• Sale!
    Piston Ring Set - 4th. Oversize - 1.00mm. (for 1 Piston). OEM Ref.# 447-11610-40. Fits: TX/XS650's 74-84 (447 & 533 type engines) Note: 447 type rings interchange with European 533 rings but pistons do not. 447 rings do not interchange with original 256 rings used on 1970-73 models. Part #05-0024 $25.20 Ea.
  • Out of stock
    New XS Performance Street Cam - 447 Type - But with 1970 XS1 Grind by Web Cam ( Includes a $50.00 refundable core charge ). Part #05-0079 $249.00 Ea.
  • Out of stock
    Dowel Pins for Cylinder Head or Base - Pk./2 - 14mm. OD. x 16mm. Long. Fits: All 650's 1970-84 Part #05-0740 $5.70 Ea.
  • Sale!

    Piston Pin Clips

    $1.00
    Piston Pin Clips (Pr.) to fit our Big Bore (750cc.) forged pistons and Big Bore Kits. 20mm. size for 447/533 (1974-84) type engines only Part #05-0748 $2.00 Ea.
  • Sale!
    Piston Pin for our XS Forged Big Bore 750cc. Pistons. 20mm. piston pin is internally tapered to ends to reduce weight. Fits: 1974-84 447/533 XS Performance 80-81mm. Forged Pistons. Part #05-0749 $10.40 Ea.
  • Sale!
    Big Bore cylinder and piston kit- The only complete bolt on big bore 750cc Big Bore Cylinder and Piston Kit The Only complete bolt-on Big Bore 750cc Cylinder and piston kit ever made for the XS650 Yamaha 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 Fits: 1974-84 447 Type Engines Kit Includes: 1. 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. 2. Forged 80mm. 750cc Big Bore Piston kits(2) complete with Ring Sets, Piston Pins & Clips. Forged 447 type Pistons feature: 1. Valve pockets cut for large valves. 2. Mos2 treated piston skirts. 3. Oil channel for enhanced piston pin oiling. 4. 20mm. piston pins that are internally tapered to ends for weight reduction. 5. Lightweight 9:1 compression pistons. Assembly - Weight approx. 455 Grams. 6. Big Bore Cylinder Head Gasket & Base Gasket. Fitted with our XS Performance Camshaft, Dellorto 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. See Dyno Chart 1 Dyno. Note: Stock Cylinder bore size is usually about 75mm. Stock Piston size is around 74.945mm. and the Standard size piston has.945 marked on its top (the "74" is always  dropped). Standard original piston size varies slightly so the piston may also be marked .965 or otherwise. Standard bore clearance is 0.0020- 0.0022 in. ( 0.050- 0.055mm). Oversize pistons are marked in mm. A 1st.over piston is marked 0.25 which is equivalent to 10 thousandths of an inch . 2nd. OS is marked 0.50 etc. Top and 2nd. Ring End Gap (measured in cylinder) should be a minimum of 0.008" and Oil rings should have a minimum gap of 0.012". Part #05-0750 
  • Replacement Piston Ring Set to fit XS Performance 80mm. Pistons. Set = Rings for one 750cc. XS 80mm. (Standard Size) Piston.   Part #05-0751 $29.50
  • Sale!
    Big Bore (80mm.) Piston Kit - for 750 Engine Kit for Yamaha XS650's. One Forged Piston, 1 Ring set, 1 piston Pin, 1 set of rings for one piston. Features: Valve pockets cut for large valves, 2. Mos2 treated piston skirts. 3. Oil chanel for enhanced pin oiling. 3. 20mm.piston pins that are internally tapered for lighter weight. Piston weight approx 455 Grams. Fits : 1974-84 Part #05-0752 $83.95
  • Sale!
    Big Bore (81mm.) 1st. Oversize Piston Kit - for 750 Engine Kit for Yamaha XS650's. One Forged Piston, 1 Ring set, 1 piston Pin, 1 set of rings for one piston. Features: Valve pockets cut for large valves, 2. Mos2 treated piston skirts. 3. Oil chanel for enhanced pin oiling. 3. 20mm.piston pins that are internally tapered for lighter weight. Piston weight approx 455 Grams. One Big Bore needs two Kits of Piston . Part #05-0753 $83.95 /Kit 
  • Sale!
    Replacement Piston Ring Set to fit XS Performance 81mm. Pistons ( XS# 05-0753 ) Set = Rings for one 81mm. (1st. over) piston. Part #05-0754 $29.80
  • Sale!
    Cylinder Sleeve for Big Bore (750cc.) 80mm. Pistons. Note: Stock cylinder sleeves must be removed and the cylinder block Must be bored to accept this larger sleeve and then the new sleeve must be bored to accept the new larger big bore pistons. Part #05-0757 $82.95
  • Out of stock
    Stock 650cc. Cylinder Sleeve. Replaces damaged or worn out original sleeve so engine can go back to stock piston size (approx. 74.94mm. or 2.95" ) or any of it's oversizes. ID, OD, length and thickness dimensions are the same as original. Fits: All 1970-84 stock cylinder blocks. Note: After installation of sleeve into your cylinder, sleeve must be sized (bored/honed) to accept the pistons you are using. This operation should be performed by a competent professional machine shop Part #05-0758 $82.95
  • Sale!
    Big Bore Cylinder Block with cylinder sleeves installed and finished to fit 80mm. (79.94mm. (750cc. ) Note: Block only No pistons included. This cylinder is for those that have their own ( Hi-Compression ) pistons. Fits: 74-84 447/533 type engines. Cylinder casting has larger fins that extend out the same distance as the head fins for enhanced cooling. No modification needed to engine cases. Part#05-0759 $300.00
  • Out of stock
    Gasket - Cylinder Head - (77.5mm), OEM# 256-11181-01. Fits: XS1/XS1B 1970-71 Only! Part #18-0676 $24.95
  • Out of stock
    Base Gasket for Big Bore 750cc Cylinders (85mm. OD sleeve size). Stock type stud holes (dowel pins are used). Fits: Our #05-0750 Big Bore Kit. Part#18-0749 $10.95
  • Out of stock
    Big Bore Cylinder Head Gasket (750cc. - 82mm.). Fits: Our XS Performance #05-0750 Big Bore Kits for 1974-84 447 type engines. Part# 18-0750 $32.95

Go to Top