Piston & Rings

Joined
Jun 25, 2002
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#1
I have a 91 KDX 200 (Oz Spec) thats has done 4600k's (2850m). When & how often should the piston & rings be replaced. I have owned it for nearly 4 years and only added about a 1000k's (621m) in that time and don't believe that they have ever been replaced.
Still has plenty of power though.
I also noticed after my last ride that smoke was coming out of the KIPS resonator breather pipe. is this normal?
Is it time for a strip down & clean of the KIPS & new piston & rings?
 
Joined
Jun 3, 2006
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#2
I would give it a compression check. Should be over 100 PSI (125 even better), anything below this is weak. Another good indicator is how it starts. The first indicator that compression (rings) are getting weak is that the bike starts getting harder to start. Instead of 3 or 4 kicks like normal to start, it starts taking 10. Most 2 strokes of this size and performance levels should get about 4000 - 5000 miles on the piston and rings.
 
Joined
Jul 4, 2005
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#3
There is an oil seal and / or o-ring inside the KIPS. It may have worn out. I would definitely have a tear down, clean and inspection if it had that many kilometers on it. Parts that may still be within the measured tolerance may explode due to the combined stress over time.