Engine rebuilding


Fuji blue engines
OEM and aftermarket piston + ring options...

Pro 785 engine
Fuji 750 pistons instead of Pro 785 specific pistons

Polaris red domestic engines, two and three cylinder
900 & 1050 alternate firing orders
1165cc Crankshaft differences
Full circle 1165cc crank using 777cc crank webs

Weber engines (MSX 150 and MSX 110)
Nikasil plating failures


Nikasil plated cylinders
From the factory, Polaris used cast iron cylinder sleeves in all 2-stroke engine models except the Pro 785 and the MSX 140.

Pro 785 and MSX 140 cylinders are Nikasil plated aluminum (nickel matrix silicon carbide)
. There is no sleeve.
All Weber 4-stroke engine cylinders are also Nikasil plated.

Cast iron cylinder sleeves can be honed or over-bored as needed, with replacement pistons available in multiple increments larger than the original stock diameter.

Nicasil cylinders can be honed with a special diamond hone, but only minimal Nikasil metal thickness may be removed. If the cylinder wear or damage is to much for honing then the cylinder must be processed and the Nikasil coating renewed.

Note: For the MSX 140 replacement piston sources in oversize are limited, so the best approach may be to rebuild to OEM piston size, not oversized.


Well regarded for Nikasil cylinder repair and replating are Millennium and US Chrome.
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