Norton 850 Commando 77mm Piston Set Complete w/Grant Piston Rings PN# 06-3838 06-7958 US

Here is a complete piston and piston ring set for the Norton 850 Commandos that delivers top performance at an economical price. The cast JCC/Emgo reproduction pistons have been the industry standard for street use for years. We have combined the piston set with a set of high quality Grant piston rings, featuring a one-piece oil control ring for easy fitment. Available in standard and oversizes up to .060″.

Marketed by Emgo, the JCC pistons are precision manufactured to exacting standards and include the wrist pins and circlips. The US-made Grant piston rings are a complete set of (4) compression rings and (2) oil control rings, enough for both pistons. The compression rings are marked with “top”, indicating the orientation in the piston ring grooves.

The pistons must be fit to the cylinder barrels when overboring. The machinist measures the pistons and performs the cylinder boring and finish honing to a specified clearance. The piston rings are checked and adjusted for the proper end gaps prior to fitment to the pistons. It is advisable to replace all of the top end gaskets and sealing washers when pistons and piston rings are renewed.

Failure to achieve proper fitment of the pistons and piston rings can result in a noisy engine, with high oil consumption. Following the proper installation procedures, as outlined in the factory workshop manual is recommended when fitting new pistons and rings. This job requires specialized tools and skills and may be best left to a professional to carry out the task.

Key Features:

• Precise Fit: Engineered to match the original Norton 850 Commando specifications.
  
• Premium Materials: Crafted from high-grade aluminum alloy for durability and heat resistance.
  
• Grant Piston Rings: Equipped with top-quality Grant USA piston rings.
  
• Improved Performance: These pistons help maintain proper compression and oil control, potentially enhancing your Commando’s power output and efficiency.
  
• Versatile Application: Suitable for various Norton 850 Commando models.
  

Technical Details:

• Sizes: Standard, + .020, +.040 and +.060 Oversizes (confirm your specific engine requirements)
  
• Complete set includes pistons, wrist pins, and circlips
  
• Grant rings provide excellent oil control and compression sealing
  

Whether you’re rebuilding your engine or simply looking to restore your Norton 850 Commando to its former glory, these pistons with Grant rings offer the perfect combination of quality, performance, and authenticity. 

Available in standard & + .020, .040 & .060 oversizes, use the drop-down menu to select your size.

Additional Items:

• Need just the pistons? Check here.
• Need just the rings? Check here