HONDA CT125 Big Bore Kit

[Samg7]

There is some confusion online about the injector labeled 5HT. Takagawa says its 140cc/min, but most people report it being 115cc/min.

Yuminashi even has a bit about it on their website:

The Takegawa injector flows less (based on social media info 115cc/min) compared to our genuine Keihin 5HT injector, which is strange in our opinion because Takegawa are also advertising their injector as a 5HT injector with a G-nozzle so it should be the same flow as our injector.We respect our Takegawa colleagues and we personally never tested the Takegawa injector, so if the social media info is correct, then we have no explanation for this difference.We from our side can only confirm that we are providing a genuine Keihin injector/product and that the flow of this injector is 155cc/minute at 3.2bar pressure.

 

[RustyRodder]

Now I need to check the injector I got- It was a no-name Ebay injector for a PCX. Wonder if I should just get the OE honda one.

 

[Samg7]

Quick check, let us know the code on it.

 

[RustyRodder]

Looks like.it only has a part number- 16450-k36-j01

 

[Samg7]

Looks like.it only has a part number- 16450-k36-j01

Can you verify the code printed on the actual injector?

 

[Happy Campa]

Looks like.it only has a part number- 16450-k36-j01

Is this your old injector or the one you ordered?

 

[RustyRodder]

Printed on the new one. No embossing or marks anywhere else

 

[SLO]

I'd put money on it helping. I just ordered a PCX150 injector as well. Now I need the cam and bore kit!

I would not go bigger than a 143cc bbk,as other components are not designed to handle the additional loading,as well as the heat developed,as well as the ECU not being compatible,as well as the suspension,ride characteristics of bike frame etc. I believe I would buy an XR 150,and the only mods would be a upgrade to the exhaust,a carb upgrade ( NIBBI ) and open the intake. Done,reliable,with the suspension better,as well as a 3 plus gallon tank for over 300 miles per tankful. If you want it reliable,adhere to the YUMINASHI recommendations for BBK on the HONDA TRAIL. You are talking oil coolers,upgraded this and that. If mine came from the dealer the way it runs now,I would have left it alone.

 

[Samg7]

Printed on the new one. No embossing or marks anywhere else

I do not believe that to be a genuine Honda part, but that doesn't mean it isn't an aftermarket equivalent.

I have a PCX150 injector coming into my Honda dealer this Friday, I will post a picture.
It is a genuine Honda part, I think the only PCX150 injector you can get straight from Honda in the US.

My Yuminashi PCX150 injector and the 170cc/min injector should be here the 30th, will post pictures off those as well.

 

[Happy Campa]

I would not go bigger than a 143cc bbk,as other components are not designed to handle the additional loading,as well as the heat developed,as well as the ECU not being compatible,as well as the suspension,ride characteristics of bike frame etc. I believe I would buy an XR 150,and the only mods would be a upgrade to the exhaust,a carb upgrade ( NIBBI ) and open the intake. Done,reliable,with the suspension better,as well as a 3 plus gallon tank for over 300 miles per tankful. If you want it reliable,adhere to the YUMINASHI recommendations for BBK on the HONDA TRAIL. You are talking oil coolers,upgraded this and that. If mine came from the dealer the way it runs now,I would have left it alone.

That may be wise for longevity. To start, I ordered an pcx150 injector and aftermarket camshaft. Each paycheck I'll build it incrementally.

 

[m in sc]

theres plenty of 164cc big bore kits running around on stock motors, its fine, can even go bigger, not a big deal, and can be very reliable. i had years on my grom motor w a 170 4v and i took it too far at the end, which was totally my fault. I spun it up past 11k and snapped the rod tuning the power commander, i knew better too, but that bike would also touch 100 mph, and did it for years. but on THIS bike in particular, you need to match the injector and fuel management to handle it. the efie will do it. the bike can handle it just fine, thats just speculation w no experience to back it up to say it wont. But yes, on this particular bike you def need a bigger injector to work right and absolutely need to give plenty of time for the ecm to learn. if you dont, it will go kaboom. I have literally thousands of mile now on my big bore kit, its fine.

 

[m in sc]

as a side note my 150 should be here soon, shipping on the 25th of next month.

 

[RustyRodder]

I do not believe that to be a genuine Honda part, but that doesn't mean it isn't an aftermarket equivalent.

I have a PCX150 injector coming into my Honda dealer this Friday, I will post a picture.
It is a genuine Honda part, I think the only PCX150 injector you can get straight from Honda in the US.

My Yuminashi PCX150 injector and the 170cc/min injector should be here the 30th, will post pictures off those as well.

Oh, its definately not- it was an Ebay special I picked up a while back, some no-name reproduction. But Upon consideration, Im not sure I trust it to be truely 140cc

 

[SLO]

That may be wise for longevity. To start, I ordered an pcx150 injector and aftermarket camshaft. Each paycheck I'll build it incrementally.

You will notice a difference ( BIG ) with just the 238 cam alone,without the bigger bore kit. Just make sure you line up cog on timing chain sprocket with cam when installing. Probably easier if you remove cam chain tension .I did not,and did not have lined up properly when I tightened . I made it about 15 miles. I could tell a difference before the tab on the sprocket snapped.

 

[RustyRodder]

What would you say the minimum supporting mods for a cam is?

 

[Happy Campa]

What would you say the minimum supporting mods for a cam is?

I'm not sure, but I ordered a PCX150/150 cc fuel injector to couple with the Clipping Point cam I ordered. Hopefully it'll all come in by this weekend. I'll let you know!

May 26th - The cam is in and it seems to be running fine. Time will tell.

 

[m in sc]

I tried the high compression 125 piston as well, and it helped a lot. tried the tb cam, which is more top-end oriented, a stock grom cam, and then the yuminashi cam. all of this with a decatted stock exhaust, all on a stock injector. I didnt feel the need for the larger injector until i went to a 143 and a larger exhaust system, but it can't really hurt as long as you keep it reasonable.
If you look at x92saabs posts on his bike, the HUGE injector he had, i sent it to him. thats primarily for 180cc+ motors, too much for the 164 hes running. so, be careful with going too big as the injector may not be able to trim down enough, or perform poorly if its too large. Theres value in know 'whats too much' as well.
Im running a genuine pcx150 injector, 143, 28mm throttle body, larger intake (not an open pod filter) w larger filter IN the airbox, and aftermarket exhaust and it handles it just fine. .02

 

[SLO]

What would you say the minimum supporting mods for a cam is?

None,except check what the valve clearance is. It might change,or change what it is currently. Check after running a minute or two, let cool off to room temp,check. The valve adjusting screws
will work,but while ordering the 238 cam,order some longer ones. I put the cam in before the big bore kit,and noticed big improvement right away. I did not line up slot in cam with timing chain sprocket
before tightening,and the tab on the timing chain sprocket snapped off after about 15 miles. Loosen the timing chain tension as I did not,and it should make it easier to put timing chain back in place.
I think the 143 cc bbk install was actually easier.

 

[SLO]

as a side note my 150 should be here soon, shipping on the 25th of next month.

Are you talking about a new bike? or mod to existing one. The US version of the XR 150 does not come with kick start. I would insist on it if I was ordering,and of course you would be told no,sorry. They make em every day,and I believe these are being built in MEXICO. Salespeople lie for a living.

 

[m in sc]

xr150l, new bike. I don't talk to salesmen for info, they don't know anything, lol. I tell the GM what I want and he puts my name on it for when it arrives. I could care less about a kickstarter on this bike TBH.

and you always check valve clearances dead cold on a non hydraulic lifter motor. .02