Takegawa 143 Big Bore Kit for the 2019 Honda Monkey

Installation of the Takegawa 143cc big bore kit on my 2019 Honda Monkey. The install was very easy; I'd say the cam install was about the same level of difficulty, just more work since so many pieces needed to come off first. I need to put on a couple hundred miles before I really start beating on it and get it dynoed, but everything seems good to go after the easy install.

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[_PEDRO]

Jesus, this bike is a Master piece!

Keep it up my friend, greetings from Brazil.

[hotrod]

Awesome! Looking forward to after break-in to see the performance difference.

[NotMe-stqc]

Always check the end gap of the ring inside the cylinder before installing them on the piston. You should be able to check this with a feeler gauge. There should be at least .0035” of gap x inches of cylinder diameter. With this bore size that requires a minimum of .008” of gap to avoid over expansion of the ring in the cylinder. There has to be a gap to allow for expansion. Failure to gap will cause the rings to seize in the cylinder. There is a tolerance on the gap. I would estimate ideal to be between .008-.015” of gap. Too big a gap and you will get increased crankcase pressure from blow by and increased oil consumption. Also install lubricated rings on piston. Also lubricate wrist pin and wrist pin bushing. Verify circlip that holds wrist pin in is firmly seated in groove inside piston. Increased bore also requires the replacement of the stock fuel injector with the injector for the 150cc Honda engine, Honda part# 16450-J36-K01. It’s a plug n play part that will make use of the increased bore and slight increase in compression afforded from the flat top piston in the big bore kit vs the sunken dome piston from the stock setup. Failure to change the stock fuel injector will result in an overly lean mixture that the ECU cannot compensate for. In essence you will seize the piston.

[apio]

Can't wait for an update, great video.

[dohc_vtec_dj]

Just for future reference. The pin that holds the piston to the connecting rod is called a “wrist pin”

[CracowGo]

This flat circle on the top of original piston is designed to reduce vibration during operation. It is apparent that the replacement does not have this, the original parts, however, are a different quality.

[stephensierchio]

Thanks! I have a CT 125 Trail 2021 model. Of course I want to improve without over stressing motor. I want to do a lot of riding via back roads this summer.

[catsbyondrepair]

Note you have to have the oil cooler for these big bore kits otherwise it will shit the piston and bore.

[TeamDNFracing]

What you keep calling the connecting rod is a wrist pin. The connecting rod is the rod from the crankshaft to the wrist pin. Not trying to be a jerk, but I thought you might want to know

[grantswiseman]

Which stand is that? And do you need special pegs for it to work with the monkey?

[Team-Fraser]

Very informative video thanks! Out of interest why did you go for the 143 over the 181? @eastcoastish

[endlesssummerfamily]

Watsup? What happened? I was thinking about the 143, but looks like yours may have failed. Did a ring fail? Piston looks a little chewed in the pic you posted today.

[codyfinchum]

Js but the rod you removed out of the piston isn't the connecting Rod it called the wrist pin great video other wise

[khangduong]

Không cần thay họng xăng vs kim phun vs ecu ư

[stevensalins]

Great job, please let us know how it runs compared to 125cc as soon as you get it all broken in. I really want this for my 2020 Monkey!

[kwameg.]

How much faster is the bike after this install.. in general.. just an estimate ??

[chenteddy]

Do you install new ECU to control the map?

[HOPPOVERSION]

Forget that it gives me anxiety just watching it lol

[robertcowan]

IN ORDER FOR BIG BORE KIT TO PERFORM YOU ALSO NEED BIGGER VALVES, HEAD WORK, INCREASE FUEL AND SET TIMING TO MATCH NEW ENGINE CC, S. ITS A COMBINATION

[mobilgin]

Listen, if you are unhappy with a small bike and don't appreciate the work of Honda engineering -just buy a bigger bike.