Best cylinder head

[Tilos]

Hi all, Please help me out the following question. I would like a bit more power out from my kymco (125i, 2018, KL25F), so I borought a nice big bore cylinder 160ccm. And also I planning change over the cylinder head. And this is where I got stuck. Please some one advise me wich or what kind of cylinder head do I need for better timeing? Is there exist four valve head for kymco? Or best head for 2 valve... Or any suggestion. Thx

[Ruffus]

@Tilos welcome here!
To get some more power out of your scoot you will sacrifice longevity and reliabilty.

Here in Italy people use NARAKU (pls see pic) performance kits to impress their peers for a short spell until mainbearings, CVT and crank give in, which means an economical write-off.

NARAKU for example has stages of performance kits, which include cyl.head or  cyl.head and camshafts, etc.
As a rule of thumb:
Two valve heads gives you more power from lower revvs, four valve heads more revvs and power for higher speed.

The other guys, who use this big bore kits (which I think do NOT fit without alterating the crankcase to 62mm) for competition, dirty their hands during weekdays to ride on Saturday for half an hour full speed.

I know, does not sound very optimistic but this is reality.

[Tilos]

@Tilos welcome here!
To get some more power out of your scoot you will sacrifice longevity and reliabilty.

Here in Italy people use NARAKU (pls see pic) performance kits to impress their peers for a short spell until mainbearings, CVT and crank give in, which means an economical write-off.

NARAKU for example has stages of performance kits, which include cyl.head or  cyl.head and camshafts, etc.
As a rule of thumb:
Two valve heads gives you more power from lower revvs, four valve heads more revvs and power for higher speed.

The other guys, who use this big bore kits (which I think do NOT fit without alterating the crankcase to 62mm) for competition, dirty their hands during weekdays to ride on Saturday for half an hour full speed.

I know, does not sound very optimistic but this is reality.

Thank you your help Rufus. Its clear to me increase the power will short the mile age. Well, honestly I do not want all the juice out of my scooter, but the original setup emmmm weak for me xd. I have install the new big bore a couple of days ago and I think I'm half ready.
I put the airsail bore together with naraku maxi speed variator (11.5gr rollers), and its setup run til 80km/h like a rocket. After 80+ its got slower acceleration than reach the final speed ~100km/h. So its start become something cool, and I smileing.
I tried some dr. pulley sliders as well (11 and 12gr) strange but its gave a worse acc and final speed, or same final speed with a terrible acc. I will play a bit more but I think almost done.
Regards, Imre

[Vision]

but the original setup emmmm weak for me xd.

Really? My scoot is quite strong. Will keep 50mph up steep long hills and is generally peppy. How much power do you need?

[Ruffus]

Good to read you're happy with your implant👍👍
Dr.Pulleys are a gamble supposed to last longer with less wear and tear.

For competition, IMHO, rollers of any brand but light enough to accellerate up to your mentioned 80 kmh perform best. For longevity take squares.