S&S Cycle Big Bore Kit for Milwaukee-Eight Overview

The S&S Cycle Big Bore Kits are designed to increase the displacement of your motorcycle without all of the guesswork, they’ll come with all the gaskets that you need. These big bore kits are made in a variety of sizes so you can pair it with your performance goals!

[jeremybishop]

Most riders of the M8's dont realize the power thats available in keeping the 114". I had planned to go big bore since I bought me 2022 street glide special new in December. However, I did a stage 2 kit zippers kit on my stock 114" motor. Now I had a great tuner and bought the right parts to make a great combination. I made 128hp/129tq to wheels from a 114" for about 4600$ Parts list as follows. Zippers stage 2 kit with their 472 cam, Sawicki 2-1 full stainless exhaust, screaming eagle 64mm throttle body and matching intake, bigger injectors, screaming eagle ventilator air cleaner and power vision tuner. I have power everywhere. I'm @ 129tq @ 2700rpm and stay over 120tq till 5200rpm. I make 100hp @ 4200rpm and 128hp @ 5200rpm and carries 128hp over 6200rpm. Bike rides stock at any rpm and only is nasty when I want it to be. 1st thru 3rd get its pulling front wheel off the ground and great wheelies in 1st. Im actually reconsidering going big bore because i only wanted 140 to 150hp but hard to justify spending extra 6 or 7k for 10 to 20 more hp. Hope this helps someone out looking for real data

[detroitharleyscene]

Just did the S&S 129 kit with the S&S 550c and I got to say it was worth every penny!

[joaomauriciobasiledesouza]

My only concern about installing those big bore kits is the stock m8 crank, if they are twisting with the stock cylinders, with stock power and torque, how can they handle this kits? Can we trust the stock flywheels or all those stories about crazy runouts are just myths?

[andrewvickers]

Thanks for the info re cast iron sleeves over the new ones

[RickyG]

From what I understand, if you do the new S&S 132" kit, but add a 4-5/8"stroker flywheel, it can be a 136" motor, amazing for no case boring

[holmchristiandiercks]

Original head fits? How about the screaming eagle cnc portet head? No manifold changes needed?

[timnevitt]

if i put on a big bore 128 do i need a bigger throttle body or just bigger injectors

[midwestprince]

Fuel moti offers a 132ci bolt on kití🤔

[corevi]

107 M8 info please if I bored Standard genuine HD 117 cylinders to 119 spec and used pistons from the M8 SE 107 to 119 kit would that work on the 107 shorter stroke bottom end ? is it the cylinders that are different lengths ( Hight ) or is it the pistons .