Kawasaki Fury 125

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Kawasaki Fury 125

How to Modify your Fury 125 Engine

Kawasaki Fury 125 and the Kawasaki Aura Nexus shared the same engine respectively. If you know this Kawasaki Aura before then, I can say that it is a monster champion underbone bike. Why? Mr. Google will explain everything to you about this Kawasaki Aura Nexus legacy in racing world in respect with Sir Jolet Jao of Kawasaki Racing Team way back 2003, full information.


Thrilled? Excited? I am sure you are. I felt this also when we started a Fury project bike last 2009. It is indeed a big pleasure for us to modify such beast underbone bike that time. The result is superb, and I can still say now that this underbone racing machine will be going to kick some ass inside the race track!. I know you will going to enjoy reading this! So, let’s start…

How to release the monstrous racing machine inside of your Kawasaki fury?.  A great question and truly needs a great answer. Before we begin, I would like to formally introduce to you this Furious underbone bike’s full specification.


  • ENGINE TYPE:                     SOHC Single Cylinder Type
  • STOCK DISPLACEMENT:      125cc
  • BORE and STROKE:              56.0  x 50.6 (mm)
  • COMPRESSION RATIO:        9.8 : 1
  • COOLING SYSTEM:              Air-cooled
  • FUEL SYSTEM:                      KEIHIN PB20
  • LUBRICATION:                     Fuel Lubrication ( Wet Sump)
  • IGNITION SYSTEM:              Magneto DC-CDI
  • SPARKPLUG:                        NGK C6HSA or DENSO U2OFS-U
  • STARTING:                           Kick and Electric Starter


  • MAXIMUM TORQUE:          0.94/6500 (Kgf.m/Rpm)
  • MAXIMUM POWER:            9.65/8000 (Hp/Rpm)


  • DRIVING SYSTEM:               Chain Drive
  • CLUTCH TYPE:                      Wet multi-disk and Centrifugal
  • TRANSMISSION TYPE:          4-Speed Rotary


How to modify your Fury and upgrade it to 138cc, 143cc, 151.5cc to 183.7cc?

[sociallocker id=”585″][/sociallocker]Yeah right, you can upgrade your engine’s displacement with the help of bore-up kit and stroker kit. You can use 59mm bore kit to gain 138cc engine displacement and 60mm to upgrade it to 143cc. These bore kit sizes are both proven safe to use for your engine’s stock cylinder head and crankcase. In most cases, it is still advisable to modify your cylinder head by porting and polishing the exhaust and intake ports. To get rid with over compression Port and Polished modification process is required if you don’t have a bigger valves cylinder head. Stage 1 and 2 racing camshaft will surely boost the engine torque and power with this kind of set up. 24mm round-slide carburetors for touring and daily use or 24mm flat-slide carburetor is a must, to power up these bore kit sizes. With the help of full race ignition system ( Racing C.D.I, Racing Coil with high tension wire and Iridium Racing Sparkplug) your bike could run at its maximum speed. By the way, you can use the Racing C.D.I of Yamaha Mio Amore and Sporty for your Yamaha X1.

How can you upgrade to 151cc? Adding up the safest stroker pin size which is 1.5mm will answer your question. If you use 60mm + the additional 1.5mm stroked up kit is equivalent to 151cc. How? Thru the help of this ENGINE DISPLACEMENT FORMULA ( Bore x Bore x stroke x 0.0007854 = Displacement CC), for the complete information, please click here. The maximum additional stroked up kit size that you can use to your Fury’s engine is +3mm. We made this project engine before; this is the reason why we already know what the best for your Fury is. 60mm bore + 3mm stroked up pin = 160cc engine, and this is the output displacement of our project bike before. We struggled a lot in purchasing this +3mm stroked up pin for Kawasaki Fury, there is no aftermarket stroked up pin mainly for our Fury that year. Our race mechanic ( JOVICWORX) decided to use the other bike stroker pin, to be specific, we use a Yamaha X1 stroker pin. Luckily, they have the same size of stroked up pin ( Fury and X1/Lagenda) the rest is the best ahaha…

 The Monster 183.7cc and 205cc Takegawa Racing Modification


It may sound exaggerated and boasted but believe it or not this is a fact, this is real. I remember when I saw these racing parts on the internet and do some serious research about them. I found out that Sir Jomar Arcega is the only supplier of Takegawa Race Parts here in the Philippines. 68mm bore-up kit with 2 Big Valves Super-head with complete paraphernalia such as Racing Camshaft, Rocker Arms, etc. I was shocked when I found out that they have the 4 Valves Superhead; also, that’s WOW!!. The only problem is the price of this fantastic kit is also a big WOW! ahaha.. You can purchase the whole set for 68,000 Pesos and jack up kit as shown in the photo is not included. You need to buy all the outstanding race parts that will compliment with this kind of racing equipment. You need a 28mm or 32mm racing carburetor for the 183.7cc, complete full ignition system and an oil cooler or radiator kit. You also need to bring your crankcase to the Precision Shop and do the milling job for the 68mm bore size. Yeah, it is indeed insane, but if you completed this kind of project, then that’s ideal for you. So, let’s jump to 205cc beast engine set. If you are not happy with this 183.7cc upgrade, you can still add more engine displacement to it if you want to. You can use +3mm stroked up kit or jack up set to make your dream come true.  I think 183.7cc with 4 Valves Super-Head would make me feel safer instead of using stroked up pin.  This is the secret of your Kawasaki Fury engine.

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