Yuminashi 238 cam

[Jferjr]

Im interested to get one of those in my otherwise bone stock bike along with a PCX 150 injector. Anyone have any experience with it?

 

[m in sc]

i have on in my 143. its really good.
kind of the 'rv' cam of 125 motors.

 

[Jferjr]

Do you experience any cutouts? Like of it wants more fuel when going uphill. I live in Pennsylvania and it's all hills here.

 

[m in sc]

me? no. ive had mine in the mts of nc, zero issues.

 

[Jferjr]

I see you did an adjustable cam gear on it too. Did you play with the timing of it?

 

[m in sc]

its advanced 2 degrees or so. you cant get any real top end out of this motor w out a standalone ecm, so i did that to get a bit more out of the mid/bottom rpm. BUT, the gear is way heartier than the stock one so more than anything, its a stronger part.. by far a better design.

 

[Jferjr]

Im waiting for a dynojet tuner. Then ill big bore it and play around with more things. But I think ill get this cam. It was either this or a 5 speed transmission and that I would have to split the cases for.

 

[m in sc]

they arent offering one yet, im sure you know that though. just fyi. also.. i jus tput in a PC6 in my cb1100, and let me tell you, the dynojet guys got hammered by the epa, you can't now adjust more then 15% fuel trims. it was compared to the PCV, a joke. Be warned, the new items are pretty weak. I'll never buy a PC again, and ive been using them for years.

 

[Jferjr]

How about the aracer fuel tuner? Any good for modding?

 

[Thepen]

A racer is great, but only in conjunction with the af2 module, obviously, far better than the pcv I have in my 701

 

[m in sc]

^ this. Im not ready to drop 700 on a controller for the trail yet. but prob will eventually unless somebody offers an ecu reflash.. eventually.

 

[Jferjr]

I wonder what dropping a much larger injector on the stock map will do. There are tons of them on the yuminashi site. But I think ill just do the cam and an exhaust swap.

 

[Thepen]

@m in sc covered this in a thread. He pioneered the ct 125 yuminashi 143 bbk + pcx 150 injector + efie mod. Swapping the injector for a bigger one on the 143 doesn't necessarily give you better power, its just to trick the ecu into not running too lean for that bigger bore. Because the ecu doesn't really know that you added a bigger bore, nor does it know it has a bigger injector, so it injects just that much more fuel so the 143 kit doesn't totally lean out. Makes the small adjustments for the ecu easier. The efie mod is just to bring the temps down and afr's down to 12.5-13.5 to be on the safe side.

 

[m in sc]

it will keep the duty cycle down in your application. the computer will still aim for the same afr. it will correct it so basically, not much overall. I run a 150 injector but also run a eife to fool the computer into thinking its running leaner than target afr its programmed to run at. you run too big an injector, it will run like crap though. i went thru this with the 170 4v setup i had on my grom, was running a pretty huge injector and 1t 10.5 k would be at 80% duty cycle, which to me is good. I ran a 150 injector on the 2v 164 setup i had on before that, and it was fine as well. so, unless you plan n going to a 4v setup or a 182 setup, or a much larger throttle body, the 150 injector will be ok and probably more than you will ever need, especially on a stock bore motor. .02.

 

[Jferjr]

No 4v for this bike. My goals are a cam, either a 164 or a 170 bbk, and exhaust. Maybe a 5 speed. But I would like to keep the intake pretty untouched as I like the snorkel to it. I dont necessary need to modify this bike but this is what I love to do.

 

[m in sc]

then plan on an aracer setup like pen has. 143 is small enough i could get away with what i did.
.02

 

[Samg7]

So has anyone ran the 238 cam with the PCX150 injector on the stock piston?

I am thinking about running this setup before installing my yuminashi 143 just to see what effect the 238 cam has.

But definitely need to install the PCX injector along with the cam... right?

 

[m in sc]

i did. it was pretty good. ran it with a high compression 125 as well from doebeck? def better than stock. not leaps and bounds but noticeable.

 

[RustyRodder]

M, did you do the efie before the cam?

 

[m in sc]

yes. is it necessary for just the cam? probably not. one of the 1st things I did on the bike was make a bigger headpipe and decat it. i eventually changed the exhaust out completely though. when i did the original pipe mods, i added the efie. Originally i had a TB cam in it, and was much higher rpm oriented, which really did me no favors.