Expected rpm on 120ac

[John Ferrell]

Spitting excess fuel is sometimes excessive rotary valve clearance. Don't forget the locking setscrew if you go there!
In my experience, AC's don't always look impressive on the ground runup.

John Ferrell 
6241 Phillippi Rd
Julian NC 27283
Phone: (336)685-9606  
johnferrell at earthlink.net
Dixie Competition Products
NSRCA 479 AMA 4190  W8CCW
"My Competition is Not My Enemy"

  ----- Original Message ----- 
  From: Del Rykert 
  To: discussion at nsrca.org 
  Sent: Wednesday, July 02, 2003 10:35 PM
  Subject: Expected rpm on 120ac


  Would appreciate opinions.

  I have a YS 120ac that has been a strong runner in the past. Would turn a 15x12 apc 8300-8400 on 25% powermaster. It was rebuilt last season but never run till this season. It was giving me fits at Hamburg contest and taching is only showing 7800 to 8000. Needle 1 1/4 out. Seems to spit more fuel out of air inlet than I used to see. 

  My question being am I being unrealistic expecting it to continue to give me 8300-8400 on that prop & fuel. Valves check at 002 piston TDC cold. Good seal in valves. Don't feel any drag from bearings but I replaced bearings last time and was surprised on ratty they were after dis-assembly. Might my bearings be the culprit and next item to explore?

  TIA for all who reply.

    If you choose to reply off list...   drykert at rochester.rr.com 

       Del K. Rykert
       AMA - 8928 
       NSRCA - 473
       Kb2joi - General 


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