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Discussion Starter #1
Hi guys, had an interesting learning experience today on my way back from the DMV. The bike ran great on the 35 mile run to the DMV and about 20 miles back. I stopped for fuel on the way back and while filling up I cranked my bars full left. I thought nothing of it at the time, but it was important, as I would find out later.

Finished fueling up, bike starts normally. I pull out on to the road, and as I shift into fourth gear doing about 40mph, it starts bucking a little. By the time I got it to 45 it was really coughing and bucking. Would not make 50mph.

I pulled over, and it idled normally and revved up just fine. Back on the road- same problem!
So now I'm thinking the gas station has water in the fuel (it's been raining a lot here lately) and I'm going to have to drain a full and heavy tank of fuel.

Well, I nursed it home down the county roads and pulled into my garage dreading the tank draining I anticipated. I got off, removed my helmet, looked the bike over and -there it was! 5 seconds later it was fixed and a subsequent test ride through the gears showed no problems.

Anyone care to guess what it was? Here is a hint- it has to do with something that was a very innovative feature at the time on our machines. It was not bad fuel, btw.

Regards,
M.R.
 

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Discussion Starter #2
No Guesses? Ok, I'll narrow it down some- that which makes us faster can make us slower if its not connected. If it IS connected, the faster you go, the FASTER you go. If it's not connected, the faster you go the worse it runs...

And it has to do with air...

Regards,
M.R.
 

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Discussion Starter #4
You got it Viktor92! That's exactly it!
Except I didn't forget to connect, the tube came loose when I turned the bars to full lock! Luckily there is just enough room for my hand to get through the gap. Five seconds later- VROOM! Power all through the range.

It really is a worthwhile experiment to run when you have a few spare minutes. The difference is startling, even at such a low speed!


Regards,
M.R.
 

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Ha ha, I've experienced exactly that two weeks ago, but I forgot to connect the hose...
It's incredible the influence of that hose, I couldn't accelerate past 4k rpm in motion.
 

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It's that little hose which connects to the little 'pitot' which peeks-out from just behind the air-intakes, and runs to the carbs, where it separates to two-hoses, which pressurizes the...feul-bowls ? carb-floats ? I never truly understood what it does, but always assumed that if Kawasaki engineers saw-fit to include it, then it's critical for proper carburetion...even on the earlier C-models...especially-so, given that we only have ONE intake, compared to the D-models...
 

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Thanks for sharing! This just happened to me, but after a BUNCH of work (carb cleaning and bigger jets, new plugs, new exhaust). It ran great when I bench tested in the garage, but when I took it out for a ride it would sputter and fall on its face around 3-4k. I was sad because it seemed to run great in the garage and I thought everything was buttoned down tight. I googled a bit under the assumption that the carb rebuild was messed up even though I felt like I triple checked everything...lol.

Then I found this thread and sure enough, I missed that pipe! I then had a fantastic ride after reconnecting it. Thankfully I left the top cover fairing off so I could see the hose sitting there...doh!

ZZR1200 exhaust with shorties put a big smile on my face when it ran right. :D

This should be a sticky or something - VERY common issues with your ZX11.

Thanks again!!
 

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Thats another + reason why Im running dual lines, other then it runs better. Easy to possibly miss one hose, but TWO hanging there?
 

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You got it Viktor92! That's exactly it!
Except I didn't forget to connect, the tube came loose when I turned the bars to full lock! Luckily there is just enough room for my hand to get through the gap. Five seconds later- VROOM! Power all through the range.

It really is a worthwhile experiment to run when you have a few spare minutes. The difference is startling, even at such a low speed!


Regards,
M.R.

Interesting !!??

So maybe this is a dumb question.... but Ram air is only effective when I am moving. If I am sitting in my garage and I am tuning my bike, How do you guarantee the bike is running it's best?

it's a bit confusing if I am trying to tune carb for instance and all tubes are hooked up... BUT the airbox is off so I can freely see the carbs.... I get everything running well. I can put it back together and run it down the road and it runs WORSE?
...I have a lot to learn !

Todd
 

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You got it Viktor92! That's exactly it!
Except I didn't forget to connect, the tube came loose when I turned the bars to full lock! Luckily there is just enough room for my hand to get through the gap. Five seconds later- VROOM! Power all through the range.

It really is a worthwhile experiment to run when you have a few spare minutes. The difference is startling, even at such a low speed!


Regards,
M.R.

I am not positive what you are talking about ... but I need to research this .... this sounds a bit like my prob...

Todd
 

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Discussion Starter #11
Hi everyone, I haven't been in the forum for a long time because (insert lame, but true, excuses here) and just ran across this post again. I'm glad my experience was able to help some of you.

To sumarize: the small tubes that run inside the larger air intakes are to equalize the pressure in the float bowls to what is available at the carb mouth. Otherwise the higher pressure at the carb inlet will push the fuel back down the jets, causing a lean condition like an empty fuel bowl.

And yes, even at a fairly low speed (occurred at about 45mph for me) the effect is very pronounced.
Try this: put on an open-face helmet, accelerate to 45mph and open your mouth. That's what the carbs feel, and that's what is pushing the fuel back down into the bowl (or more accurately preventing it from being drawn up through the jets.) if the equalizer tubes are not connected.

As for running without the airbox installed, it will never run the same as with it installed. The air box helps (among other things) smooth the air flow with the shaped velocity stacks inside. Without it, turbulence will disrupt airflow and consequently fuel flow giving you odd running. The CV diaphraghms don't like turbulent air flow and will flutter unpredictably giving you poor runnings.
If you tune that out with adjustments then re-install the air box, it will run badly. That's why pod filters can be such a headache- the engine is engineered and designed and tested to run properly with the air box installed.

If you are having problems, usually it is best to return everything to the recommended factory base line and proceed from there. Then make ONE change, test, record observations, repeat.

Nsxdude82, there is no way to tell for certain if that is your problem via the interwebs, but I hope it is since it is a simple fix.

Regards,
M.R.
 
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