YS 624T Compression...

[Northern...er]

Installed new piston rings Dec 2008 as the comp. was down to the lower limit (according to MY manual) of 43/44... (and increased with a drop of oil in the spark plug hole)...  Haven't checked the NEW compression yet, but I do recall the upper figure was only 57...  (which is different than what someone posted) -- anyway... operation successful, as the engine now runs clean - no more blue smoke on startup.  A great machine, worth the investment... I only hope I can find the rubber tracks when these ones crack right thru & fall off...!

[Underdog ()]

 The manual (downloaded) says the pressure should be 49 to 78 psi for the 8hp YS-828 and it says the  6hp Yamaha snowblower has a recommended pressure range of pressure range of 57 to 85 psi.  Is this the spec that you decide to use?
Did the new rings give you better performance?  How expensive was the whole job?

[Underdog]

I did see a different compression range listed in a manual I downloaded for YS624T and YS624W blowers with metal tanks. That range (0n page 7-3) is listed as 43 psi to 57 psi.  I'm not sure why there is such a huge difference between the two service manuals.

[Northern...er]

Ring set was very reasonable thru Speedy/YamahaGenParts (under $30)  Also the head gasket was cheap (should be new).  Still haven't re-checked the comp. - will probably post that & pics sometime - when I have the chance & time.... and Internet!