Kawasaki Z125 Big Bore Kits - 143cc & 155cc Kit

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About Kawasaki Z125 Big Bore Kits - 143cc & 155cc Kit
Prepare to offend your Grom riding friends... TB 143cc Big Bore Kit, Race Head V2, and Intake Manifold Kit – If looking for more power for your Z125, you’ve come to the right place! The parts in this kit were developed to work flawlessly with each other to deliver a high level of performance at an affordable price. While we sell each part of this kit separately, running the combination of the big bore kit, race head, and intake kit is where you will see the most power and performance gains for the best value.   These are high quality parts and the increased power will not disappoint. Here’s whats included in this kit: 143cc Big Bore Kit:
  • 60mm Ceramic coated all aluminum cylinder (no steel sleeve)
  • Lightweight high compression domed 60mm piston with rings, pin, & clips (will safely run on pump gas, 90-93 octane)
  • Head gasket kit – Now includes the cylinder head o-ring set and an exhaust gasket.
The all aluminum ceramic coated cylinder is not only lighter than a steel sleeved aluminum cylinder, it is harder, reduces friction (increasing power), improves sealing, and provides better heat transfer (runs cooler and cools down quicker).  Additionally,  this is the biggest bore kit you can install without needing machining to the cases (case boring). Race Head V2:
  • Forged anodized aluminum roller rockers
  • Huge 30mm intake and 24.5mm exhaust valves
  • Stainless Steel Valves (21-4N material)
  • 27mm intake port, 23mm exhaust port
  • Race Camshaft V2-1 (TBW0473)
  • Cam Sprocket
The combination of the above features in this Race Head V2 deliver huge power gains over the stock basic OEM cylinder head. Intake Manifold Kit:
  • Port matched to the Race Head V2
  • Enlarged 26mm port on throttle body side to work better with bored throttle bodies (also works well with stock throttle body)
  • Includes a port matched heat stop to prevent heat transfer to the intake (cannot run a heat stop with the stock intake manifold and some aftermarket head spacers)
  • Includes all mounting hardware
  • Includes a heat sensor extension harness so it can be relocated to the tappet or cam cover.
This intake manifold will ensure you will get the most power out of the Race Head V2! Add a stroker crankshaft for even more power!  The 55mm stroker crank increases engine displacement and compression.  If you add it to the: 143cc Big Bore Kit, will increase displacement to 155cc  

7 reviews for Kawasaki Z125 Big Bore Kits – 143cc & 155cc Kit

  • Glen Reed (verified owner)

    I only did the 143cc Kit with V2 Head and primary gear. Straightforward installation , basic mechanical skills and a manual will see it installed in about 3 hours. Get the Bazzaz with MNNTHBX 144 map installed and it will run perfect (ith Yoshi and MTAKE) I weigh 250Lbs and it will hit the rev limiter going uphill

  • Justin Markwalter (verified owner)

    This is the power that we all wish we had when we first picked up our bike. It’s nothing out of this world crazy but enough to keep the butthole puckered. I have beat the crap out of mine, from track use and deals gap WIIIIDE OPEN all day long. Zero problems and 100% satisfied with my 143cc kit! Thanks boys!

  • Phil Harlum (verified owner)

    I fitted the 143 kit with V2 head in conjunction with the Mtake and Bazzaz, increase in performance was fantastic with , most importantly for me, a massive increase in hill climbing ability. my Z125 that was already fitted with a Pro Circuit pipe will now pull redline in 4th on a flat road with my 110kg on board easily.

  • Matthew Purcell (verified owner)

    Purchased the 155c kit along with the mtake , bazazz tuner and Yoshi exhaust and I am absolutely blown away on the performance of my z125 pro now . This is the go to kit for peak reliable performance . You can’t go wrong buying from mnnthbx , they have the knowledge and experience with these kits and they will send you a custom map for your kit for free and are extremely responsive if you have any questions .

  • Robert McDonald (verified owner)

    Got the 143cc kit. It is exactly the power that I was looking for out of the bike. Gets to 60mph and goes uphill with ease. Should’ve done this day 1!

  • Mason G

    Composimo makes the necessary flange you’ll want to get prior to installation that will allow use of the stock heat sensor with the aftermarket intake manifold for this application. It’s highly recommended you pick one up for 35 bucks. Besides that, this kit was very simple to put on, though it took me almost nine hours.

  • GromsR4girlybois

    I installed the 143 kit with the v2 head and now I can smoke all those blue haired grom hippies with ease. Goes uphill so good and wind doesn’t slow me down anymore. I can run down the hwy at 60 mph no problem. I am doing a sprocket swap to see if I can hit 65 on the hwy and I’m sure it will do it. I recommend this big bore kit and am confident that you will love the power increase.

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