HONDA CT125 Big Bore Kit

[m in sc]

the thai ones from everything ive seen (maybe its changed in 22/) use the old grom style to the left. RH is the ecm style out of a US trail. oddly, my wifes supercub uses the old style as well, its a 21. so even the piggybacks and 'open' ecms that were compatible on the old ones wont work on (at least my) trail, a 21 us model. I took this pic, fyi, not a web image.

 

[dmonkey]

At the least the PGM-FI units vary in part number by region. Not unique to these bikes or Hondas. Different countries/regions have different emissions standards and fuel availability that are accounted for with different programming.

Elsewhere on this forum it was observed that early production models have an older physical plug type as well, it changed for both USA and Thai models. Those changes are usually noted in the parts fiche if you can find a current USA version of it.

 

[m in sc]

its on partzilla.

 

[dmonkey]

its on partzilla.

I looked on PartZilla and didn't notice any "superseded" notes there for parts that have been revised since production. In the print parts catalog there is another part to the page, not shown on PartZilla, that notes the region code for parts with regional differences, as well as what serial number a part was changed at if it was prior to printing of the catalog.
Example:

 

[m in sc]

its obvious if you cross reference numbers or look at the actual diagrams. the us model trails -never- had the old style ecm. Mine was one of the 1st ones here, so it would never be a retrofit or superceded number as the wiring harness is also totally different. which really sucks. trust me, ive been down this road.

 

[SLO]

The bike was running rich until you put in the NGK #6, is that correct?

Yes

 

[Jitenshakun]

Does anyone have experience with the full 143 kits from SP Takegawa? Reading this thread, the Yuminashi and letting the stock ECU is an option, but a full kit is tempting.

 

[JPMcGraw]

I just put the full kit on (tuner, piston, jug, cam). 100miles so far no problems. 50mph is easy to get to and maintain at 1/4-1/2 throttle. Its cold so most of that 100miles was 25-30mph for 15-30min max.

Once it warms up ill give it the grocery getter stress test.

 

[AZ7000']

I just put the full kit on (tuner, piston, jug, cam). 100miles so far no problems. 50mph is easy to get to and maintain at 1/4-1/2 throttle. Its cold so most of that 100miles was 25-30mph for 15-30min max.

Once it warms up ill give it the grocery getter stress test.

Please do, other have done almost the same but improved air flow with pipe and intake. You still have the oem injector? I think the 150 inj is cheap

 

[m in sc]

i mean, with the injector, cam, and bbk, even w the stock muffler and intake 50-55 was never an issue. Im not willing to drop what they want for a controller on -this- bike. however, the full kit will probably get you what you want.. but you will need an exhaust to breathe right and probably an intake setup as well. possibly a throttle body. its a slippery slope, but, Im not going to discourage anyone from doing it either as i did it on the grom and other bikes. really want it to breathe? get a 4v head. then shit gets real fun.

 

[Jitenshakun]

I just put the full kit on (tuner, piston, jug, cam). 100miles so far no problems. 50mph is easy to get to and maintain at 1/4-1/2 throttle. Its cold so most of that 100miles was 25-30mph for 15-30min max.

Once it warms up ill give it the grocery getter stress test.

Which brand did you go with?

 

[QuantiQualification]

Greetings folks. Currently have a new 2022 Honda Trail 125 U.S.A. Spec version. I have an incoming SP TAKEGAWA Hyper e-Stage Bore Up Kit 143cc Part Number 01-05-0641 (Includes 143cc piston and cylinder, Sports Camshaft (N-15), FI-CON TYPE-e injection controller (plug & play), spark plug, and Big Throttle Body Kit 28mm diameter), a SP TAKEGAWA Sports Exhaust, Stock Look Part Number 04-02-0359, a SP TAKEGAWA Crankshaft Support Adapter Part Number 01-10-0145, and a SP TAKEGAWA Air Filter Kit Part Number 03-01-0035. These are all of the parts needed to produce around 13 hp @ 8600 rpm per SP TAKEGAWA's dyno curves for the Hyper e-Stage Bore Up Kit 143cc vs. 7.3 hp @ 5800 rpm stock. I have done some pretty rudimentary first order calculations using the dyno curves and it looks like if the bike originally could only hit 45-46 mph indicated (on the speedometer) in a headwind/slight hill, it will now be able to hit 60 mph indicated in that same circumstance. Similarly, if it could have done 51-52 mph indicated on the flats, after install it should hit an indicated 68 mph. These numbers seem highly optimistic to me. Would love your thoughts prior to the install and actual test.

 

[m in sc]

should be about right. don't be surprised if you see 70 when its all broken in. aside from obvious breathing issues,the big restrictor is the timing curve on the stock ecu, it neuters the motor very low in the rpm band. the controller will def cure it.

 

[AZ7000']

Greetings folks. Currently have a new 2022 Honda Trail 125 U.S.A. Spec version. I have an incoming SP TAKEGAWA Hyper e-Stage Bore Up Kit 143cc Part Number 01-05-0641 (Includes 143cc piston and cylinder, Sports Camshaft (N-15), FI-CON TYPE-e injection controller (plug & play), spark plug, and Big Throttle Body Kit 28mm diameter), a SP TAKEGAWA Sports Exhaust, Stock Look Part Number 04-02-0359, a SP TAKEGAWA Crankshaft Support Adapter Part Number 01-10-0145, and a SP TAKEGAWA Air Filter Kit Part Number 03-01-0035. These are all of the parts needed to produce around 13 hp @ 8600 rpm per SP TAKEGAWA's dyno curves for the Hyper e-Stage Bore Up Kit 143cc vs. 7.3 hp @ 5800 rpm stock. I have done some pretty rudimentary first order calculations using the dyno curves and it looks like if the bike originally could only hit 45-46 mph indicated (on the speedometer) in a headwind/slight hill, it will now be able to hit 60 mph indicated in that same circumstance. Similarly, if it could have done 51-52 mph indicated on the flats, after install it should hit an indicated 68 mph. These numbers seem highly optimistic to me. Would love your thoughts prior to the install and actual test.

So what was the total damage? (Cost) for informational purposes please…

about 1/2 the town is a really steep hill away, oem config is about 34mph before I crest the top. Would like to be able to climb the hills in town with the traffic flow. Thanks

 

[QuantiQualification]

So what was the total damage? (Cost) for informational purposes please…

about 1/2 the town is a really steep hill away, oem config is about 34mph before I crest the top. Would like to be able to climb the hills in town with the traffic flow. Thanks

$1651.14 with shipping included for the parts listed above + $4556.94 out the door for the Honda Trail 125 itself so total for bike and these upgrades is $6208.08. This is quite a bit less than I paid for a new TW200 a little over a year ago. Prefer the Trail to the TW.

Just for fun, I did a quick calculation on what your 34 mph would get to with my setup. I am assuming you are running in 3rd gear. If so, your top speed would be 44 mph in 3rd gear at 7000 rpm. If you were running 34 mph in 4th gear, your top speed would also be 44 mph which is interesting but at 5620 rpm. If you didn't use the air filter and used the stock box instead, 4th would get you an extra 1 mph to around 45. This all assumes steady state. I think you are bleeding off speed as you climb so your end speed would be a little + or - the value given.

To get a few more mph would require more torque lower in the rpm range so you are looking at 181cc with all of the associated problems with that kit such as an oil cooler, bigger injectors, etc.

 

[m in sc]

i can hit 52-53 top of 3rd with a 143. you don't need a 181 to do that. stock ecm/gearing as well. and yes im 100% thats accurate.

 

[QuantiQualification]

i can hit 52-53 top of 3rd with a 143. you don't need a 181 to do that. stock ecm/gearing as well. and yes im 100% thats accurate.

You are likely correct. Thank you for pointing this out. My calculations and power factors are looking only at headwinds and not hills. In other words, if the bike could only achieve 34 mph because of stout headwinds, then my calcs should be close. Since most of the speed loss in AZ7000's case is due to overcoming gravity, your speed could be better than stated. My model was built around the premise of a top end speed (mostly on the level or slight incline/decline). So, for those that are inclined (yes, this is a pun) and interested in riding the trail in stout headwinds but not up a steep hill ;-) . . . max power stock at 34 mph, 3rd gear is ~7.2hp. 44 mph in 3rd gear would then require 12 hp which my setup "should" achieve. 53 mph would require a massive 17.5 hp.

 

[m in sc]

i was talking about climbing a hill as well. i have to hit a few on the way to work, some pretty good ones. 4th gear is more difficult, of course, but i can maintain 50+ up a pretty good long hill as well. and im about 210 lbs with gear on. estimating calculations are one thing, real world is another. you'll see when you get it installed.

 

[JPMcGraw]

Please do, other have done almost the same but improved air flow with pipe and intake. You still have the oem injector? I think the 150 inj is cheap

I got a pod filter, 150 injector, and yoshi gp-magnum installed too

Which brand did you go with?

Takegawa

 

[AZ7000']

Thanks all, Thinner air also up here, even with my fi wr250 my butt dyno sees quite a difference whenI go to Phoenix. I know the fi helps vs the carbed bikes but they do talk about the power loss in supercross at both Denver and Salt Lake.