Cbr125 throttle body on MSX 125
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You going to keep us waiting again??
lol:encouragement:
I hope you did not revert to this as the Apitec controller was a bust!
lol:encouragement:
I hope you did not revert to this as the Apitec controller was a bust!
Next i identified the wires on the CBR throttle body. These are not plug and play and the wires are different colors on the grom. On the CBR TB Honda built the IAC sensor into the same assembly as the TPS, so it was just a matter of figuring out which of the 5 wires were for the TPS. One is the VCC the other is ground and the third is the signal out from the Pot. I hooked up the VCC to a 5v power source and verified the correct output wire with my volt meter. The output was spot on in comparison to the MSX. I next took resistance reading of the injector which was also within the ohm reading specs as outlined in the manual.
The msx fuel line hooks up directly to the cbr TB and I then bolted on the throttle body. Using a CBR wiring harness i bought from Ebay I cut off the connectors for the sensors and stuck the wires into the corresponding pins. I then hit the start button and it started right up. It is running really rich so Ill need to adjust the controller tomorrow. The great thing is It does start and run, now I just need to tweak the fuel adjustments.
The CBR throttle body has a few differences that I believe may make it a viable upgrade option. First it is larger, the outlet is almost 28mm as apposed to the msx TB which has a 22mm outlet. Second is the injector, the cbr has a larger capacity injector which will make it unnecessary to purchase the light bore injector from Yuminashi when installing a big bore kit.
The CBR throttle body has a few differences that I believe may make it a viable upgrade option. First it is larger, the outlet is almost 28mm as apposed to the msx TB which has a 22mm outlet. Second is the injector, the cbr has a larger capacity injector which will make it unnecessary to purchase the light bore injector from Yuminashi when installing a big bore kit.
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Once again, your efforts are greatly appreciated by everyone here!
Do we know if the Yuminashii SX30 head will have a 28mm intake port?
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Also, I will forward your comments about the IOS app to the Admin team.
Here is the removal of the MSX Throttle body
Measurement of the stock TB outlet (22mm)
Measurement of the CBR125 TB outlet (about 28mm)
CBR 125 TB mounted to MSX engine
Keep in mind this is just the rough testing phase, it is not pretty or final. There is still plenty of work to do to get the throttle cable to work properly and angle the intake to make room for a filter. It was just to prove the engine will run with this TB.
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1,660 Posts
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1,660 Posts
Im searching for a used CBR125 TB on ebay - what is the complete TB to look for? Just the TB and the TPS sensor? I guess the injector itself is a must, and the harness would be helpful. What else?
I just got a complete CBR 125 TB with all the sensors and injector already on it. Most of the used ones will probably have them on. I was patient and was able to get them really cheap. I paid 14 euro for the harness and 20 pounds for the TB. UK ebay has lots of them and German ebay as well. Just make sure you get a '08 and up harness. The older CBRs were carbureted.
Heres a link for the boot, i accidentally bought it for another project and it worked perfect for this TB, I got lucky
http://tboltusa.com/store/26mm-tb-intake-replacement-boot-p-117.html
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1,660 Posts
You missed the point entirely.
Modding isn't for everyone, but its not about the money, its about seeing what is possible and to me that is about as fun as riding. So continue buying your bolt on parts and post another tidy tail or exhaust install thread. I for one get tired of reading the same shit 10,000 times. I want to read about people doing engine mods and posting their results, because good or bad, maybe I learn something. Fabricating parts from scratch is where my interest lies. Don't get me wrong i have bolt on stuff too, and if it gets air in or out of the engine faster i may buy it. Im into performance and much less aesthetics because contrary to popular belief stickers don't make you go any faster. I have faster bikes, but i want to see how far I can push this little engine and experiment with the EFI system along the way, i believe its a great platform to begin with.
Sent from my iPad using HondaGrom.net
Sent from my iPad using HondaGrom.net
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What? You mean my HRC sticker does not make me go faster? I suppose your going to tell me that my Ohlins sticker wont improve my forks either.....
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111 Posts
Have to agree with Shapeshifter on this one. The only advantage of a carb is familiarity. Of the minority who actually know their way around carb tuning, it's easier and cheaper to deal with, especially on a non-stock tune. The disadvantages are...EVERYTHING ELSE.
The only reason why a carb would "make more power" than EFI, is if the EFI setup isn't done correctly. Other than tuning runner length, to change the power peak, no one ever "made" power with induction system parts. The engine makes power, by moving air. A sub-optimal induction system restricts breathing and power.
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Nice!
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