Awhile back, I did a parts comparison at majestic honda and the only difference in part numbers for the major components that you mentioned are the pistons so I believe that is where the compression ratio difference occurs.
When rebuilding the engine, you can order an oversize piston. That part number is the same for both models so you may be able to modify the CVT compression ratio during an engine rebuild (assuming the oversize piston is designed for the compression ratio of the MT model).
There are actually many components that are different for lean burn. Besides the main ECM (computer), there is a different catalytic converter. Here is a portion of the description from
http://www.insightcentral.net/encycl...catalytic.html
During lean burn operation, the exhaust gas contains a larger percentage of oxygen (O2) and NOx, the NOx being primarily nitrogen monoxide (NO). The platinum catalyzes the O2 and NO to produce nitrogen dioxide (NO2), which is able to be stored on the Ti-Na surface.
When it determines that the Ti-Na surface is saturated, the Insight temporarily richens the mixture. This action decreases the NOx and O2 in the exhaust, and raises the levels of hydrocarbons (HC) and carbon monoxide (CO). The platinum is then able to use the HC and CO to catalyze the NO2 (that has been stored) into harmless nitrogen gas (N2), carbon dioxide (CO2) and water vapor (H20).
Even the fuel lines are different between the two models....So I believe it would be very difficult to convert a CVT to lean burn...I remember reading in this forum a long time ago that there was a Japanese CVT model that was lean burn equipped.
JoeCVT = Just your average CVT owner
Compression Ratio and lean burn
