<DIV>One thing YS's DON'T suffer from is bearing life. I ran a two-stroke Irvine .72 in my Ultimate KAOS, flying a couple of times a week + the local contests. Always ran it dry, used after-run oil and never ran it lean. I had to change bearings 4 times in two seasons. One of the first signs of bearing wear was a need to bump up the idle trim to maintain idle speed. The bearings always showed signs of corrosion (not red rust, but dark stains on the races) and the inner race was very loose compared to a new bearing. My YS and Saito motors, run under nearly identical conditions, never showed signs of bearing corrosion or wear the way the two stroke bearings do, without running them dry or using after run oil . At first I thought it was due to the fact that four strokes don't draw raw fuel into the crankcase (true for Saito and OS), but YS motors do push raw fuel through the crankcase. I am currently at a loss to
explain the difference. Maybe temperature? The cooler running two-strokes allow raw alcohol to sit in the crankcase perhaps? Maybe YS has a magic bearing supplier? </DIV>
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<DIV><BR><B><I>Troy Newman <troy_newman@msn.com></I></B> wrote:</DIV>
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<DIV><FONT face=Arial size=2>The Bearings in my YS's all run long time...I know I have one motor that has 2 years on the bearing and I would say 800+ Flights.</FONT></DIV>
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<DIV><FONT face=Arial size=2>I run a good quality fuel and use an air filter....especially when flying on a grass runway....</FONT></DIV>
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<DIV><FONT face=Arial size=2>They last forever seems like....I have only changed a bearing in a YS as prevention, since I was already re-building it. Bearings were fine just did them because even $20 for a bearing is cheap.</FONT></DIV>
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<DIV><FONT face=Arial size=2>I rarely even hear of guys having their YS's with bearing problems....the 2 strokes seem to have the Bearing problems. I guess its good they are easier to work on than the 4 strokes.</FONT></DIV>
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<DIV><FONT face=Arial size=2>TN</FONT></DIV>
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<DIV style="FONT: 10pt arial"> </DIV></BLOCKQUOTE></BLOCKQUOTE><BR><BR>Bob Kane<br>getterflash@yahoo.com<p><hr SIZE=1>
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