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
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
