Big bore kit

[SLO]

Have about 330 miles on 143 cc big bore with cam. Bike absolutely sucks without it! I have about 3900 miles on it now,and actually enjoyed my ride today. I rode about 78 miles today in about 3 hours with lunch and snack break,and never had a car behind me.I can tell you about why ,and when to change front sprocket,and how sudden ,and drastic elevation change dictates what you do if riding with potential traffic,and what bike can,and will do.I was asked what it cost to upgrade earlier,and I over stated cost. I bought torque wrenches,valve adjust tools etc, but cost of big bore kit with cam upgrade was around $ 258 dollars delivered. You have to open exhaust,air flow in ,and change injector. Cost without tools was around,$ 750.00 bucks. The bike is a piece of shit,without doing this. Do not deprive yourself! YUMINASHI direct sales,I hope I spelled correctly.

 

[NT_Aussie]

Ive just taken delivery of a new Green Machine ( one of the very last sold in Australia,, havent even registered it yet, but will have that sorted in the coming days. Already have the Yuminashi 143BBK, 238Cam, 140cc Injector and 15T sprocket in a box and ready to install, Ive also purchased a set of fully adjustable rear shocks that arrived today, Just waiting for a bit of bar work to arrive and then the real fun will begin. There are a group of guys in ChaingMai Thailand that have been doing heaps of research and mods to the CT125's for about 2 years, I followed them intently before shelling out and actually purchasing the bike, I also purchased a GROM ECU that will remove the rev limiter but that will need a wiring mod so a bit of research ahead before adding that one to the mix. (ive got another cylinder head on order that I will port and polish so its all ready to go at the same time.) about all i need is a new exhaust with the 19mm header pipe and a SS cone intake pipe to complete the build.

 

[AZ7000']

Already have the Yuminashi 143BBK, 238Cam, 140cc Injector

Is this all that is needed if one would just want a little extra grunt? Does the pipe need to be opened and if so how would the 143BBK, cam and injector only work without a bigger pipe?

Thanks for any info

 

[m in sc]

you have the details on the wiring mod? az: i have had that setup for a while, it works well. I also have the eife but otherwise the same. the issue is the ecm for top speed.. if he can truly swap to a grom ECM, thats a game changer w out having to drop 700 bucks on a standalone ecu. Id like ot see the details on the wiring change to make it work.

 

[NT_Aussie]

Ive just taken delivery of a new Green Machine ( one of the very last sold in Australia,, havent even registered it yet, but will have that sorted in the coming days. Already have the Yuminashi 143BBK, 238Cam, 140cc Injector and 15T sprocket in a box and ready to install, Ive also purchased a set of fully adjustable rear shocks that arrived today, Just waiting for a bit of bar work to arrive and then the real fun will begin. There are a group of guys in ChaingMai Thailand that have been doing heaps of research and mods to the CT125's for about 2 years, I followed them intently before shelling out and actually purchasing the bike, I also purchased a GROM ECU that will remove the rev limiter but that will need a wiring mod so a bit of research ahead before adding that one to the mix. (ive got another cylinder head on order that I will port and polish so its all ready to go at the same time.) about all i need is a new exhaust with the 19mm header pipe and a SS cone intake pipe to complete the build.

Is this all that is needed if one would just want a little extra grunt? Does the pipe need to be opened and if so how would the 143BBK, cam and injector only work without a bigger pipe?

Thanks for any info

The 143BBK alone just adds lots of torque at the lower end... it needs the head ported to suit the 56mm piston, 19mm header and larger intake pipe, the ECU rewire & swap just removes the 7K rev limiter ( also need double valve springs if removing the rev limiter), Ill also run a 15T or 16T on the front but note: this will cause ABS errors unless you have the OPMID M1204 Odometer as it has the ability to change the rearing ratios ( this maybe possible to also do via a scan tool but I will not know until my OBD2-Honda 4 pin adapter arrives)

 

[NT_Aussie]

you have the details on the wiring mod? az: i have had that setup for a while, it works well. I also have the eife but otherwise the same. the issue is the ecm for top speed.. if he can truly swap to a grom ECM, thats a game changer w out having to drop 700 bucks on a standalone ecu. Id like ot see the details on the wiring change to make it work.

I also purchased a OBD2 to 4 pin Honda Cable adapter so I can see the live ECU data with my scan tool ( the Honda uses a basic OBD protocol and should be able to be read by most scan tools including the ECM327)

 

[AZ7000']

The 143BBK alone just adds lots of torque at the lower end... it needs the head ported to suit the 56mm piston, 19mm header and larger intake pipe

Sorry, a bit confused here…. I need head work with the bbk kit? I can’t just bolt on the kit?
Maybe this is a different kit then the ones I have seen

 

[m in sc]

yes you can bolt the kit on a stock head, its fine. A stock head can carry up to 164 kit, been there done it on my 1st gen grom, which had/has the same head. I went to a bigger valve head with that kit, and it was ported, and made -marginal- differences until i put the power commander on.
The big issue w the trail is the ecm and timing curve beyond the exhaust and injector. example: a stock '22 grom with a bigger injector, flashed ecm and exhaust can hit a legit 70 pretty easily with zero head work. Ive seen it 1st hand. beyond that, its intake time. My 1st gen grom dead nuts stock would hit 64 indicated/62 actual flatland riding. the cyl and head are the exact same as they have been since '14.

 

[SLO]

Ive just taken delivery of a new Green Machine ( one of the very last sold in Australia,, havent even registered it yet, but will have that sorted in the coming days. Already have the Yuminashi 143BBK, 238Cam, 140cc Injector and 15T sprocket in a box and ready to install, Ive also purchased a set of fully adjustable rear shocks that arrived today, Just waiting for a bit of bar work to arrive and then the real fun will begin. There are a group of guys in ChaingMai Thailand that have been doing heaps of research and mods to the CT125's for about 2 years, I followed them intently before shelling out and actually purchasing the bike, I also purchased a GROM ECU that will remove the rev limiter but that will need a wiring mod so a bit of research ahead before adding that one to the mix. (ive got another cylinder head on order that I will port and polish so its all ready to go at the same time.) about all i need is a new exhaust with the 19mm header pipe and a SS cone intake pipe to complete the build.

Unless you are on flat ground ,The 14 tooth is the best it can handle. The 13 tooth works better with or without the big bore and other mods in changing elevation ( steep hills ) since the bike will not rev up enough beyond third gear to facilitate sufficient speed. The drastic changes in elevation may play a big part in it ,due to the ECU not having constant conditions on which to correct fuel ratio as fast as conditions change. Keep it simple. You will go faster with a 13 tooth, but you are revving the shit out of it. So what, it can handle it. But if you are going \to ride faster than 50 mph for any period of time,get another bike for the stable. Life is short !

 

[SLO]

Is this all that is needed if one would just want a little extra grunt? Does the pipe need to be opened and if so how would the 143BBK, cam and injector only work without a bigger pipe?

Thanks for any info

You have to open intake and exhaust. Back pressure is not good. It is an air pump, in , out, the power is in the O2, the fuel enables us to access it. I am sure there
is something better than decayed ,pressurized organic matter ( once living things ), but those in control decide what we are allowed to possess.

 

[NT_Aussie]

Ok so my 143bbk and 238 cam turned up but in the meanwhile i've been digging through the Thai racing websites, so its going to sit on the shelf with the original cylinder and head for rainy day spares if needed

I decided that its only money and he who dies with the most toys wins.... so out with the visa and i've purchased these 2 beast sets to go into my 21 CT125 ,
I purchased this in 57MM so its closer to 150cc since the Sleve was much thinker than tthe 56mm ... with conversion the engine kit cost 13,499 THB plus DHL @ 13,000THB ( its 18KG) ($1100aus at todays exchange rate)... the ECU is 4,150 THB plus shipping but its BT and all map programming can be controlled via our mobile, The crank is balanced and the head comes with 28/24 valves, heaver springs and has been ported ... I most likely wont get this installed until im home in early February.... While i'm in Thai will try to purchase the left side engine covers in Black so it all matches...

Hopefully the engine kit arrives before i depart for thai so I can check to see if i need any extra gaskets etc.

Should be a weapon on the streets when im finished... Ive had the thai bikes round me up on the freeways in Bangkok while im drivine at 100 like im standing still, so i'm interested to see what this transplant offers

here are the links if anyone is interested.... https://www.facebook.com/Hispeedglobal/
https://ecu-shop.com/products/full-stand-next/ ... you need the ECU for the HONDA WAVE 125LED 2020+