• Out of stock
    Aluminum Rocker Shaft Plug & O-Ring Set. Set includes 4 Plugs and 4 O-Rings. Allen Socket Head Type. Fits: All XS/TX 650's 1970-84. Part #05-0081 $20.95 Ea.
  • Out of stock
    1Pc. #93310-62660 Needle Bearing. Fits: All XS/TX 650's (1970-84) right or left side - (256 or 447 engines). Part #05-0100 $12.95 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.
  • 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.
  • 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 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 
  • 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
  • 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
  • Stock 22 Tooth 5th. Main Gear (located on final output shaft). Replacement for original gear - OEM Ref. # 256-17251-04. 5th. gear commonly wears out and the engagement dogs causing the transmission to slip out of 5th. gear. Replace this gear if you have this problem (cases must be split to install). Fits: XS650's 1978-1984 Only! Note: Yamaha changed the shape of transmission gear teeth from 78 on and this is indicated by lines cut into the crest of each tooth.   Part #05-0857 $46.95 Ea.
  • Out of stock
    5th. Overdrive Gear for Yamaha XS650 (1978-84). Heiden Tuning original design and source. Makes 5th. Gear taller ( higher top speed in 5th. but less torque and vibration ). 24 Tooth 5th. Pinion Gear. Replaces 23T 5th.Pinion Gear, lower 4 gears remain the same. Fits: 78-84 only ! Note : Yamaha changed the shape of the transmission teeth in 77 and this is indicated by a line on the crest of each gear tooth. This is a "Race" part and carries no warranty other than for defects in material. Engine needs to be opened to install.   Part #05-0870 $44.95 Ea.
  • Clutch Adjuster Cover - Chrome - Covers adjuster screw in LH crankcase cover. Fits: 1971-84 650's. Part #09-6589 $6.00

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