about 4hrs. So another 6 to go.
But after I have changed the ring how long would I be looking at until the next ring change 15 hours?
The bike doesant get ridden hard just trails ect.
Thanks
Andy

 

[BSWIFT]

If you are a pro level racer, change the rings every 10-15 hours. On the other hand, if you are an average or even fast racer, you should get 2-3 times that many hours. Let the engine tell you when to change.

 

[pistons]

I would of put myself in the average bracket, When you say let the engine tell me when to change what should I look out for?
I was thinking along the compression side of things and in that case When the band kicks in the front wheel will lift up in the first three gears no problems and also kicking over it takes all of my body weight to turn the engine over. So that tells me that theirs lots of compression.
But what I dont want is to take too long inbetween changes and the ring fail and wreck the engine. Thats what I was unsure of will the ring just ware until thiers a noticable loss in compression?
Thanks
Alot for your help.
Andy

 

[BSWIFT]

Although it may take some physical distortion of your head and neck, you can always pull the exhaust and look inside the cylinder at any time to check the condition of the piston, rings, and cylinder. This is really just a short cut to pulling the head and cylider though. If your bike becomes harder to start but kicks over easier you are likely ready for a new top end.
FWIW, pulling the head to check the cylinder only costs you time and possibly a gasket. If you pull the cylinder, you'll need to replace rings as well. Too me, if you go that far, you should just do the entire top end. Just my $.02.

 

[pistons]

Ok basically what your saying is that its not worth replacing the ring by its self like I was advised. So basically it would be best to wait until the topend shows signs of ware as far as compression is concerned and rebuild the whole topend.
I wonder why the guy would of advised me to change the ring by its self?
Thanks Andy

 

[arnego2]

compression only tells you how good your ring seal is. Pistons have a life span. They do shatter if used too long. On a 250 about 50 hours. I change mine at 40. Forged pistons 10 hours longer.

 

[BSWIFT]

Here is another way of looking at this. If you pull the head & cylinder to inspect the piston, you replace the ring. You can do a less invassive inspectin by pulling the head and removing the exhaust but this is not a complete picture. Tearing down to "just" replace the ring is not really the reason, tearing down to "inspect" the piston is the reason, the ring is just a casualty of the inspection. The advise you received was just off point.
Properly jetting, being consistant on fuel and oil mixture will prolong the life of your piston, ring, and cylinder but it will not last forever. How you ride along with the maintenance you perform will be the determining factor. My suggestion of letting the engine tell you does not mean you wait until catesrophic failure or compression tests it simply means let your "butt dyno" tell you when the power is dropping off.

 

[pistons]

Thanks for your comments guys, im makes more sense now.
Thanks
Andy

 

[Caydenner]

mainly i change my pistons at after every 7 hours and that keeps it fit to ride as i am regular rider so it needs very much quick replacements