YS valve not the only problem

[John Ferrell]

When you have a spare engine, you seldom need it!
When you don't, it happens a lot!
Some variation of Murphy's law I think.

I cannot recall ever seeing a failed front bearing. They are cheap so I usually replace with the rear anyway.

Inspect the case & crank for signs of the bearing having turned & damaging the fit. 

Just a reminder: The cam MUST come out before you remove the crank! Mark the gears carefully. It takes above average patience to find the correct timing the hard way. Few pattern flyer posses that much patience.

John Ferrell    
http://DixieNC.US

  ----- Original Message ----- 
  From: Ken Thompson 
  To: discussion at nsrca.org 
  Sent: Thursday, June 09, 2005 6:40 AM
  Subject: Re: YS valve not the only problem


  I'll check them out, Bob.
  Thanks,

  Ken
    ----- Original Message ----- 
    From: Bob Pastorello 
    To: discussion at nsrca.org 
    Sent: Thursday, June 09, 2005 6:16 AM
    Subject: Re: YS valve not the only problem


    Two on RCU right now, Ken.

    Bob Pastorello
    www.rcaerobats.net
    rcaerobob at cox.net
      ----- Original Message ----- 
      From: Ken Thompson 
      To: discussion at nsrca.org 
      Sent: Thursday, June 09, 2005 5:03 AM
      Subject: Re: YS valve not the only problem


      John,
      Everything checks out except the crank movement.  The new bearings are being ordered today and I'm going to see Verne when I get them.
      All should be well shortly.  
      I am still in the market for a good YS-91AC if you know of anybody.

      Ken
        ----- Original Message ----- 
        From: John Pavlick 
        To: discussion at nsrca.org 
        Sent: Thursday, June 09, 2005 12:41 AM
        Subject: RE: YS valve not the only problem


        Ken,
         Does it start Ok after it cools off? Make sure you set the valve lash correctly. You shouldn't have a lot of movement in the crank. That's another problem. At this point it is probably worth sending it in for service. Most of the guys I know that are flying YS have a backup motor - probably would be a good idea to find a second one. That way you can get the plane in the air while your motor is out for service. Before you send it in though, check the compression and the valve lash. You might find something there.
        John Pavlick
        http://www.idseng.com
          

          -----Original Message-----
          From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Ken Thompson
          Sent: Wednesday, June 08, 2005 9:05 PM
          To: discussion at nsrca.org
          Subject: YS valve not the only problem


          I just fired my YS-91 up after the valve cleaning.  It fired immediately and had plenty of power while still running rich.  After running for a minute or two the rpm's started fluctuating a bit.  The more it ran the less rpm's I was able to maintain.  I heard a noticable rattle that seemed to be coming from the engine area.  After the engine ran for about 5 minutes, the rpm's started to drop more.  I leaned the needle a little and the revs didn't increase, so I richened it back up and idled down, the motor died.  I felt the spinner to see if it was warm and it wasn't, that's when I noticed the movement of the output shaft.  My first thought is the front bearing, I have quite a bit of movement up and down and a little side to side.

          I guess I'm not meant to fly this plane.  Does anybody know where I can get a good YS-91, cheap?

          I think this one is going back to YS.

          Ken
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