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Discussion Starter · #21 · (Edited)
more preload would change the bottom half of the slide travel too much IMO

same preload with a stiffer rate would be what I'd be after, i have a Harley spring here i might look at one of these days

basically what i'm saying is the slide hits the top ever so slightly too soon.

a person could theoretically, stretch 1/3-1/2 of the spring (widen the coils on 1/3-1/2 of the spring), then trim it back to OEM free length, and have EXACTLY the right progressive rate. I might try it sometime.


I think that would be more initial preload with the same spring Rate. Don't encroach upon the vacuum hole with your washers, they would need to be quite narrow.
 

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you know , and you DO know, its a big single.

I THINK TORQUE. Horsepower is an afterthought. its a big single , to me this goes without saying, each to their own though.

in the rev range one rides, for me 2500-5000 rpm, the torque is much higher than the Horsepower., Horsepower is useful from about 5600 to 6500 ish on the klr 650 (unless you're in top gear)

i only do those runs for testing. Unless i'm on the highway i run 2500-3800 when possible. As it should be.

RPM is across the bottom. (typical dyno chart, this is in a stock machine with the snorkel out. thats it. IIRC

View attachment 30763
taking the above into account, consider the rotating mass. It applies to anything that spins including wheels and crankshafts etc

the KLR has decent size flywheels, then add the rotating mass of the counter balance system, the weight is something you have to work with. AKA torque. well ... and the lack of RPM the KLR is capable of ...

the POWerbomb plays into this. and works excellent with the stock muffler.

it also acts like a pre muffler like David mentioned. You can be super stealthy with it.

the back pressure with the OEM muffler combined with a power bomb header and the mcp kit is the shizzle. really nice.

Carburetion that PLAyS on the torque is key.

its funny, i get 45 ish mpg US now at 75 mph lol (no wind, flat ground)

keep in mind i'm also about efficiency. The 2014.5+ (maybe 2012+) muffler seems to flow better compared to prior years
Interesting belief system; not sure everything mentioned comports entirely with the Laws of Motion. Yet, said laws were once challenged on a now-defunct (?) KLR forum (not, ".net")..

Significance: None Those guys ignored/rejected particularly the Law of Inertia, insisting a KLR requires two horsepower to rotate the balancer. Come to think of it, they rejected the Second Law (Force) in rotational context as well.
 

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Discussion Starter · #23 ·
from wikipedia
In physics and mechanics, torque is the rotational equivalent of linear force.[1] It is also referred to as the moment, moment of force, rotational force or turning effect, depending on the field of study.

Inertia is the resistance of any physical object to any change in its velocity. This includes changes to the object's speed, or direction of motion.

the rotational mass of an object is a description of how easy or difficult it is to rotate a body or to stop it once it is rotating.

the inertia, rotating mass, Torque, are all relative

so i'm a bit confused how i'm ignoring physics principals,

Interesting belief system; not sure everything mentioned comports entirely with the Laws of Motion. Yet, said laws were once challenged on a now-defunct (?) KLR forum (not, ".net")..

Significance: None Those guys ignored/rejected particularly the Law of Inertia, insisting a KLR requires two horsepower to rotate the balancer. Come to think of it, they rejected the Second Law (Force) in rotational context as well.
 

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Discussion Starter · #24 ·
Professional tuners use the engine characteristics to determine where to focus their efforts when creating power. Sometimes horsepower is the primary consideration, sometimes the torque is the primary consideration.

in the case of the KLR torque should be the main goal determined by the design of the engine. Limited rpm range, single cylinder, large rotating mass.

Example the Honda 400 4 cylinder, it would be ridiculous to try to get torque out of a 400 4 cylinder high rpm machine. The low RPM KLR being a big single should be about torque, is all i'm saying.

should be common sense.
 

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High rotating mass does not necessarily limit engine RPM. Consider the rotating mass in a CBX or a jet turbine. High reciprocating mass limits RPM, especially in long stroke engines. As in a KLR. So, yes, it should be developed for low to mid-RPM torque.
 

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Discussion Starter · #26 · (Edited)
i think the terminology you're eluding to is piston speed and piston acceleration. agreed. these are the things that limit RPM

the heavy rotating mass once moving has a lot of inertia, which works best with torque not HP was what i was saying

What surprises me is no one even mentions torque, even when dyno runs are performed.

to me torque is #1, HP#2


High rotating mass does not necessarily limit engine RPM. Consider the rotating mass in a CBX or a jet turbine. High reciprocating mass limits RPM, especially in long stroke engines. As in a KLR. So, yes, it should be developed for low to mid-RPM torque.
 

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more preload would change the bottom half of the slide travel too much IMO

same preload with a stiffer rate would be what I'd be after, i have a Harley spring here i might look at one of these days

basically what i'm saying is the slide hits the top ever so slightly too soon.

a person could theoretically, stretch 1/3-1/2 of the spring (widen the coils on 1/3-1/2 of the spring), then trim it back to OEM free length, and have EXACTLY the right progressive rate. I might try it sometime.
Grant,
Didn't you at one time suggest that the OEM mid-range jet needle 'Prevented' the vacuum diaphragm operated throttle slide from opening the carburetor bore completely? And I asked 'how'.
 

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Discussion Starter · #28 ·
correction - i said stock jetting can't hold wide open throttle. Nor can the other carb kits i have experience with, other than MCP

a mixture TOO FAR from ideal makes a lot less than normal amount of vacuum

the slide is vacuum operated. as you know, so it will drop and not hold WOT


Grant,
Didn't you at one time suggest that the OEM mid-range jet needle 'Prevented' the vacuum diaphragm operated throttle slide from opening the carburetor bore completely? And I asked 'how'.
 

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Discussion Starter · #29 ·
i've seen a lot of KLR dyno charts in the last few years i've been doing MCP

Half of them don't even have the torque curve on the chart

Soo many turners only see max HP and tune for that, Thats BASS ACKWARDS with regard to the KLR is all i'm sayin.
 

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Discussion Starter · #30 ·
Paul, if you had it in your bike, you wouldn't question it, jus sayin.

no matter how well you think its running, and i'm sure it runs good, it can run twice as good. Using any metric you wish to apply
 

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Discussion Starter · #31 ·
vacuum lvl compared to butterfly position is key
 

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. . . stock jetting can't hold wide open throttle.
Like pdwestman, I wonder . . . why not?

I thought the slide of a CV carburetor rose as a function of the pressure differential ("vacuum") between the venturi and vacuum chamber.

Since the force of the pressure differential ("vacuum") results from the fluid (air flow) velocity in the venturi, how does the MCP kit increase the pressure differential ("vacuum") from stock configuration, between the venturi and the upper diaphragm surface (lower diaphragm surface vented to atmospheric pressure)?

Just wondering how a jet kit alone might affect Mr. Bernoulli's discoveries.
 

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Discussion Starter · #33 · (Edited)
There are a few vacuum zones in the venturi that affect how a CV functions,

vacuum in front of the butterfly
the vacuum between the butterfly and slide
vacuum above the slide diaphragm

the vacuum in front of the butterfly is directly related to how efficient the carburetion is

the slide rising has to do only with air flowing under the slide, causing a vacuum above the diaphragm which raises the slide.

the air flowing under the slide also pulls fuel from around the needle and nozzle

the difference in pressure above the slide diaphragm (sealed chamber) and below the diaphragm which is the same pressure as the air box between the air filter and the carb, is responsible for the slide moving

if the carburetion is too inefficient, the vacuum isn't as high as it should be and the slide drops more than it should between intake pulses and doesn't hold maximum slide opening. (This is the carb "SELF ADJUSTING")


I thought the slide of a CV carburetor rose as a function of the pressure differential ("vacuum") between the venturi and mixing chamber.

Since the force of the pressure differential ("vacuum") results from the fluid (air, mixture) in the venturi, how does the MCP kit increase the pressure differential ("vacuum") between the venturi and the underside of the diaphragm?

Just wondering how a jet kit alone might affect Mr. Bernoulli's discoveries.
Like pdwestman, I wonder . . . why not?

I thought the slide of a CV carburetor rose as a function of the pressure differential ("vacuum") between the venturi and vacuum chamber.

Since the force of the pressure differential ("vacuum") results from the fluid (air flow) velocity in the venturi, how does the MCP kit increase the pressure differential ("vacuum") from stock configuration, between the venturi and the upper diaphragm surface (lower diaphragm surface vented to atmospheric pressure)?

Just wondering how a jet kit alone might affect Mr. Bernoulli's discoveries.
 

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There are a few vacuum zones in the venturi that affect how a CV functions,

vacuum in front of the butterfly
the vacuum between the butterfly and slide
vacuum above the slide diaphragm

the vacuum in front of the butterfly is directly related to how efficient the carburetion is

the slide rising has to do only with air flowing under the slide, causing a vacuum above the diaphragm which raises the slide.

the air flowing under the slide also pulls fuel from around the needle and nozzle

the difference in pressure above the slide diaphragm (sealed chamber) and below the diaphragm which is the same pressure as the air box between the air filter and the carb, is responsible for the slide moving

if the carburetion is too inefficient, the vacuum isn't as high as it should be and the slide drops more than it should between intake pulses and doesn't hold maximum slide opening. (This is the carb "SELF ADJUSTING")
Mr. Clymer describes slide and jet needle rising in somewhat different syntax:

""During operation, when the throttle valve [butterfly] is opened, air demand and speed through the carburetor is increased. As air passes under the slide, air pressure drops in that area [q.v., Venturi effect, Bernoulli principle}. This low air pressure is vented to the upper diaphragm chamber. The lower diaphragm chamber is vented to atmospheric pressure. This difference in pressure causes the slide and jet needle to rise, allowing fjuel to pass into the carburetor throat. When the throttle valve is closed, the pressure differential lowers, allowing the slide and jet needle to return to a resting position."

Still don't see how MCM alternative jetting alone surpasses stock venturi air flow velocity, increasing pressure differential ("vacuum") and consequent slide lifting force. Probably, that's just ME! :)

If the MCM jetting alone increases intake air velocity, permitting slide elevation to the physical mechanical limit, while the stock CVK40 jetting does not, congratulations on your invention/discovery. Kawasaki and Keihin might be interested in licensing, I should think..
 

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POWER BOMB HEADER + Stock Muffler + mcp + snorkel yank

It has a wee bit better BRAPP from the exhaust when you walk on it but it is quieter while cruising due to the less amount of throttle input required to maintain speed.

Its soo fantastic, i would have never guessed. If you understand exhaust pulse waves this only makes sense, I just underestimated how well it would work with the stock muffler.

I theorize that putting this header on with an open unrestricted exhaust would yield LESS GAINS (or without mcp carb kit). That is just me thinking out loud though. (quiet tips and spark arrestors would regain some backpressure). As everyone knows open exhaust is more for creating HP, but the KLR is better at makin torque. (similar to the harley V twin) It is a big single after all, torque is what it was made for.

I have about 400 miles on this new set up. Couldn't be more surprised & pleased but i'm after torque and efficiency, most seem to be after horsepower.

It actually vibrates a hair more due to the stronger, crisper, power stroke (more torque). Thank god mcp reduced the vibes long ago when I put it in. (And this is true, regardless if you believe it or not)

Photo for effect
View attachment 30694
I did the MC mod and noticed similar results. More of a braPP than brap and more vibration. Feels way torquier. So Grant do you think the Powerbomb would work with the MC mod, L mod Uni Filter, Glass pack and what MCP setup would you recommend for that. I'll probably be doing a 685 in a year or two so what would I change when I do that. I'm really torn between the easy route with the MCP kit and going flatslide. I hate vacuum carbs and the vulnerable diaphragm. They were a forever problem on my XS before I heaved them for flatslides. It's less of an issue with the KLR's single carb. Even the older cable round slides don't have a diaphragm to dryrot.
 

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I did the MC mod and noticed similar results. More of a braPP than brap and more vibration. Feels way torquier. So Grant do you think the Powerbomb would work with the MC mod, L mod Uni Filter, Glass pack and what MCP setup would you recommend for that. I'll probably be doing a 685 in a year or two so what would I change when I do that. I'm really torn between the easy route with the MCP kit and going flatslide. I hate vacuum carbs and the vulnerable diaphragm. They were a forever problem on my XS before I heaved them for flatslides. It's less of an issue with the KLR's single carb. Even the older cable round slides don't have a diaphragm to dryrot.
I'll let Grant comment on his kit questions. As far as carb swaps; I have the original diaphragms in my 2000 and 2001 and they work perfectly with no sign of rot. Furthermore, those in the know opine that there is no power difference in a carb swap on a stock or mildly modded KLR and the stock CVK is largely self adjusting for altitude which makes life easier. Some people think suspension mods are too expensive or a silencer is a waste of money but I'll put carb swaps WAY ahead on the "waste of money" list.

2 cents,
Dave
 

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Discussion Starter · #37 · (Edited)
Damocles

it says the same thing i do.

the part you may be unclear on is, your clymer suggests fuel doesn't flow from the needle until the slide lifts, not true, once enough air is moving below the slide fuel starts drawing, before the slide even moves.

says the same thing with different wording, you trying to start a fight over nothing or?

and you know DAMN well its "MCP", stop being deliberately obtuse or i'll start calling harassment Damocles. GROW UP already ... jesus


Mr. Clymer describes slide and jet needle rising in somewhat different syntax:

""During operation, when the throttle valve [butterfly] is opened, air demand and speed through the carburetor is increased. As air passes under the slide, air pressure drops in that area [q.v., Venturi effect, Bernoulli principle}. This low air pressure is vented to the upper diaphragm chamber. The lower diaphragm chamber is vented to atmospheric pressure. This difference in pressure causes the slide and jet needle to rise, allowing fjuel to pass into the carburetor throat. When the throttle valve is closed, the pressure differential lowers, allowing the slide and jet needle to return to a resting position."

Still don't see how MCM alternative jetting alone surpasses stock venturi air flow velocity, increasing pressure differential ("vacuum") and consequent slide lifting force. Probably, that's just ME! :)

If the MCM jetting alone increases intake air velocity, permitting slide elevation to the physical mechanical limit, while the stock CVK40 jetting does not, congratulations on your invention/discovery. Kawasaki and Keihin might be interested in licensing, I should think..
 

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Discussion Starter · #38 · (Edited)
I was skeptical of the MC mod, assuming you're talking about advancing the exh cam a tooth, i'm less skeptical now. The KLR for a low revving engine has A Lot of valve overlap... Valve overlap helps HP more then torque. The MC mod should reduce teh valve overlap and be more torquey for sure. I've not done it myself but the theory stands and should work right into what the powerbomb is supposed to do. A quiet tip on that glass pack would help torque more yet as straight through exhausts help HP more at the expense of torque.

MCP kits are based on air box and exhaust mods. so you'd pick the 'Modified air box + Aftermarket Exhaust" kit.

If you do flatslide go 42, no sense putting a 40 flatslide on imo.

Diaphragms last a long long time in a properly running bike as a rule. the only real danger is a big backfire popping it during a tip over.


I did the MC mod and noticed similar results. More of a braPP than brap and more vibration. Feels way torquier. So Grant do you think the Powerbomb would work with the MC mod, L mod Uni Filter, Glass pack and what MCP setup would you recommend for that. I'll probably be doing a 685 in a year or two so what would I change when I do that. I'm really torn between the easy route with the MCP kit and going flatslide. I hate vacuum carbs and the vulnerable diaphragm. They were a forever problem on my XS before I heaved them for flatslides. It's less of an issue with the KLR's single carb. Even the older cable round slides don't have a diaphragm to dryrot.
 

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Damocles

says the same thing with different wording, you trying to start a fight over nothing or?
First, profound and sincere apologies for mis-stating the name of your product(s); I'll try to remember, MCP, from now on. Senility is CRUEL!

Mr. Clymer didn't mention the aspects you mentioned, the various "vacuums" affecting CV carburetor operation:
-------------
vacuum in front of the butterfly
the vacuum between the butterfly and slide
vacuum above the slide diaphragm
____

Instead, Clymer says only the venturi airflow velocity creates a pressure differential, routed to a vacuum chamber, where atmospheric pressure against the diaphragm lifts the slide.

You posted your MCP (See? I got the nomenclature right, this time!) jetting creates greater slide opening force than stock jetting, opening the slide fully whereas the stock configuration cannot. I wondered how your MCP jetting increases airflow velocity beyond a stock CVK40's, and thus increases the pressure differential ("vacuum"), providing additional force raising the slide.

Please disregard if my question is inappropriate and/or stupid; probably both! :)
 

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Discussion Starter · #40 ·
The Clymer obviously gives basic information only.



First, profound and sincere apologies for mis-stating the name of your product(s); I'll try to remember, MCP, from now on. Senility is CRUEL!

Mr. Clymer didn't mention the aspects you mentioned, the various "vacuums" affecting CV carburetor operation:
-------------
vacuum in front of the butterfly
the vacuum between the butterfly and slide
vacuum above the slide diaphragm
____

Instead, Clymer says only the venturi airflow velocity creates a pressure differential, routed to a vacuum chamber, where atmospheric pressure against the diaphragm lifts the slide.

You posted your MCP (See? I got the nomenclature right, this time!) jetting creates greater slide opening force than stock jetting, opening the slide fully whereas the stock configuration cannot. I wondered how your MCP jetting increases airflow velocity beyond a stock CVK40's, and thus increases the pressure differential ("vacuum"), providing additional force raising the slide.

Please disregard if my question is inappropriate and/or stupid; probably both! :)
 
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