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447 Big Bore Kit with Complete Top End Gaskets

$724.95 724.95
Out of stock

Big Bore Cylinder and Piston Kit

ALL NEW PARTS!  The ultimate complete bolt on Big Bore 750cc Cylinder and piston kit ever made for the XS650 Yamaha - this set comes with all the top-end gaskets, seals, and o-rings you will need.

Kit Fits: 1974-84 447 Type Engines


Modified limited production European Race Engine Cylinder Block has enlarged fins for improved cooling. The New Cylinder Block has longer fins matching the Head Fin Length.

Kit Includes:

 One of our XS Performance Big Bore Race Cylinder Block with sleeves installed and finished to fit our 80mm. Forged Big Bore (750cc.) Pistons. Cylinder casting has larger cooling fins that extend out the same distance as the cylinder head fins for enhanced cooling. No modifications to engine cases needed.

Two 80mm, 750cc Big Bore Piston kits complete with Ring Sets, Piston Pins & Clips.

Precisioned machined 447 type Pistons feature:

                    a. Valve pockets cut for large valves.

                    b. Oil channel for enhanced piston pin oiling.
                    c. 20mm. piston pins that are internally tapered to ends for weight reduction.
                    d. 9:1 compression pistons. 

All these gaskets, seals and o-rings...  all you need.

1 - Performance (big bore) Cylinder Base Gasket XS650 - 18-0749

1 -  Cylinder head gasket  Big Bore XS650 -  18-0750

4 - Cylinder Head Sealing Washers - 01-0650

1 - Top End Engine O-Ring Set - XS1 - XS2 - XS650 - 18-0855

1 - Top End Copper Sealing and Washer Kit - XS650 - 18-0870

1 - O-Ring - Cam Chain Adjuster Cover (Nut) - 18-0867

2 - Gasket - Rear of Advance or Breaker Housing XS650 - 18-0863

1 - Camshaft Seals - TCI Motors - 25-40-7 - 01-9020 

1 - Headpipe Exhaust Gaskets - XS650 - SR500 - XT500 - Pkg 2 - 18-0675

1 - Drain Plug Gaskets - Copper - Pkg 2 - 17-3802

4 - Tappet Cover O-Ring - Yamaha - XS650

Fitted with our XS Performance Camshaft, Carbs, a free flowing Exhaust and Iridium spark plugs will result in about 65 Rear wheel Horsepower or more and 50 foot pounds of Torque.

Dyno Chart 1 Dyno Chart 2

Is Universal Part: No

OEM Number(s): N/A

Motorcycle Fitment: N/A