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Old 06-27-2006, 11:31 AM   #1523
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Originally Posted by afm
What do you mean it's not "True ABC" ?? The Specs for the engine says so:

-Natural aluminum construction Nine fin blue aluminum cooling head
-Two-piece turbo cylinder head with 29mm innner and 49mm outer head
that adds extra area for more efficient cooling
-Slide Carb 11H - 3 needle slide valve carburetor with ROAR/IFMAR legal 5.5mm carb restrictor
-Rear Exhaust
-ABC construction, Aluminum piston and Brass liner that is Chrome plated
-High tensile A7075 "knife edge" aluminum connecting rod double bushed for friction-free operation.

Donít confuse compression with pinch, Sleeve Pinch is not that important contrary to popular belief. The question is how well does it seal as soon as the piston starts to close the exhaust port and if it holds compression after you roll it to top dead center.
Place a few drops of after run oil trough the top (removing plug), then place plug in place, then roll piston to top dead center and listen and look for air bubbles through exhaust port. If thereís none, then your engine still has compression, even if it has no pinch.
The fastest team motors we have, have zero pinch.

I am not knowledgable as anyone of you. But, my exp is that OS TZ seems to be quite durable. I had more than 8 gallons on TZ 5, and I still see a lot of compression.

My bday is coming up, and my wife finally "allows" me to buy a new engine. I like OS TZ tuned better, because I am used to tune OS engine. Plus 12-3C seems to me is a better deal, cheaper and equal in performance. But, I heard NovaRossi is harder to tune than OS engine. That is why I would to hear some comments regarding these to engines. Thx.
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