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Discussion Starter · #1 ·
hey guys! hope everyone in north america is enjoying their winter aha =p,

so my bikes got a full exhaust system twobros tarmac, and i will be adding the K&N filter when the weather gets nicer, but my question is, do i need a juice box? ive read on other forums that since the cb300f is fuel injected and has an o2 sensor, the bike will adjust for it, then others are saying you need a juice box? what is everyones opinion, or knowledge on the subject




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I've heard a slip on is just fine, but the config you're running you probably are better off running it with a power commander module, as your fuel figures may be outside of what's mapped in the EFI system.

Still, if you're running a bit lean, and aren't going all out, it shouldn't be a problem.
BTW, nice bike. I loved to have a white one as well!
 

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hey guys! hope everyone in north america is enjoying their winter aha =p,

so my bikes got a full exhaust system twobros tarmac, and i will be adding the K&N filter when the weather gets nicer, but my question is, do i need a juice box? ive read on other forums that since the cb300f is fuel injected and has an o2 sensor, the bike will adjust for it, then others are saying you need a juice box? what is everyones opinion, or knowledge on the subject




enjoy some pictures
Zac... read through this thread. Poster has a full new exhaust system and pretty well everything in the thread can be applied to you system..

http://www.cbr300forum.com/forum/parts-accessories/12937-danmoto-carbon-gp-full-exhaust.html
 
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Well I'm guessing your bikes running fine with the TwoBros Zac as you don't say otherwise, so there's your answer.
I've fitted slip-on's to both 250R & 300R with K&N filter and experienced no running issues from either.
You would only fit a juice box if you were chasing more power, but I would expect your gains to be be small in comparison to your investment.
 

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Hey Zac,

I installed the Tarmac Full System with a Power Commander PCFC. I have been in contact with Two Bros to try to convince them to get a Tarmac System to the boys at Dynojet so they can map the pcfc with the exhaust. At the moment they have suggested I just increase the high range setting to +5% which I did and I also added +2% to mid range. The difference is very noticeable with excellent throttle response. I also have a K&N filter. When you flog the bike the Tarmac exhaust sounds awesome!!

Cheers
 

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Discussion Starter · #6 ·
Hey Zac,

I installed the Tarmac Full System with a Power Commander PCFC. I have been in contact with Two Bros to try to convince them to get a Tarmac System to the boys at Dynojet so they can map the pcfc with the exhaust. At the moment they have suggested I just increase the high range setting to +5% which I did and I also added +2% to mid range. The difference is very noticeable with excellent throttle response. I also have a K&N filter. When you flog the bike the Tarmac exhaust sounds awesome!!

Cheers

thats an awesome reply! so are all the other ones! thanks everyone, i will now look for a juice box aha,
 

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My 300F is running a stock header with Two Brothers Tarmac. My air filter and mapping is stock. I do get significant snap-crackle-pop when easing off the throttle but with the throttle full-off, it just has a nice"dirt bike" sound and really good brakeless speed-scrubbing.
My questions are: 1) Have I caused the engine to run too lean (or does the fuel injection compensate for the pipe? and 2) is there additional baffle available for the Tarmac?
 

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My 300F is running a stock header with Two Brothers Tarmac. My air filter and mapping is stock. I do get significant snap-crackle-pop when easing off the throttle but with the throttle full-off, it just has a nice"dirt bike" sound and really good brakeless speed-scrubbing.
My questions are: 1) Have I caused the engine to run too lean (or does the fuel injection compensate for the pipe? and 2) is there additional baffle available for the Tarmac?
Yes it certainly sounds that way if you are popping on deceleration. Seems to be a fault that appears with some aftermarket systems once you lose the amount of back pressure the OEM system creates. My guess is the ECU isn't or cant compensate enough for the flow characteristics of your pipe, but then Zac never mentioned it and he has the same pipe so who knows...
 

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i will now look for a juice box aha,
Two Brothers no longer supply the Juicebox Pro, because it would appear that Dynojet have purchased the design and patent. If you compare the PCFC and the JuiceBox Pro they are identical as is the software and instructions. Dynojet have just plastered there name all over everthing :)

Now the problem is finding a unit in OZ or NZ..Mine came through Revzilla in Las Vagas.

There was a guy local to where I live that was selling them on his website $150 cheaper than anyone else I could find, when I called him to ask about shipping times he decided to increase the price after I hung up the phone, what a Tool.
 

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300F is running a stock header with Two Brothers Tarmac. My air filter and mapping is stock. I do get significant snap-crackle-pop when easing off the throttle
I had the deceleration pop before adding the Fuel Controller. As I understand, the popping is caused by unburnt fuel deposits being ignited by the exhaust gases. But I'm only going by what the internet is telling me, so it's gotta be right!
 

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I had the deceleration pop before adding the Fuel Controller. As I understand, the popping is caused by unburnt fuel deposits being ignited by the exhaust gases. But I'm only going by what the internet is telling me, so it's gotta be right!
Correct and because a lean running engine has a higher exhaust gas temperature it ignites more readily. What I'm not sure about is just why the lesser back pressure of an aftermarket system makes an fuel injected bike with an ECU run lean?
 

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All Motorcycles have that 'pop' on decel even with stock mufflers. Thing is the stock mufflers muffle the sound so much you can't really hear it until you open it up with a full racing exhaust. It is not necessarily a 'bad' thing to have some pop/crackle. If you are having loud backfires in between shifts etc that is a different thing and should be addressed. Mine always snap, crackle, pops as I roll to a stop in 2nd gear and the rpms get down to 3000-2000rpm's. It is actually a sound that every hotrodder strives for! lol
 

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You can easily put a plug in the Air Injection Solenoid tube and that will take care of a lot of the decel popping sounds. You will still get some but not as much. If you take off the left side mid panel. It is located just under the left side of the gas tank. 1 short 2 inch tube goes into the airbox then goes into a solenoid and on the other side a longer tube goes into the cylinder head cover. It mixes fresh O2 with the burnt exhaust gases. I bought a little 1/2 inch grey rubber cap from Home Depot and plugged the nipple on the airbox, then slid the tube back over the nipple. Problem solved.
 

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free flowing from less back pressure will allow more air into/through the system, this leans out the mix
Yes I can understand that scenario in a carburetor bike but you would think the ECU would compensate for the increased air flow/charge by upping the fueling rate. I noticed with the 300R they moved the O2 sensor out onto the header pipe. With the 250R it was inside the exhaust port of the cylinder head.

Late edit: Little did i know there was a thread already posted about the sensor location when I typed that.
 
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Yes I can understand that scenario in a carburetor bike but you would think the ECU would compensate for the increased air flow/charge by upping the fueling rate. I noticed with the 300R they moved the O2 sensor out onto the header pipe. With the 250R in was inside the exhaust port of the cylinder head.
The 300 ECU can adjust the a/f map within limitations. Not sure how many maps it has on it even. But when you go as far as a performance Air Filter and a fully open shorty exhaust the O2 sensor (being narrowband) doesn't read below/above a certain voltage and can only tell the ECU to adjust the mixture ever so much. I think a K&N and my DanMoto exhaust is right on the edge of being considered too lean. Anything more to increase airflow would definitely need a fuel re-map. I'm squeaking bye lol
 

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I had the deceleration pop before adding the Fuel Controller. As I understand, the popping is caused by unburnt fuel deposits being ignited by the exhaust gases. But I'm only going by what the internet is telling me, so it's gotta be right!

This is true. It is for environmental purposes as you said to burn off everything before it leaves the pipe.
 

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most people get the snap crackle pop when they are still partially holding open the throttle while engine braking. When you are engine braking the ecu automatically cuts off fuel until (in most cases) about 3000rpm (I'm gonna guess higher on the cbr300). then it puts a little fuel in so the vehicle dosent stall. This is the other time people get the noise. There may be other times but these are the main ones. As said previously this happens with any exhaust just a lot quieter with the stock one.
 
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Good grief, another thread that's degenerated into nerds and numbers. I can feel the will to live slowly slipping away......

;)

Who gives a rats where the noise comes from, all I care about is it sounds bloody cool. My XJR1300 used to do it and I confess I used to provoke it. Lovely!
 
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I can put out a theory;
It is possible, that the O2 sensor is running a lot cooler with an open exhaust than with the more restrictive, stock exhaust; as the hot air is faster exited.
This could possibly get O2 reading off, and make a bike run more lean...

Popping on deceleration happens even with the stock exhaust, especially when the throttle is blipped; but is much more contained by the muffler.
The Honda stock exhaust is a 2 chambers exhaust (almost like 2 exhausts in one cylinder) , so it doesn't allow you to hear much of the popping.

I would try wrapping the O2 area with some exhaust wrapping around the O2 sensor area, to see if the insulation will increase the O2 sensor temperature, and thus affect the O2 readout; but I haven't verified if it would work.
 
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