Engine Parts
Replacement Pistons  447 Big Bore Kits   Rings   Valves  Valve Seals   Cam Chains  Cam Chain Guide 

Racer's 145mm Long Rod Kit


Piston/ ring/wrist pin package is 11 grams lighter than a stock 650. Pistons are sized at 79.99mm, to allow for potential honing of existing cylinders. Reduced headland for more power and better emissions, allowed by a truly complimentary squish band. A true 10:1 is achieved. Modern ring package has 1mm top and 1.2mm 2nd ring, with a 2mm 3 piece oil ring. Connecting rod is 145mm c-c, achieving a 1.96:1 rod/stroke ratio, moving the torque peak up in the power band, smoothing the short rodís explosive midrange, increasing traction and peak power. Small end is bushed with premium C630 aluminum bronze and has 10% more area. Big end bearing has 3.5mm rollers for     less skating at high speed. Available as piston kits/rod kits only, or with sleeves, or with fitted Big Fin cylinder. ALL CLEARANCES MUST BE CHECKED!       NOT BOLT IN!

Piston/rod kits only #JCEN11-1000................. $800.00 

  Kit with sleeves #JCEN11-1005...................... $1000.00 

.Kit fitted to your cylinder #JCEN11-1012....... $1350.00


Racer's Deep Sump Extension Kit

This is a serious performance modification. It is 2 3/4' deep, lowering the oil level to free  the flywheels and primary gears from oil drag. Since the flywheel and primary gear are not immersed in oil,  there is less drag and better dyno numbers and lower oil temps. The extension is cast for better heat dissipation than ones made of billet. The kit consists of the extension, two sump gaskets and 6 stainless steel bolts. Side stand lug removal may be required on stock frames

.Deep Sump Kit. #MCEN40-2750..... $135.00





Will it make your XS engine last forever?

This replaces the filter screen in the side cover with a modern, disposable filter, available in chrome and black. It projects about 2", giving a burly, modified look. Everyone will know you love your XS enough to give it a supply of clean oil. Side cover must be removed and 2 holes drilled and 2 holes filled with J-B Weld. Kit includes: Adapter and gasket, hardware, and 620 Loctite.

4 filters available: black or chrome, with (K&N) or without safety wire---$7.49 to $16.50

Replacement filters:  Fram PH6017      K&N KN303      EMGO M82230     Vesrah VSF4005

HON 15410-MM9-013     KAW 16097-1063     YAM 3FV13440-00

Oil filter installation instructions

   Spin-on Kit        #MCEN13-44100...........$94.95  

Emgo black filter      #MCS86-4164 ..... $7.49 

   Emgo chrome filter  #MCS86-4168  .... $8.85   

K&N black filter      #MCS55-6004 ..... $14.95 

     K&N chrome filter  #MCS55-6030 ..... $16.50    


Oil Filter/Cooler Kit

No modifications are required to install this kit, which uses a common Honda filter. Housing is finned aluminum billet.

 Filter/Cooler Kit ..  #MXS15-6504  ... $149.00 ea.   

Replacement filter  #MVLE61-2460  ..... $7.00 ea. 


Light Weight Drain Plug Kit


For those of you who want to lose 7.2 oz. of dead weight or just wish to have an easier time of removing your drain plugs when changing oil, 650 Central offers a drain plug kit, with a 14mm-headed magnetic plug, drilled for safety wire. Sold each, order 2 for both plugs.

  #JCEN15-31500  ..... $30.95 ea. 




BACKORDER Billet oil cooler/filter cover adaptors BACKORDER

For those want to run a remote oil filter and/or cooler. Made from 6061T6 billet. Case must be tapped for feed line, and an internal passage must be blocked

  #JCEN13-44700  ..... $74.95   



Fits motors with 447 connecting rods (1974 and newer engines) .
We offer 2 bore sizes for these engines. 
Each kit includes (2) of the 9.2:1 compression Wiseco brand
pistons that are good for pump gas.

(2) Sets of Piston Rings, Piston Pins and Clips.
(2) cylinder sleeves and a special Big Bore head & base gasket.


80mm, 744cc Kit  #JCEN10-7500 ..... $550.00

 81mm, 752cc Kit  #JCEN10-7501 ..... $580.00   

Sleeve installation is available for $350.00 plus
shipping, call or E-mail before shipping your cylinders.

Composite Big Bore Head Gaskets  

650 Central ...043" ....KCEN11-18150... $60.00   

XS Performance .060" KMXS18-0750... $45.25 

                 Big Bore Head & Base Gasket Set  

Composite head and base gasket set for our 750 Big Bore kits.

#KCEN11-8750..... $73.00 

               Copper Big Bore Head Gaskets

Now, set your piston-to-head height for maximum performance. Available in .026", .032", and ,042". 81.5mm bore
Our composite Big Bore gasket is .043" and the XS Performance composite is .060" (1.5mm)
Need something special? CALL ME Sold each.

.026" KCEN11-18226... $48.00   

.032" KCEN11-18232... $48.00   

.042" KCEN11-18242... $48.00   

                   Big Bore Base Gaskets

Sold each. Our Big Bore base gasket is .020"

.010" Copper #KCEN11-35110... $22.95 

 .020" Fiber  #KCEN11-35120...... $13.95  

.031" Fiber #KCEN11-35131....... $13.95 






This modification helps keep the soft small end of the stock rods live, a real problem with 750s,

especially when run hard or raced. Once the copper plating is damaged, they WILL be seeking daylight.

# JCEN50-10102...... $60.00/pr  

With sleeve installation # JCEN50-10100...... $50.00/pr 


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 the 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 7mm shorter than stock.

    3. Oil channel for enhanced piston pin oiling.

    4. 20mm. piston pins that are internally tapered to ends for weight reduction.

    5. 9:1 compression pistons. Assembly - Weight approx. 455 grams vs. 394 grams for stock

  3. Big Bore Cylinder Head Gasket & Base Gasket.

 BACKORDER #JMXS05-0750...... $699.00  BACKORDER


650 Central "Street Fighter" Cam

        This cam's 100 degree lobe centers make your exhaust system work over the widest range. For '74 on up (36T) 447 motors
Stock pistons, valve guides and seals OK. Must use spring kit below.
$100 refundable core charge upon receipt of you regrindable stock cam.

BACKORDER    # JCEN28-28500...... $145.00  + $100 core   BACKORDER

Hi-Performance Valve Spring Kit

These springs are good for cams with up to .450" lift. Top retainers are  7075 T-6 Aluminum.

 Fit all XSs '72-84.

  # JCEN28-28600...... $145.00 


Replacement Oversize Pistons

These fit the 447 engines produced from 1974 - 1984.
Each brand new piston comes complete with
Piston Pin and Pin Retaining Clips. Made in Japan
to exacting dimensional specifications for replacement pistons.
Available in 1st (0.25mm), 2nd (0.50mm), 3rd (0.75mm), & 4th (1.00mm) oversize.
They are sold each, so order 2 for each engine.

Order rings below

1st over piston #JMXS05-0017 ..... $62.95

2nd over piston #JMXS05-0019..... $62.95 

3rd over piston  #JMXS05-0021..... $62.95 

4th over piston #JMXS05-0023 ..... $62.95 

Piston Rings
Quality piston rings, standard thru 1.00mm oversize bore size. ONLY for the late model, 447 motors, 1974 -1984.
STD sets ONLY feature upgraded combination compression/oil scraper 2nd ring. Sold PER PISTON, order 2 sets

STD.  #JCEN49-44700 ..... $37.00  per piston

1st over #JMXS05-0018 ..... $34.50  per piston

2nd over #JMXS05-0020..... $34.50  per piston

3rd over  #JDIX05-0022 ..... $34.50  per piston

4th over  #JDIX05-0024 ..... $34.50  per piston


Standard Size 256 Piston Rings
Quality 256 piston rings, featuring upgraded combination compression/oil scraper 2nd ring. Standard bore size ONLY

for the early motors, 1.5mm top ring, 1970-1973. Sold PER PISTON, order 2 sets

  256 STD. #JCEN49-2560 ..... $50.00  per piston


Intake Valves

OEM quality 3 piece intake valve
Sold each.

#JCEN12-11104..... $32.00  each  


Polished Stainless Steel Intake Valves

Polished stainless steel intake valve with collets.
Fits all 650s. Sold each

#JMXS05-0065 ..... $30.50  each  

BACKORDER Polished Stainless Steel Exhaust ValvesBACKORDER

Polished stainless steel exhaust valve with collets.
Fits all 650s. Sold each

#JMXS05-0067 ..... $30.50 each  


Valve Stem Seals
Sold singly. Fits 70 thru 84 engines

#KKNL14-6058 ..... $4.00  each


Cam Chains

Tsubaki cam chain, endless, better than OEM quality, fits '74 up, Merc's choice

#JTKR25-9723 .....  $64.95 

Cam chain master link, must be purchased with the above chain
(NOTE: It ONLY fits this chain),

#JTKR25-9921..... $3.95 

Tsubaki "Peanut" cam chain, endless, better than OEM quality, fits '74 up, 5% lighter. Rivet master link included.

#JTKR25-9834.....  $39.00 

"Peanut" Cam chain master link
(NOTE: It ONLY fits this chain),

#JTKR25-9922..... $3.00   

Tsubaki cam chain, better than OE quality, fits '70-73. Master link included.

  #JMXS52-5003.....  $45.75 

Spare Cam chain master link for '70 - 73
(NOTE: It ONLY fits this chain)

#JMXS01-8801 ..... $4.95 

Front Cam Chain Guide

Front Cam Chain Guide, fits all years.

  #JMXS05-0006 ..... $34.25    

Cam Chain Tensioner Arm Assembly

Cam chain tensioner arm assembly. Fits '74-84

 #JMXS05-0004 ..... $69.25 


Copper Head Stud Sealing Washers

Replace the stock sandwich washers with these copper to stop head and base gasket leaks,

 especially on built motors. 4 required.

#KCEN98-0144....  $2.95    each 



Clutch detail with spacer dimensions


Ferodo Premium Clutch Plate Kit
Friction discs, 74-79, 7 discs

#JMCS45-5005..... $100.00/ kit


EBC Clutch Plate Kit
Friction discs only

 '80-84 6 plate #JVLE39-2226..... $77.00/ kit

 '74-79 7 plate #JVLE39-2242..... $89.00/ kit


PRO Brand Clutch Discs

For 1974 - 1979, order 7 discs.
For 1980 - 1983, order 6 discs.

#JKKK39-1551 ..... $9.25   each 

Barnett Premium Clutch Plates

Barnett Kevlar clutch plates, .120" thickness
For 1974 - 1979, order 7 discs. For 1980 - 1984, order 6 discs.
Maximum bite. Not recommended for street use---unless you really need them.

#JBAR16-3210..... $19.95   each 



Replacement Steel Plates

#JMXS39-6507 ..... $6.95   each 


Heavy Duty Clutch Springs

Fits all XS
Set of 6, 14% stronger than stock
Spring free length is about 1.67".

#JSUD61-4201 ..... $19.50    set 


Heavier Duty Clutch Springs

Fits All XS
Set of 6, 27% stronger than stock
Spring free length is about 1.61".

 #JMCS45-5202 ..... $18.95/ set


Heaviest Duty Clutch Springs

Fits all XS
Set of 6, 43% stronger than stock
Spring free length is about 1.50".

#JBAR41-6000 ..... $22.95/set 


Clutch Rod Oil Seal
That pesky little clutch rod seal behind the drive side cover.

#KMXS01-9019..... $5.95  

Kick start, shift shaft, countershaft, camshaft, crankshaft, starter seals in stock

Engine Oil Seal Kits
This set contains oil seals for all years of the
TX & XS650 engine. It includes: countershaft, crankshaft,
(2) camshaft, shifter, kick starter, clutch rod,
decompression lever and electric starter seals!

#KMXS01-9010.... $46.90    

Oil Filters

Replacement Oil Filter.
This unit will replace the filter in the
right side cover On all Yamaha XS650's.
Why change your oil and not change your filter?
It's cheap insurance for your engine!

 #MMXS15-6501 ..... $13.95 

Replacement Sump Oil Filter.
The XS650's are known for a weak original equipment
sump oil filter. We rarely see one that is not torn.
Replace your torn, ineffective sump screen with the
OEM-style reinforced sump screen.
Stop those harmful contaminants before
they circulate through your engine!

  #MMXS15-6500..... $35.00    

Drain Plug Gaskets

Replacement Copper Drain Plug Gaskets.
Stop that pesky leak and keep your bike clean!
Fits all XS650's.
You get (2) copper gaskets.

#KMXS17-3802 ..... $4.50/ pr  


Three Bond Liquid Gasket

Three Bond Liquid Gasket 1194 is a semi-drying OEM approved liquid gasket formula
which forms an elastic, reliable gasket seal. It is resistant to damaging fluids, chemicals, heat,
pressure and impact. Three Bond 1104 is for metal-to-metal joints, such as the engine cases, or cylinder head cover.  We use it as a substitute for "Yamabond #4" gasket sealer on our engines.
3.5 oz (100g) tube 

#EVLE64-1415..... $11.95  each

Gasgacinch Gasket Sealer

The gasket sealer that holds gaskets in place during assembly of parts like
no other you have ever used! Comes in a 4 oz. can with a swab applicator
attached to the top. Quick drying and fast sealing formula.

#EDS17-3402 ..... $8.95