My sprocket experiences on a GS500.

[MeeLee]

By changing the stock gearing from 16/39t to 17/35t you can drop quite some rpms on the highway.
Doing so, i had to get a 108 link chain, as even the stock 110 link would bring the adjustment all the way to the end, with no room left for adjustments.

Initially I had bought a 106 link chain, but it barely fit the 35t rear, and I couldn't get the 17t front on it. The bike rode quite fine, though gears where still a bit short.
When I say short, I mean that the bike'sgears are tuned for gear shifting at 4-8k rpm range. A drop of 1000rpm shifting in that range, only means a drop of half that RPM when shifting in the 2-4k rpm range.
Most of the time, I try to ride moderately,  between 3-6k rpm shifting, and thus I need longer spacing between the gears.

That, and the fact that most of my riding is between 35 and 50mph, and I want to do that in final gear, with an as low rpm as possible.

So for that purpose, combined with a good sprocket and chainlink ratio, I calculated that I would need. 17/35t setup.
The 17/35t work excellent on a 108link chain.

However, a 17/35t does have 2 inherent problems:
1- being that idling in 1st gear gets the bike going at almost 6mph. Not fun in traffic, and sometimes feathering the clutch is needed in start-stop traffic and uphill.

And 2- that it's hard to get the bike past 80mph in final gear.
Ducking forward, over a good minute or so the bike does finally get to 105mph indicated. It just shows me that the bike has enough power, but barely.

For that, a 17/36t would give me the power to get to 105mph indicated a lot faster, since the bike will have higher HP with the 300rpm higher revs at those speeds, and have a tad higher torque to the rear wheel as well.

So from a performance point of view, a 17/36t makes most sense.
The only problem I'm facing, is that with a 108 link chain, the rear sprocket will wear out the chain (or reverse). Sprocket/chain ratio couldn't be worse.
With the stock 110 link chain, the rear wheel chain adjustment will be close to the end, but it'll still be ok! Also chain-link/sprocket wear is quite good!

Another inheritent problem I've noticed, is that changing the gear ratio, somehow affects the air/fuel mixture.
The bike has no problems going WOT in 4th or even 5th gear, but 6th gear with the 17/35t, the engine load is different, and I have the impression that I need to get a bigger main jet. It is funny to note, that these problems are almost non-existent with the stock gears, or running 80+ mph at 7+k rpm.
They do appear when doing the same thing at 5k rpm.

A 17/36t has less of a problem than a 17/35t with the af ratio (and the throttle losing power the last 10-20%).
It gives the hair more power the engine needs to get to top speed of 105mph indicated, without over revving the engine, and still allowing to reach 112+ mph top speed indicated, in 5th gear at 8700rpm.
It also has less problems with low rev engine vibrations. A 17/35t can't get rpm lower than 2750rpm or the engine will give odd vibrations. A 17/36t might bring that down to 2600rpm.

[Atesz792]

Anyone (esp. new riders) reading this later: MeeLee here does what many like to call "hypermiling".
You don't want to start experimenting with a GS you have just bought.
You don't want to lug a high-revving (for a twin at least) GS engine.
The stock gearing is just perfect for ~95% of GS riders, 6th already being an overdrive gear.
I'd advise anyone not to start messing with the stock gearing until they have ridden the bike at least 10k kilometres (~6k miles).

For someone interested in hypermiling, this is good information.
YMMV, peace

[Suzuki Stevo]

I went 17/39 and could get 65 Mpg any day of the week on the open road, once I got 69.8 Mpg not even trying. What are you trying to do here?

[Janx101]

A jetting problem that only exists in 6th? .. isn't that called wind resistance?

[twocool]

You are right on with your reply to Mr. Lee....

Mr. Lee is insane....

Lugging and engine is just about the worst thing you could possibly do.

The only gear ratio that would have anything to do with mileage is 6th....as you said, 6th is already a very high gear for the GS (like an overdrive)...but going to a high gear and low RPM will not necessarily give better mileage......if you are over geared, you need wide throttle to accelerate...this will cause bad mileage...

the way to get good mileage on the GS 500 is to use the throttle wisely...smooth accelerations without full wide open throttle...keep the speed down to 50 or 55 mph.....

Faster speeds, jack rabbit starts, full throttle operation ..all will give poor mileage...

Driving carefully will give gas mileage in the low to mid 60's

Driving like a nut will give mileage in the low 50's or less...

But in the scheme of things...5 or 10 MPG is meaningless....

Cookie

Anyone (esp. new riders) reading this later: MeeLee here does what many like to call "hypermiling".
You don't want to start experimenting with a GS you have just bought.
You don't want to lug a high-revving (for a twin at least) GS engine.
The stock gearing is just perfect for ~95% of GS riders, 6th already being an overdrive gear.
I'd advise anyone not to start messing with the stock gearing until they have ridden the bike at least 10k kilometres (~6k miles).

For someone interested in hypermiling, this is good information.
YMMV, peace

[Dr.McNinja]

Another inheritent problem I've noticed, is that changing the gear ratio, somehow affects the air/fuel mixture.
The bike has no problems going WOT in 4th or even 5th gear, but 6th gear with the 17/35t, the engine load is different, and I have the impression that I need to get a bigger main jet. It is funny to note, that these problems are almost non-existent with the stock gears, or running 80+ mph at 7+k rpm.
They do appear when doing the same thing at 5k rpm.

Maybe I don't know enough about engines, but how is it possible the gearing of the bike affects the AFR? The AFR should be dependent only on the carbs, once the carbs give the engine the juice it needs the power from the combustion is send to the drive shaft and that's where the gear takes place.

Have you considered you over-geared down your bike and it's lugging as a result of extra strain placed on the clutch/gears/sprockets? I'd check this because AFR based on gears makes no sense and if this is the case you could be causing premature wear and warping to your bottom end.

Next question is, why try to get more mpg out of the bike anyway? The gs engine already leaves so much to be desired and is so underpowered - you can get some fun out of it dropping a few teeth on the sprocket, rejetting, cutting out the cat coverter + PAIR system, etc and still get 40+ mpg.

[Dr.McNinja]

Stupid computer doubleposted. Mods delete this one thanks.

[Alan_nc]

Nice to have some "comic relief" on the site.

Hope the newbees realize that is what MEELEE provides.

[MeeLee]

1- There's no such thing as lugging this engine above 3k RPM with these gearing. At the very worst perhaps when you're going past 85MPH; perhaps... We've had this conversation many times before. Lugging an engine like this at speeds between 35-80MPH is a Childs tale to scare the good people of thinking about efficiency.
I'm not going to argue this, I've had enough arguments about engine lugging, and enough miles on my past engines to prove it's a non issue. Sure you could lug your engine, but then you'll know when you do so. The engine will let you know (vibration).

Also, this is not considered hypermiling. Hypermiling includes using the clutch to 'roll' to a stop, with or without turning off the engine while doing so. I think 'eco-modding' will be a more correct term.

2- AFR is affected because the engine is under heavier load. That means valves stay open longer than under lighter load higher RPM, while at the same time. More air gets sucked in than fuel when the valves stay open longer (due to lower RPM), and the airfilter restricts less airflow at 5k rpm than it does at 8 or 9k rpm.
It does seem to affect the AF ratio.


And twocool, just because you don't agree with my way of riding, is no reason to call me 'insane'.
It's just not proper etiquette.
A lot of people are doing this to their bikes all over the world. There are still people out there who prefer 'just enough' power and good MPG, over 'plenty of acceleration, and high rpm'.
At the very least I would request the same politeness as anyone else gets in this forum; even if your views differ from mine!


And lastly,
People love to comment how 'impossible' and 'stupid' these mods are, but I find that many times people like me have tried it before, quite often a couple of years to a decade before, and where considered very knowledgeable, and their words where honored. Whatever I bring up here is not new knowledge! It's been proven and tried by many who now have several tens to 100's of K miles on their bikes.
I'm sure even in this forum there are a bunch of people who tried it before and are very content with it!


I never told anyone to do my mods, I just shared my findings in this thread (and opinions about 15/36t probably being better than 15/35t). That's all... No reason to get on the attack horse because your riding style differs from mine.

[Dr.McNinja]

2- AFR is affected because the engine is under heavier load. That means valves stay open longer than under lighter load higher RPM, while at the same time. More air gets sucked in than fuel when the valves stay open longer (due to lower RPM), and the airfilter restricts less airflow at 5k rpm than it does at 8 or 9k rpm.
It does seem to affect the AF ratio.

And lastly,
People love to comment how 'impossible' and 'stupid' these mods are, but I find that many times people like me have tried it before, quite often a couple of years to a decade before, and where considered very knowledgeable, and their words where honored. Whatever I bring up here is not new knowledge! It's been proven and tried by many who now have several tens to 100's of K miles on their bikes.
I'm sure even in this forum there are a bunch of people who tried it before and are very content with it!


I never told anyone to do my mods, I just shared my findings in this thread (and opinions about 15/36t probably being better than 15/35t). That's all... No reason to get on the attack horse because your riding style differs from mine.

I was under the impression AFR is independent of RPM and is determined by throttle position because the throttle controls the position of the butterfly valve which varies the vacuum and thus, the fuel and air being pulled in. Since you geared down your engine, the engine won't be able to draw in as much air and fuel (both I would guess, not just one) and you'd be getting chugging around 3/4 to WOT like you said. I don't think you have a sweet spot at any RPM because the AFR should be determined by weather or not you're WOT. It probably gets better as the engine picks up only because the engine is finally able to overcome the gear down. It's like when you swap a geared down V8 big block into a rock crawler. You'll destroy your engine trying to push it past 70.

If this is the case then a bigger main jet like you suggested would likely stop it from leaning out so much at 3/4 to WOT. I'd be concerned that if the engine is struggling at WOT you could warp your piston rods or something.

Addressing the last part, we're just questioning the futility of this effort. Why not buy one of those $500 chinese scooters that can go 60mph and get 100mpg if you want insane fuel economy?

[MeeLee]

2- AFR is affected because the engine is under heavier load. That means valves stay open longer than under lighter load higher RPM, while at the same time. More air gets sucked in than fuel when the valves stay open longer (due to lower RPM), and the airfilter restricts less airflow at 5k rpm than it does at 8 or 9k rpm.
It does seem to affect the AF ratio.

And lastly,
People love to comment how 'impossible' and 'stupid' these mods are, but I find that many times people like me have tried it before, quite often a couple of years to a decade before, and where considered very knowledgeable, and their words where honored. Whatever I bring up here is not new knowledge! It's been proven and tried by many who now have several tens to 100's of K miles on their bikes.
I'm sure even in this forum there are a bunch of people who tried it before and are very content with it!


I never told anyone to do my mods, I just shared my findings in this thread (and opinions about 15/36t probably being better than 15/35t). That's all... No reason to get on the attack horse because your riding style differs from mine.

I was under the impression AFR is independent of RPM and is determined by throttle position because the throttle controls the position of the butterfly valve which varies the vacuum and thus, the fuel and air being pulled in. Since you geared down your engine, the engine won't be able to draw in as much air and fuel (both I would guess, not just one) and you'd be getting chugging around 3/4 to WOT like you said. I don't think you have a sweet spot at any RPM because the AFR should be determined by weather or not you're WOT. It probably gets better as the engine picks up only because the engine is finally able to overcome the gear down. It's like when you swap a geared down V8 big block into a rock crawler. You'll destroy your engine trying to push it past 70.

If this is the case then a bigger main jet like you suggested would likely stop it from leaning out so much at 3/4 to WOT. I'd be concerned that if the engine is struggling at WOT you could warp your piston rods or something.

Addressing the last part, we're just questioning the futility of this effort. Why not buy one of those $500 chinese scooters that can go 60mph and get 100mpg if you want insane fuel economy?

About the Chinese scooters/motorcycles: Been there, done that.
About warping anything in the engine: At low RPM there's less force on the bearings or anything else than at high RPM. See HP curve, engine at 2k lower RPM makes also lower HP.

About A/F ratio, like I said, the stock airfilter limits high air volume. Like it's not good enough to let all the air pass near to resistance free at high RPM.
That's why a lot of people equip it with K&N airfilters, or the lunchbox airfilter.
In essence, the bike at 90MPH sucks in less air at 5k RPM than at 8000 RPM. The higher air suction gets more restricted at 8K RPM with the stock filter (not so with a free-flow air filter); thus the bike gets a richer mixture at high RPM with the stock filter than with a free flow filter; or than when riding WOT at 2/3rd the RPM.

Since there's less vacuum resistance at the filter at lower RPM doing exactly the same performance as a stock gearing does at higher RPM, the bike will be running leaner (less fuel, more air).

So, yes, it does affect AFR.

[Big Rich]

Meelee, I'm really trying to understand your line of thinking on all this. Really. I'm not into reposting huge quotes on my phone, so I'll just copy and paste snipped sections. First off, what is the reasoning for increased chain sprocket wear mentioned here:

"The only problem I'm facing, is that with a 108 link chain, the rear sprocket will wear out the chain (or reverse). Sprocket/chain ratio couldn't be worse.
With the stock 110 link chain, the rear wheel chain adjustment will be close to the end, but it'll still be ok! Also chain-link/sprocket wear is quite good!"

Another thing that caught my eye is the AFR discussion. If you're essentially lugging your engine in 6th gear, a main jet change will help VERY little with that. And I'm failing to see the true relationship between gearing changes and AFR - Wot is wot regardless of how many teeth are on your rear sprocket.

[MeeLee]

The chain and sprocket wear depend on how many rotations the sprocket needs before the same tooth goes into exactly the same link. Optimally, with an even linked chain, you'd have an odd number of tooth. Let's say it was possible to have x-amount of links, on a 39T rear sprocket, the sprocket will need 39 rotations before the tooth hits the same chain link again (at best).

At worst (for ease of calculation), each tooth of the sprocket will hit the same link every rotation.

If you go to the bottom of gearing commander, you'll see it all calculated right there.

Define lugging the engine.
What does the engine do under load?
Just because the final gear is an overdrive, doesn't mean the engine will suffer shorter life.
Take a look at Citroën's 2cv. It had such an overdrive that the engine barely accelerated the car in 4th gear, and got 80MPG (for a car). Yet some of these cars got over 250.000km on them without an engine rebuild.

The difference of AFR lies in the amount of air intake that the engine gets.
The stock intake is restrictive. It creates more of a vacuum at high RPM than at low RPM.
That's the relation. It's like equipping a free flow air filter on the carburetor, you'll get similar amount of vacuum between air filter and carburetor with a free flow air filter at 8k RPM (as close to none) as using a restrictive air filter at lower RPM (close to none, but increased at high rpm).
That's where the correlation lies.

What a lot of people may be experiencing is perhaps the AF ratio being off, when going into tall gears, rather than lugging.

An engine that is taxed too high, will start knocking (piston motion is too much slowed down, that the spark fires at a too early stage; and is very similar to advancing your timing).
So instead of advancing your timing, you're slowing down the engine by increasing the load, and have the spark detonate at a better position; using taller gears it results in better efficiency and higher MPG.

A lot of people advance the timing. The shorter the gears (the smaller the counter sprocket, and larger the rear sprocket), the more the timing advance can be, and similar the taller the gearing, the more tardy the mechanical motion becomes and has a similar effect as advancing the timing.

There's no way you can destroy an engine due to too tall gears, unless you plan on going top speed with it, or going below an RPM that the engine is comfortable with pulling (2.75k rpm in my case, lower in lower gears).
There are limits of course, but my gear change is less than 20%, and is well within the acceptable range of modding most bikes.

[J_Walker]

if you wanted something to ride better at highway speeds, and got good MPG.. there's plenty of 800cc-1000cc bikes that are meant for that! 

[Big Rich]

Hmmm.... not quite the answers I was hoping to get.

First, I do understand the sprocket / chain wear issue.

Second, I'm not understanding the logic of gearing changes and AFR. Regardless of what modifications have been done to the air intake (to an extent) / exhaust / sprockets / tire sizes / etc, CV carbs rely on the throttle position and vacuum from the engine to operate. So I'll repeat: wot is wot regardless of sprocket size. Now, if the gearing is so tall that the engine can't overcome wind resistance, you can hold the throttle wide open but never reach full vacuum.

Forget about what filter resists more flow at whatever rpm. If you aren't holding the throttle at wide open and the rpm's aren't close to matching, you aren't fully on the main jet. To put it another way - I'd like to see the dyno test results of running with stock gearing and your gearing for a comparison. If there is no change in horsepower and torque curves, than the air / fuel mixture is not affected.

[PantheraLeo]

MeeLee, there is no "free flow filter", I believe you mean lower pressure drop filter.

Any filter, by definition has a pressure drop.  A zero pressure drop filter is doing zero filtration.  If the filter area is increased, the pressure drop associated with the filtration can be markedly reduced, but never eliminated.  There is always a pressure drop across any filter that has air moving across it.  You are correct that decreasing this pressure drop is frequently favorable to efficiency...but...if you are running lean, it is likely due to the fact that the carbs are designed for X pressure drop, and you have reduced the pressure drop so that the new number is X-Y pressure drop.  I think you have not modified your carbs, correct?  Therefore, it stands to reason that your lean issue has nothing to do with sprockets and more to do with your filter modifications which have increased air flow while leaving fuel levels unchanged.

In my business I also do a great deal of engineering with pulleys (in relation to fan speeds and outputs), sprockets are using that same basic science that governs pulleys.

I am not an expert on motorcycles (yet!), but I know a great deal about pressures, flows, and the relationships between the various factors that determine flow.  I don't know enough about how the air intake is affected by throttle to say for sure, but it seems to me that higher RPM would induce more air than lower RPM....therefore, running a "long" sprocket combination to reduce rpm would make the air flow less (if anything), thus making the mix in the carb richer...

I do follow what you are saying with the sprocket changes you have made, and even if I don't fully understand why you are doing it, it is interesting.

[MeeLee]

MeeLee, there is no "free flow filter", I believe you mean lower pressure drop filter.

Any filter, by definition has a pressure drop.  A zero pressure drop filter is doing zero filtration.  If the filter area is increased, the pressure drop associated with the filtration can be markedly reduced, but never eliminated.  There is always a pressure drop across any filter that has air moving across it.  You are correct that decreasing this pressure drop is frequently favorable to efficiency...but...if you are running lean, it is likely due to the fact that the carbs are designed for X pressure drop, and you have reduced the pressure drop so that the new number is X-Y pressure drop.  I think you have not modified your carbs, correct?  Therefore, it stands to reason that your lean issue has nothing to do with sprockets and more to do with your filter modifications which have increased air flow while leaving fuel levels unchanged.

In my business I also do a great deal of engineering with pulleys (in relation to fan speeds and outputs), sprockets are using that same basic science that governs pulleys.

I am not an expert on motorcycles (yet!), but I know a great deal about pressures, flows, and the relationships between the various factors that determine flow.  I don't know enough about how the air intake is affected by throttle to say for sure, but it seems to me that higher RPM would induce more air than lower RPM....therefore, running a "long" sprocket combination to reduce rpm would make the air flow less (if anything), thus making the mix in the carb richer...

I do follow what you are saying with the sprocket changes you have made, and even if I don't fully understand why you are doing it, it is interesting.

You pretty much understood what I tried to explain, and where more able to explain it than me, seeing your technical vocabulary in English is larger than mine.

There is one error in reasoning though;
At higher RPM, there is more airflow, thus also more air resistance with the stock filter.
More air resistance means more vacuum, thus more fuel from the jets goes in the mixture, and less air.
In other words, the mixture will run richer. With less airflow, there is less vacuum, thus less fuel in the piston, and more air, as it flows freer than fuel.
Lower RPM means running leaner for the same speed, as doing the same with high rpm.

You're right in the assumption that I haven't yet changed the main jet; it should still be pretty much stock, and it needs to be at least 5 sizes higher.

But thanks for the explanation; you're doing a better job than me in that field for sure 

[twocool]

Holy cow!

in plain English:   "It just don't work that way!"


Cookie

MeeLee, there is no "free flow filter", I believe you mean lower pressure drop filter.

Any filter, by definition has a pressure drop.  A zero pressure drop filter is doing zero filtration.  If the filter area is increased, the pressure drop associated with the filtration can be markedly reduced, but never eliminated.  There is always a pressure drop across any filter that has air moving across it.  You are correct that decreasing this pressure drop is frequently favorable to efficiency...but...if you are running lean, it is likely due to the fact that the carbs are designed for X pressure drop, and you have reduced the pressure drop so that the new number is X-Y pressure drop.  I think you have not modified your carbs, correct?  Therefore, it stands to reason that your lean issue has nothing to do with sprockets and more to do with your filter modifications which have increased air flow while leaving fuel levels unchanged.

In my business I also do a great deal of engineering with pulleys (in relation to fan speeds and outputs), sprockets are using that same basic science that governs pulleys.

I am not an expert on motorcycles (yet!), but I know a great deal about pressures, flows, and the relationships between the various factors that determine flow.  I don't know enough about how the air intake is affected by throttle to say for sure, but it seems to me that higher RPM would induce more air than lower RPM....therefore, running a "long" sprocket combination to reduce rpm would make the air flow less (if anything), thus making the mix in the carb richer...

I do follow what you are saying with the sprocket changes you have made, and even if I don't fully understand why you are doing it, it is interesting.

You pretty much understood what I tried to explain, and where more able to explain it than me, seeing your technical vocabulary in English is larger than mine.

There is one error in reasoning though;
At higher RPM, there is more airflow, thus also more air resistance with the stock filter.
More air resistance means more vacuum, thus more fuel from the jets goes in the mixture, and less air.
In other words, the mixture will run richer. With less airflow, there is less vacuum, thus less fuel in the piston, and more air, as it flows freer than fuel.
Lower RPM means running leaner for the same speed, as doing the same with high rpm.

You're right in the assumption that I haven't yet changed the main jet; it should still be pretty much stock, and it needs to be at least 5 sizes higher.

But thanks for the explanation; you're doing a better job than me in that field for sure 

[Suzuki Stevo]

You pretty much understood what I tried to explain, and where more able to explain it than me, seeing your technical vocabulary in English is larger than mine.

There is one error in reasoning though;
At higher RPM, there is more airflow, thus also more air resistance with the stock filter.
More air resistance means more vacuum, thus more fuel from the jets goes in the mixture, and less air.
In other words, the mixture will run richer. With less airflow, there is less vacuum, thus less fuel in the piston, and more air, as it flows freer than fuel.
Lower RPM means running leaner for the same speed, as doing the same with high rpm.

You're right in the assumption that I haven't yet changed the main jet; it should still be pretty much stock, and it needs to be at least 5 sizes higher.

But thanks for the explanation; you're doing a better job than me in that field for sure 

Fuel is drawn from the fuel bowl by the Venturi Effect, not vacuum.

[PantheraLeo]

Holy cow!

in plain English:   "It just don't work that way!"


Cookie

MeeLee, there is no "free flow filter", I believe you mean lower pressure drop filter.

Any filter, by definition has a pressure drop.  A zero pressure drop filter is doing zero filtration.  If the filter area is increased, the pressure drop associated with the filtration can be markedly reduced, but never eliminated.  There is always a pressure drop across any filter that has air moving across it.  You are correct that decreasing this pressure drop is frequently favorable to efficiency...but...if you are running lean, it is likely due to the fact that the carbs are designed for X pressure drop, and you have reduced the pressure drop so that the new number is X-Y pressure drop.  I think you have not modified your carbs, correct?  Therefore, it stands to reason that your lean issue has nothing to do with sprockets and more to do with your filter modifications which have increased air flow while leaving fuel levels unchanged.

In my business I also do a great deal of engineering with pulleys (in relation to fan speeds and outputs), sprockets are using that same basic science that governs pulleys.

I am not an expert on motorcycles (yet!), but I know a great deal about pressures, flows, and the relationships between the various factors that determine flow.  I don't know enough about how the air intake is affected by throttle to say for sure, but it seems to me that higher RPM would induce more air than lower RPM....therefore, running a "long" sprocket combination to reduce rpm would make the air flow less (if anything), thus making the mix in the carb richer...

I do follow what you are saying with the sprocket changes you have made, and even if I don't fully understand why you are doing it, it is interesting.

You pretty much understood what I tried to explain, and where more able to explain it than me, seeing your technical vocabulary in English is larger than mine.

There is one error in reasoning though;
At higher RPM, there is more airflow, thus also more air resistance with the stock filter.
More air resistance means more vacuum, thus more fuel from the jets goes in the mixture, and less air.
In other words, the mixture will run richer. With less airflow, there is less vacuum, thus less fuel in the piston, and more air, as it flows freer than fuel.
Lower RPM means running leaner for the same speed, as doing the same with high rpm.

You're right in the assumption that I haven't yet changed the main jet; it should still be pretty much stock, and it needs to be at least 5 sizes higher.

But thanks for the explanation; you're doing a better job than me in that field for sure 

Which part?  I'm not trying to challenge what you say, I just want to understand better.  The fuel is fed by gravity, yes?  By decreasing the size of the line, the velocity is increased at the jet, yes?

I'm very confident that my filter pressure drop portion is correct, but I'm unsure of the correlation between air flow and rpm and throttle "demand".  How does it work, exactly?

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