YL82
Perpetual Restorationist
Original Measurements
1976 XS650C, ~14,000 miles.
Stock Bore: 75.004 mm (2.95290"). "004" scribed into both cylinders near bottom.
Pistons: 74.953 mm (2.9509") "953" printed atop both Piston Crowns.
Original Piston Clearance: 0.051 mm or 0.002"
Current Measurements
Left & Right (Measurements were identical on Left & Right)
TOP (1st measurement taken parallel to crankshaft, 2nd taken perpendicular...)
2.9544"
2.9544"
MIDDLE:
2.9539"
2.9544"
BOTTOM:
2.9530"
2.9530"
OD PISTON Measurements @ Piston Skirt: Taken 10mm up from bottom edges of the pistons.
PISTONS: 74.955 mm or 2.951" for both L & R.
Crunching The Numbers
I calculate the Piston to Bore Clearance to be:
2.9530" (Min. Bore) - 2.9510" (Max. Piston). = 0.002"
Cylinder Bore Taper: 0.0014"
I'm thinking that I just need to hone the cylinders to remove glaze, use my Pistons (have em' cleaned up real shiny) and go with new 1st OS Rings and grind them down to proper ring gap.
No, I've not used a feeler gauge. Was planning to wait until I get in new rings.
Comments?
1976 XS650C, ~14,000 miles.
Stock Bore: 75.004 mm (2.95290"). "004" scribed into both cylinders near bottom.
Pistons: 74.953 mm (2.9509") "953" printed atop both Piston Crowns.
Original Piston Clearance: 0.051 mm or 0.002"
Current Measurements
Left & Right (Measurements were identical on Left & Right)
TOP (1st measurement taken parallel to crankshaft, 2nd taken perpendicular...)
2.9544"
2.9544"
MIDDLE:
2.9539"
2.9544"
BOTTOM:
2.9530"
2.9530"
OD PISTON Measurements @ Piston Skirt: Taken 10mm up from bottom edges of the pistons.
PISTONS: 74.955 mm or 2.951" for both L & R.
Crunching The Numbers
I calculate the Piston to Bore Clearance to be:
2.9530" (Min. Bore) - 2.9510" (Max. Piston). = 0.002"
Cylinder Bore Taper: 0.0014"
I'm thinking that I just need to hone the cylinders to remove glaze, use my Pistons (have em' cleaned up real shiny) and go with new 1st OS Rings and grind them down to proper ring gap.
No, I've not used a feeler gauge. Was planning to wait until I get in new rings.
Comments?
Last edited: