125-200cc Should I put new piston and rings in cr144 with 40-45 hours on last top end.

I am not sure if bike need new top end I took compression test after putting new top end this spring and it was 157 psi now after 40-45 hours is 155 psi. I took pipe off and looking at piston and cylinder through exhaust looked great no black under ring. I only raced mx with bike so it was run as hard as a c class rider could but not like a pro rider would abuse it. This bike will be my back up bike and in the race series I race in they have 125-144 2 stroke class I might also race with it but no more than 10-15 hours use next year if my tc 250 runs all year like I hope. Bike has about 140 hours total and 90 hours with 144 kit on it. Thanks for any input

That's is not even 3% loss and with no color under the top ring I wouldn't touch it.

no skirt breakage concerns??

If the skirt is worn enough to break not only should you be able to see some scuffing on the skirt through to exhaust port but the rings will not seal due to a rocking piston and there will be discoloration below the rings. I have heard of rare cases where the skirt only severely wore on the reed side of the skirt but the problem was found when looking for a piston noise. Under normal circumstances rings will not outlast a piston so the time to inspect the piston is when you're replacing the rings. Same thing applies to the bore although you can peek at the bore through the exhaust port or if you have access to a borescope http://www.google.com/products/cata...=X&ei=o9W_Tpy8H4mWtwfY-O3kBg&ved=0CK8BEPICMAQ

The stock rings are like $12 so I would do those and just inspect while inside.

I'm with lankydoug. If you are going to lose sleep over it, then by all means. But IMHO that is less than 2% of the range of the tester - which unless it is a scientific class instrument is probably lucky to be within 5% accuracy. If it was my bike I would be stoked that it still read that close to the original reading. J

Here is what I would do. It is so easy to pull the top end off the Husky small bores, pull your top end and inspect your parts. Place your ring in your cylinder ~1/2" below the top and measure the end gap. If it is less than .017" and the edges aren't sharp re-install it and run it for another year. When you feel the outside edges of the ring you should feel a bevel and not a sharp edge. Your current ring and piston have worn into your current bore making a nice seal and fit. Don't interupt that unless you need to. Your compression for statistical analysis hasn't changed. If you find nicks or wear problems in your bore or on your piston/ring you might want to just make the change but not unless there is a problem you can actually feel with a finger nail. Often you will see virtical marking in your cylinder but often this isn't an actual sign of abnormal wear but areas where the ring is oscilating due to running across the ports and may be completely benign or even a sign of lack of contact. JMO

Ok Wallybean I will take it apart to check. I still have my stock 125 cylinder would it be better to just change it over to 144 sound like you have it figured out.

Do Huskies come with a forged or cast piston stock?

If youre racing motocross, id replace piston and ring every 20 hours. Harescrambles probably longer, trail riding ALOT longer. Its all up to you and how lucky you feel! 20 hours is more of a preventive thing than a need thing!

The forged piston Husky uses is a quality piece. If it is in spec for clearance and isn't showing any abnormal wear, it isn't a must for replacement. As smoke said it is an advised preventitive if you are consistantly ringing its neck at 12+k rpm. There are any number of guys that race their Husky tiddler for close to a 100 hours on the stock piston. Personally I am going to inspect the piston and let its condition dictate how I proceed. Of course a new piston kit isn't going to break your bank either.

Changing your original 125 top end to a 144 does make for a nice insurance policy. It is just a matter of how long you plan on keeping the bike and if you are going to have a need for the 125 top end in the future. I always have extra top ends on the shelf so I will never have down time and I don't race, I just don't want to ever miss a chance to ride because of a problem. Most people would consider this excessive but I am at that point where the total number of rides left in my life is a relatively small number.

Took top end off and cylinder and piston look good just normal discolor but no nick or wear I can feel with finger nail. Ring end gap is .025" and has sharp edge but no black under ring groove on piston. So I guess I will just put new ring on piston and put it back together with new gaskets. Thanks for help.