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Either by logging the afr/rpm/tps data or
by a competent tuner on a dyno for a fuel
map for your bike/air/altitude/temp/etc.
will provide a very good throttle. Even excellent if done right. I hav never really had poor fueling on any of my 12s. (Turbo was a lot more work) Been my experience that the bikes don’t need the acc pmp

cmg
 

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Acc pump is used when you have large cams, Turbo, etc. and you are using large injectors. However, it's mainly a carb feature and not so much an FI feature. FI can benefit from it, but it's already in the ECM.

I would think it would be great to tune a nitrous set up. You could add an initial, or additional shot of fuel at a certain rpm when it activates.
 

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Any time on lift an engine will go lean. Nature of the beast. Even fuel injection suffers this issue.

The accel pump feature is to combat this. It uses the throttle input to determine if you 'snap' it open and it adds whatever fuel you input for a certain amount of revolutions of the crank on that 'snap'. You determine the amount of sensitivity it uses to determine if you are crackin it open or just cruising. In theory, the sudden rush of air on lift will be offset by added fuel. So this feature is not just for cams or turbo setups. If you understand what it is for, you can set it yourself. It will be a lot more accurate if you monitor your AFR while setting it, but you can play with it. The max amount of revolutions you can set it for is 90 revs of the crank. Very small. It actually does help out with them throttle snaps when you are coming out of a corner, or showing off for friends. Gives ya that lil edge. Takes the slump out of jackin the throttle and takin off like a rocket ship.

Play with it. You'll find where it is fun. I set mine a wee bit rich, cause not like the bike needs it, but the poof of black smoke when I crack it open for the homies sure is funny.
 
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Discussion Starter #7
Any time on lift an engine will go lean. Nature of the beast. Even fuel injection suffers this issue.

The accel pump feature is to combat this. It uses the throttle input to determine if you 'snap' it open and it adds whatever fuel you input for a certain amount of revolutions of the crank on that 'snap'. You determine the amount of sensitivity it uses to determine if you are crackin it open or just cruising. In theory, the sudden rush of air on lift will be offset by added fuel. So this feature is not just for cams or turbo setups. If you understand what it is for, you can set it yourself. It will be a lot more accurate if you monitor your AFR while setting it, but you can play with it. The max amount of revolutions you can set it for is 90 revs of the crank. Very small. It actually does help out with them throttle snaps when you are coming out of a corner, or showing off for friends. Gives ya that lil edge. Takes the slump out of jackin the throttle and takin off like a rocket ship.

Play with it. You'll find where it is fun. I set mine a wee bit rich, cause not like the bike needs it, but the poof of black smoke when I crack it open for the homies sure is funny.
Thanks for the info
I will try and play with it and see what it changes in the sugessted trims of the auto tune
 

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I tried it years ago. Didn't even have huge numbers entered and it fouled plugs.
So I turned it off again and haven't touched it since.
A proper dyno tune will help you the most.
 

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My12R,

Let me make sure I understand what you're saying. Are you saying you think the accelerator pump works when you let off the throttle?
 

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No.

When you open the throttle.
 

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Just to be clear fer ya...

When you open your throttle plates, you incur an initial rush of air that causes you to go lean for a period of time until it balances out. It's not long, depending on the application. This creates a 'dead' spot on that initial hit. Maybe 20 rotations of the crank, give or take (4 or 5 sparks).

Now, the PC3USB has a setting (PCV is a bit more advanced from what I have read, but essentially the same thing) that you can set to negate this dead spot. You can set it to add a couple few percent to the fuel, for an amount of crank revolutions (up to 90 if I remember correctly). This does NOT do this every time you are on the throttle, nor is it a global change. There is a setting for your throttle to trigger this to happen. It has a sensitivity setting. So say, you set this a bit higher, you have to twist the throttle open relatively fast and farther to trigger it (like coming out of a corner hard or just straight line hit). It will trigger, add your specified amount for your specified revvs, and that's it. It will ONLY TRIGGER when you jerk that throttle open that far and fast each and every time. Not every time. If you set this sensitivity low, it will trigger every time you leave a stop light under light throttle. You don't really want or need this, so turn that up a bit.

As far as fouling plugs....not sure how you're doing this with the feeble amounts of fuel added for such short durations. Maximum amount of squirts is 45 with a very slight increase in duty cycle. At 4,000 RPM, at max settings, triggering this on a downshift is a little more than 1 second. If you're at 8,000 RPM, less than a second of added fuel. At 4,000 RPM, your crank turns 66.666 times a second. You don't need max revvs (90) to negate this lean hit.

Carbs had this built in for the same purpose. Even motorcycle carbs have them in some applications to this day. They are fixed in carb applications, so what they are is what they are. Fuel Injection offers a far superior tuning ability for this. On newer bikes, you have the ability to monitor AFR with add on items. Older, you either know someone or pay someone or guess for fun. Either way, it shouldn't hurt anything using this. Like I said, I set mine up to puff black when I crack it. Never fouled a plug nor had an issue.

Juss a lil info fer ya's....
 

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Discussion Starter #12
Dyno jet says for the pcv 89 will give you 1 second of extra fuel if you crank it open at 5000 revs and about 2 seconds of extra fuel at 2500 revs. I've played about with it and have noticed pull alot better I set it to trigger at 45% increase in throttle position for 75 cycles and an increase of 25% fuel feels great. What I will add though this is also achieved by the auto tune if you do your test runs with opening the throttle hard it will add alot of fuel but if you do your test runs easy it's adds alot less fuel giving evidence to what you said about initially running lean for a moment when opening the throttle hard. I'm taking the advice of jpowel490 and getting a map switch for the pcv. I'll autotune a rich map and do some runs when I open the throttle hard to counter act the lag and I'll autotune a normal map for riding back and forth from work. For the rich map I'll set the acc pump for the rich map to trigger higher maybe about 60 % and for the normal map to trigger at 40% think this will be the best balance for me... Just need to buy that map switch now 😁
Thanks for all the info guys it's all very much appreciated
 

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I didn't read that book you wrote, but carbs did it to have an idle circuit. Many race carbs didn't have one because it was wide open most of the time and didn't need to idle. Now if you needed an idle, you bought a carb with accel pumps.

With EFI on these bikes, stock bolt ons, I see absolutely no reason to implement that setting.

AFR by gear, accel pump enabling, etc. is just a way to screw everything up. It will never run right and you will foul plugs like crazy. Nothing worse than dumping fuel at idle and part throttle to an EFI bike that has that already programmed in.
 

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Discussion Starter #14
I didn't read that book you wrote, but carbs did it to have an idle circuit. Many race carbs didn't have one because it was wide open most of the time and didn't need to idle. Now if you needed an idle, you bought a carb with accel pumps.

With EFI on these bikes, stock bolt ons, I see absolutely no reason to implement that setting.

AFR by gear, accel pump enabling, etc. is just a way to screw everything up. It will never run right and you will foul plugs like crazy. Nothing worse than dumping fuel at idle and part throttle to an EFI bike that has that already programmed in.
So far I haven't had any problems, bike is running way better than stock, if it keeps running how I want it and the plugs don't get fouled up I'll keep the afr by gear and the acc pump enabled, almost no fuel gets added at idle just enough so it runs sounds smooth.
 

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...

Uhm.........ok sir. Tis why the rod that pumps the diaphram is connected to the throttle linkage then I spose. Must be why when you open the throttle, that little rod moves and squishes more fuel into the venturies...

Same with the fuel sticks....wonder why it says throttle opening and duration if it is for idle purposes. Hell, the name "accelerator pump" should be changed to "idle pump". Prolly should get rid of them pesky 'pilot jets' too. After all, if we have a pump for that that is actuated by opening the throttle for idle, we don't need jets for that job.

This kind of shit right here is why I don't post very often anymore. You realize this shit is what I do for a living, right?

.....kids.

Edit:

For your casual reading sir....

 

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Oh yea.....on a side note....

You should probably read my "books" and "dribble". It would seem you would benefit from it, considering you're both erroneous in you assumptions about some features and functions of engine performance items, such as the mysterious "accelerator pump" that apparently does the idle circuits and fouls plugs.........

But in reality, I know you did read it. If ya din't, you wouldn't reference it in your response.😉
 

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Doesn't take a genius to figure it out...
I'd never fouled a plug before. Bike had been dyno tuned and ran great. Decided I'd have a look at the features on the PC.
Turned feature on, started fouling plugs.
Turned feature off and the fouling stopped and haven't had a plug foul since.
Yes I did adjust the settings numerous times to see if it would get better or actually do anything useful for me.
Dont need to read a book to tell me what was happening, just used my practical common sense.




Play with it. You'll find where it is fun. I set mine a wee bit rich, cause not like the bike needs it, but the poof of black smoke when I crack it open for the homies sure is funny.
/enough said.....
 
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