[Suleku]

I'm super confused when it comes to picking a big bore kit to buy for later.... What is the difference between these two and which one I should get in the future... I'm looking for more top speed out of my 2018 Z125 pro... Much advice would be very helpful

Mnnthbx (Big Bore Kit)

TB 178cc (Big Bore kit - Amazon)

Just a Side note: I just got my engine tuned using a Hoedar ECU today soo a fuel controller is already covered

 

[Ls13ater]

143cc you don’t have to bore your case for the cylinder to fit, if you split the case you can add a stroker crank to make it 155cc, but if your going to split the case you might as well bore it why it’s apart, I would not put a 67 mm bore piston(178cc), because the area between the head stud and the cylinder get rear thin, it’s more prone to let a head gasket leak, I have a 64mm bore with the stroker crank making mine 177cc it a strong bike but a nice 155cc deal runs really well

 

[crakerjac]

Difference between your MNNTHBX and Amazon links are that MNNTHBX is includes a V2 head and the Amazon link is just the jug. That's the big driver for the price difference. You are also looking at a 143cc jug and head vs a 178cc jug only.

I don't know for sure if the 178cc jug will work with stock head.

 

[Kaw'ee]

I'm super confused when it comes to picking a big bore kit to buy for later....

Use chart to see HP required for your wanted top speed goal

 

[Somefun]

I just ordered the

143cc you don’t have to bore your case for the cylinder to fit, if you split the case you can add a stroker crank to make it 155cc, but if your going to split the case you might as well bore it why it’s apart, I would not put a 67 mm bore piston(178cc), because the area between the head stud and the cylinder get rear thin, it’s more prone to let a head gasket leak, I have a 64mm bore with the stroker crank making mine 177cc it a strong bike but a nice 155cc deal runs really well

I just ordered the 165mm with the stroker crank and the 2v race head. I have the 143cc with the 2V now but wanted to bump it a bit more. The kit come with everything they say. Race cam, injector and manifold. Looking forward to the build. If anyone is interested in the 143cc cylinder and head I have I’ll most likely be seeing it. Comes complete. What are you guys using for oil coolers?

 

[Ls13ater]

Moral cooler, i tried the China cooler, i tap it into the head oil feed, it did not work well so I just switched over to one with the sandwich plate that I know works well on a friend bike, private message me what you want for the v2 head