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post #1 of 29 (permalink) Old 08-21-2006, 08:43 PM Thread Starter
 
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Is this normal?

This is my first fuel injected bike so I need to know if this is normal. When in neutral or when the bike is clutched and I quickly go to full throttle the bike kinda goes blah for a second then immedietly revs to 10,000. My question is the blah part where it seems bogged down. Is that something wrong or that's just what happens?
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post #2 of 29 (permalink) Old 08-21-2006, 10:08 PM
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Does it only do it when you are free-revving the engine or does it do it under load as well?

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post #3 of 29 (permalink) Old 08-22-2006, 01:51 AM Thread Starter
 
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Well rarely do i put the hammer down from a dead stop but I think it does it in both situations. The instantaneous intense power isn't there when i do a quick open throttle... but if I slow it down a bit it's all there.
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post #4 of 29 (permalink) Old 08-22-2006, 01:58 AM
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IMO its normal to have a very small blah.

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post #5 of 29 (permalink) Old 08-22-2006, 04:08 AM
 
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There shouldn't be much hesitation if any. The only time I get hesitation on my bike is when the RPMs are too low. If you are "gunning" it from Idle RPM's under load then its pretty normal. But free reving it should be nearly instantly screamin. maybe just a touch of a "blah" but very little. I may be way off here but my bike was running pretty crappy, lots of hesitation and lack of power and I threw some Injector cleaner in it and now she runs like brand new. Just a thought.
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post #6 of 29 (permalink) Old 08-22-2006, 06:29 PM Thread Starter
 
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I thought injector cleaner was a scam. I heard they already put that stuff in regular gasoline.
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post #7 of 29 (permalink) Old 08-22-2006, 06:32 PM
 
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In quantities to maintain a new engine, yes. But if you have a bike or other toy that sits for periods of time. (he just bought his) And you don't put stabil or something in it. (who knows what the previous owner did) The bad gas can gum up the injectors, and while the additives in gasoline are enough for maintenance, they aren't in high enough concentrations to clean it out once it is gummed up with deposits.
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post #8 of 29 (permalink) Old 08-22-2006, 06:55 PM
 
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You've heard that carbs have to be synchronized, but did you know that EFI throttle bodies have to be synched too? Even uses the same tools as carb synching. I would add the injector cleaner and then synch the EFI.
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post #9 of 29 (permalink) Old 08-22-2006, 10:31 PM
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Well, I'm not a real Honda guy but I can tell you that just about all of the fuel injected bikes use some sort of secondary throttle control. This is used to help keep the intake velocity up when the throttle is opened quickly. Many "racers" like to disable and/or remove these systems in an effort to gain more peak horsepower. The downside is that the engine becomes very sensitive to throttle inputs and requires the rider to be very smooth.

I would check to see if your bike has such a system and if it is functioning properly.

Just a thought,
Larry

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post #10 of 29 (permalink) Old 08-23-2006, 09:18 AM
 
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Yo!! Larry!!! great post!!! Rep points!!!
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post #11 of 29 (permalink) Old 08-23-2006, 12:50 PM
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Try doing the quick throttle in a higher gear... and get back with us.




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post #12 of 29 (permalink) Old 08-23-2006, 01:01 PM
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My FI bike has no bog whatsoever. The throttle response is quick and responsive. I would take it in to have it looked at.
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post #13 of 29 (permalink) Old 08-23-2006, 01:37 PM
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Quote:
Originally Posted by GR_Z750s_rider View Post
My FI bike has no bog whatsoever. The throttle response is quick and responsive. I would take it in to have it looked at.
I have never been on a FI that any hesitation let along a bog.




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post #14 of 29 (permalink) Old 08-23-2006, 04:45 PM Thread Starter
 
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Ok two questions on this. Is larry talkin about the dual injection on the 03 cbr's and newer or something else? And I know for a fact that this was not set up for racing, the suspension was all wrong when I got it and the tire was squared off... if anything drag but it hasn't been lowered or streched.

How do you want me to do this from higher gear? No throttle to full... or low throttle to full?

And to Pucky, total rep points cause your totally right. I didn't even think of that cause i'm a tard. And I'll get that EFI synced right propper to whoever advised that.
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post #15 of 29 (permalink) Old 08-23-2006, 09:17 PM
 
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Experience. I let my '83 Chevet Scooter sit for six months when I went to Basic and AIT... My mothers boyfriend didn't put Stabil it it, and I didn't know better until AFTER I MOSQ'd. Thing never did run right until I traded it in for a brand new Cavailer.
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post #16 of 29 (permalink) Old 08-23-2006, 09:53 PM Thread Starter
 
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Uh oh. Translate that into air force talk. MOSQ'd means change of duty station? We call it PCS, permenent change of station... not real permenent tho.
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post #17 of 29 (permalink) Old 08-23-2006, 10:42 PM
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Quote:
Originally Posted by ironmannFB3 View Post
Ok two questions on this. Is larry talkin about the dual injection on the 03 cbr's and newer or something else? And I know for a fact that this was not set up for racing, the suspension was all wrong when I got it and the tire was squared off... if anything drag but it hasn't been lowered or streched.

How do you want me to do this from higher gear? No throttle to full... or low throttle to full?

And to Pucky, total rep points cause your totally right. I didn't even think of that cause i'm a tard. And I'll get that EFI synced right propper to whoever advised that.

I'm not talking about dual injectors. Most of the manufacturers have a second set of butterfly plates that you don't control...they are controlled by the ecu. Yamaha even used a set of diaphrams similar to a cv carb with their early fuel injected sport bikes. Of course, now the fly-by-wire on the new R6 gives them ultimate control.

It's basically the same issue found with mechanical slide carbs. If you open the slide (or butterfly on fi) too quickly, the velocity of the intake air drops suddenly and does not properly fill the cylinder. This causes a hesitation or bog until the intake velocity increases. At that point the engine will take off hard.

On the old superbikes, flatslide carbs were used for their power capabilities. However, if you got on the throttle too quickly exiting a corner, the hesitation and then sudden acceleration often translated into a highside. In fact, the first fuel injected GSXR750's and TL1000's were notorious for having a very sensitive throttle (they didn't have a secondary control system) and they were very difficult to tune for the track. IIRC, even Yoshimura Suzuki ran the older bikes with the carbs instead of the fuel injection at first because they were so hard to control.

BTW, I definitely agree that you should have the throttle bodies synchronized and it would probably be a good idea to make sure the TPS is set properly as well.

Larry

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post #18 of 29 (permalink) Old 08-24-2006, 09:57 AM
 
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Quote:
Originally Posted by ironmannFB3 View Post
Uh oh. Translate that into air force talk. MOSQ'd means change of duty station? We call it PCS, permenent change of station... not real permenent tho.
No, MOSQ is Military Occupational Specialty Qualification... your job training directly after basic training.

The army uses PCS for change of duty station as well, but since I'm National Guard, I don't PCS. I TDY for deployment but home is home.
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post #19 of 29 (permalink) Old 08-24-2006, 02:58 PM Thread Starter
 
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Ok, i was unable to replicate the problem until yesterday. I hadn't concidered the engine hadn't had a chance to warm up properly. So being cautious about pinning a cold engine I went out and just did a couple of quick blips and sure enough the hesitation was there. How about now... Is that normal?

Quote:
Originally Posted by larryg View Post
Well, I'm not a real Honda guy but I can tell you that just about all of the fuel injected bikes use some sort of secondary throttle control. This is used to help keep the intake velocity up when the throttle is opened quickly. Many "racers" like to disable and/or remove these systems in an effort to gain more peak horsepower. The downside is that the engine becomes very sensitive to throttle inputs and requires the rider to be very smooth.
How does disabling this system give more horsepower and why does that make the engine more sensitive? I'm not a big engine guy, but I am a mechanical engineer and I've taken some thermo and fluid dynamics so I might understand some of what you explain.

Last edited by ironmannFB3; 08-24-2006 at 03:03 PM.
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post #20 of 29 (permalink) Old 08-24-2006, 09:31 PM
 
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Quote:
Originally Posted by ironmannFB3 View Post
How does disabling this system give more horsepower and why does that make the engine more sensitive?
The secondary throttle is a butterfly valve. Even wide open, the cross section blocks some airflow. In the old days on carbed cars, the choke was a butterfly valve that would choke or cut off air to make a rich mixture for starting. For racing, where you want max airflow, you could file down the little screw ends that stuck out in the airstream, or completely take out the butterfly valve. I think that's what Larry G meant.
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