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Discussion Starter #1
There are many threads here and loads of pages all across the net about what these things do, filled with lots of speculation and heresay.
I'd like to get the truth, if anyone actually knows it.

Here are some of the rumors:

I'll start with the Rev Limiter, since that one's simple.
Just about all modern bikes have a limiter. It stops the engine from spinning too fast. Otherwise, the valves can float and smack into the piston (bad). Rev limiter is generally set just below the point where the engine would explode, usually a few RPM above redline. There's really no point in trying to rev higher than this, since you'd be well past peak HP.
Rev limiters usually work by cutting (completely eliminating) the spark. Sometimes, they fall at almost perfect shift points, and since they work the same as a quickshifter, preloading the shift lever and running the bike full throttle into the rev limiter can mean very fast and precise shifts. I haven't tried it, but I'd guess our bike does NOT fall into this category. (Oh, sometimes I really miss my Ducati...)
Redline is generally set where sustained riding would be bad for the engine, where oil circulation is reduced, or crank of tranny input bearings would overheat. Very short term use is fine, though, and optimum shift points often fall just past redline. (Again, probably not the V-strom).

On the V-strom, IIRC, rev limiter is set at something like 11,000rpm, and is the same in every gear.
On some bikes, the rev limiter does limit top speed, but if you're hitting 11,000 rpm in 6th on a V-strom, I'd like to know what kind of turbocharger you're running.
It has also been claimed, however, that in 6th gear, the DL1000 does have an earlier rev limit, specifically to limit the top speed.


Okay, next up: The Secondary Throttle Butterfly Valves, or "secondaries".
These things restrict the airflow going into the engine.
Off-topic, but this has always bothered me. Throttle is a verb, meaning to "choke" or restrict airflow. Therefore, "full throttle" should mean to fully restrict the air, just like to apply choke means to reduce air and richen the mixture. But for some reason, "full throttle" means "wide open butterflies" in our culture....okay, rant over.
General consensus on the net is that these things make the bike smoother. They are controlled not by the throttle cable or your wrist, but by a servo motor that opens them and closes them when the bike's brain sees fit. If it opens them slowly, you get as less responsive, smoother ride. So, people take them out because they like the big jerks and wheelies when they whack open the throttle.
Some people say it makes the bike more powerful. Some say it doesn't make the bike more powerful, just more jerky, which might feel like more power. There are rumors that the Bike Brain closes them again if it thinks you're going too fast, reducing horsepower (and therefore speed) in the upper gears. I don't have any idea if this is true or not, but I would like to know. Seems like a Dyno would easily show this, but I've never seen any back to back graphs with no other variables changed.

Lastly, there's the ignition retarding, which seems to have even more conflicting info floating about on the series of tubes.
Some bikes retard the ignition at low rpms, in order to run lower octane fuel that would otherwise ping (with faster revs, the gas doesn't have time to ping before the pressure is reduced and it goes into the exhast stroke).
Some bikes use retarding to limit top speed (ZX-14, Hayabusa) and others use in "something similar to traction control that doesn't work as well" (Kawasaki KIMS), or even to smooth out jerky drivetrain lash (Honda CBR1000RR). Any any case, a delayed ignition means less power/torque from the given amount of fuel.

On the DL1000, it seems more complicated.
It seems that timing is retarded in gears 1, 2, 3, and 4, or gears 1, 2, 5 and 6, depending on what you're reading. It seems the timing is later from 0 to 50% throttle, and the earlier ignition begins after that. In low gears, that means you get full power when you want it, and lower power at more reasonable speeds. Some claim that this is for better traction on dirt, some claim it's just for smoother street riding, in which case it seems rather redundant to have both this and the secondary butterflies to smooth out power.

The ignition retardation in the upper gears is even more obfuscating. One reputable source claims that as the DL1000 does NOT have a different rev limiter for upper gears, the ignition map is used to limit the bike's top speed. This same source claims that the timing retard is only in effect in the lower 50% of throttle position. What this means is that there is a top speed limiter on the bike, but it's only in effect if you're not going very fast. Once you give the bike enough throttle to approach its top speed, the bike has no speed limiter.
In the upper gears, then, the retard serves only to lower the effeciency and performance of the bike at steady cruising speeds. Put another way, shifting up into overdrive will engange the electronics to lower your fuel mileage. Presumable not as much as if you stayed in Fourth gear, but still some.

Clealy, there's a lot of confusing and inaccurate information out there, easily enough to overwhelm someone who tries to search for a quick answer.

The following is a list of questions for which either no or multiple answers can be found online. I hope someone will be able to answer them, and that this information will prove useful to others in the future.

1. What is the rev limit on the DL1000?
2. Is the rev limit the same in every gear?
3. Do the Secondary Butterfly valves have the same effect in every gear?
4. Do the Secondaries limit horsepower in high gears?
5. Are the secondaries responsible for limiting the top speed of the DL1000?
6. Do the secondaries have any effect on peak Horsepower?
7. Do the secondaries provide a delay between a full twist on the throttle, and full horsepower at a constant RPM?
8. Do the secondaries make wheelies more difficult?
9. In which gears is the Ignition Timing retarded?
10. By how many degrees is Ignition retarded?
11. Do people who use timing retard eliminator products ever have issues running low octane gasoline at low RPMs?
12. Is the ignition fully advanced whenever the throttle is above 50%?
13. In low gears, is the purpose of the retard to smooth throttle response, drivetrain lash, traction in dirt or undesirable surfaces, or something else?
14. In low gears, how does the role of the retard differ from the role of the secondaries?
15. Which has a bigger effect: removing the retardation, or the secondaries?
16. How do the results of #15 differ?
17. Why is there no timing retard in 4th gear?
18. In upper gears, why is the ignition controlled "speed limiter" disabled when giving over 50% throttle?
19. In upper gears, why is ignition retarded for the commonly used range (below 50%)
20. What improvement in fuel economy can be realized by eliminating the retardation in the higher gears?

Okay, my fingers are tired and I know I've asked a lot of questions. Sorry this is so long, but I hope you can understand my frustrations with all the misinformation strewn across the net.
-Skippii
 

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My guess would be that there are few people in the world who actually know the definitive answers to all these questions. Suzuki may not even be willing to provide detailed answers to all this.

Or you could just ask SittingDuck. He knows the wrong answer to everything.
 

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Ya' forgot to ask about the sound of one hand clapping...

:rolleyes:
 

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My guess would be that there are few people in the world who actually know the definitive answers to all these questions. Suzuki may not even be willing to provide detailed answers to all this.

Or you could just ask SittingDuck. He knows the wrong answer to everything.
You need to put a warning out the next time you make a joke that funny. I had coffee come out of my nose from the laughing. :D:cool:
 

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Is it really that important? What are you really trying to figure out.

Why would anyone take the time to try and answer any of that?
 

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Skippii

The answer to all of those questions is available if you want to spend the time to look them up. :bom_idea::bom_idea::new_confused2::new_confused2:
 

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Discussion Starter #10
I hope you don't lay awake nights thinking about this.
You know, I don't have any idea why this stuff bothers me so much. The whole idea of pointless engineering, all these extra doohickeys that don't seem to do anything (or worse, reduce performance without reason) just really bothers me. I mean, why spend all the effort on making three different top speed limiters, when they could be doing something like aligning the rear sprocket correctly?

Is it really that important? What are you really trying to figure out.
I'm just really curious. When I have an interest in something, I spend a lot of time and effort learning as much as possible about it. Maybe it's just me?

awd505 said:
Why would anyone take the time to try and answer any of that?
...I guess it is just me, then.

Think less, ride more....
Secondaries are debated regularly...simply try it and see if you like it.
I've read enough about them to think that for my purposes, they are probably beneficial to me. I ride a lot of dirt, and smoothness is a plus for me. My concerns with them are really about educating myself and learning as much as possible about how and why they work.

I can help you answer a few of your questions:
1 and 2: I think it would be, yes, it's easy enough to try out (on my wee at least, the rev limiter seems to kick in at the same rpm for 1-2-3, i haven't bounced off it in 4-5-6, and don't know if the wee goes fast enough for that. maybe on a dyno with no wind resistance)
I just had a thought. I'll be changing my tires soon. While I'm at it, I'll probably pull the chain off the countershaft sprocket, and maybe give it a full throttle run with no chain on in different gears, to see where it cuts out.
Any reason this would be a really bad idea?

3, 4 and 5: the secondaries always have the same effect, the have the effect that the ecm tells them to have. their purpose is to buffer wrong throttle application and compensate for differencess in athmospheric pressure, like the vacuum slides in a cv carb). of course, the ecm can use them for other stuff, like maybe restricting airflow to limit horsepower. that's how we'd limit the power of racecars to make sure we had an even playing field for different displacement engines (restrictor plates on the throttle bodies).
I don't know if it's gear related on the strom, it could be, but i think the ecm only knows or cares if you're in neutral or 6th (gw can probably confirm this).
I suppose I could test this as well, but I'd probably prefer not to run the engine with no air filer in place.
My concern about yoru answer here, is that you said the engine only knows if you're in N or 6. Ivan's Performance says their TRE works by fooling the engine into thinking it's in 4th gear at all times. That would indicate to me that ignition maps MUST be different for all (or most) gears, and therefore the ECM would have to know the difference between all the gears.
6: probably not, since they're theoretically fully open at that point
Makes sense.
7: no, if you're at a constant rpm, twisting to full throttle will not increase your horsepower. horsepower only increases as your rpms climb. whacking the throttle to full open at the wrong rpm can bog the engine down (if you've ever ridden a carburated bike with mechanical flatslides and accelerator pumps, you knwo what i'm talking about). the secondary butterflies prevent this by opening gradually, in order to not feed the engine more mix than it can handle under a certain load at a given rpm. when whacking the throttle open at the right rpm, there probably is a very small delay before the secondaries react.
I don't mean any disrespect, but you're very wrong about this. Putting more fuel and air in the engine WILL increase torque, which automatically increases power.
8: not if you use the clutch to wheelie;) imo, wheelies should not be done by clutch-dump or throttle whack, but by clutch-slip and/or throttle roll-on. this way your drivetrain doesn't take such a big whack which is bad for chains and sprockets, but especially for engine and transmission bearings.
I should have clarified: was talking about power wheelies, by whacking open the throttle. My logic tells me that the secondaries would make the bike less responsive to this sort of thing, as you have to wait for them to open. Anyone know how long it takes for the servomotor to fully open the secondaries?

Skippii
The answer to all of those questions is available if you want to spend the time to look them up. :bom_idea::bom_idea::new_confused2::new_confused2:
And not just "the" answer, but Many, MANY answers, usually completely contradictory. I spent several hours researching all of this before posting the question. This question was my reaction to not being able to discern which, if any, of the multiple answers I found were actually correct.
 

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Discussion Starter #11
re. the second quoted paragraph:
what I meant is the rpms wouldn't stay constant. putting more fuel and air in the engine will increase the rpms, with a proportional torque and power increase.

But they COULD stay constant, and if they did, there still would be more power.

You can ride at 4,000 rpm in 6th at 10-15% throttle, maintaining about 70mph.
Your bike is putting out relatively little power.

You can also ride at 4,000 rpm in 6th at 100% throttle, maintaining 70 mph, and applying some brakes at the same time. Now, your bike is producting MUCH more horsepower. Same RPM, more throttle=more horsepower. Enough extra power to boil your brake fluids and maybe even turn the rotors red.
 
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Wow, Skippii and the Duck, what a pair.;) While you're at it, when you've got it up around redline shoot in a little ether, see if you can get past the rev limit that way...When I was racing jackrabbits we'd do that to get 'em going good and fast.
 

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Wow, Skippii and the Duck, what a pair.;) While you're at it, when you've got it up around redline shoot in a little ether, see if you can get past the rev limit that way...When I was racing jackrabbits we'd do that to get 'em going good and fast.
How did you get the jackrabbits to sniff the ether?

I'd like to see that!
 

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I just had a thought. I'll be changing my tires soon. While I'm at it, I'll probably pull the chain off the countershaft sprocket, and maybe give it a full throttle run with no chain on in different gears, to see where it cuts out.
Any reason this would be a really bad idea?
I think it's an awesome idea. Do it twice and come back with your report.
 

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Wow, Skippii and the Duck, what a pair.;) While you're at it, when you've got it up around redline shoot in a little ether, see if you can get past the rev limit that way...When I was racing jackrabbits we'd do that to get 'em going good and fast.
No wonder your rabbits were so slow you were putting them to sleep, I used a dried out corn cobb and Heat liniment on the back end of my rabbits to get them moving. Worked great for sprint racing.
 
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No wonder your rabbits were so slow you were putting them to sleep, I used a dried out corn cobb and Heat liniment on the back end of my rabbits to get them moving. Worked great for sprint racing.
I wondered why theyt were so drowsy. I think it'll work really well for the chainless redline run though. ;)
 

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You need to put a warning out the next time you make a joke that funny. I had coffee come out of my nose from the laughing. :D:cool:

Yup, I agree...now to clean the coffee off of my new 22" monitor at work!!

jeff
 
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