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New Carb Setup - Loving it!

33K views 134 replies 20 participants last post by  Sammy_Groover 
#1 ·
Got the carb kit below and installed it on my 2014.5 KLR. I had upgraded to the EM KLX kit last year, and while I loved it over stock, still wasn't totally happy and wanted better gas mileage. Below are some findings from a 43 mile mixed (dirt and pavement) ride today.

I plan on putting more miles on soon (and really look forward to it [emoji846]). I think this guy was on the forum a while back while he was developing his needle, etc. Per an agreement with him, due to the newness of his kit, I'm not able to share hardware specifics, but happy to share my "seat-of-the-pants" riding impression.

Please know, I'm not like many of you on here that are great mechanics and have wonderful engineering minds. I'm an old farm boy that loves riding and tinkering with my bikes. I have learned and implemented many things from you all and just wanted to share what I see as a very positive upgrade for my beloved KLR. YMMV and I'm not claiming to be an expert, just one happy KLR rider thanks to this kit.

https://www.facebook.com/pg/LloydminsterSmallEngine/photos/?tab=album&album_id=760397424427861

Impressions from my ride today:

1. Very smooth power delivery in all ranges
2. Power always on tap and ready when you need it.
3. Pulls hard and smooth without any hesitation in all typical RPM ranges.
4. Crisp throttle response throughout power band.
5. Better off-road experience overall due to better throttle response (no bogging down in higher gears and ready to pull if needed).
6. More predictable at slower speeds (off-road is great!) due to no lagging or hesitation.
7. Filled up before and after my ride and happily report 46.1 mpg (US gallons). Didn't baby it at all and hit 70 several times (on pavement [emoji846]).
8. Overall RPM's seem lower at all speeds and engine seems calmer. Around 4700-4800 RPM at 70 (from GPS) with a 16 tooth front sprocket.
9. As peppy as the KLX needle (read that fun), but more control, response and better MPG (was getting 43 MPG on that needle at best).

Just wanted to share my good news and not looking to debate any aspect of this. I am just choosing to enjoy it and "ride it like I stole it" LoL

Sent from my SM-G965U using Tapatalk
 
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#64 ·
I'll suggest that we all ought to just kick back, relax and give the purchasers of this new carburetor re-jetting kit a chance to be thoroughly tested.

The proof is in the puddin' they used to say.
 
#67 ·
I'm kinda interested in this. I agree with the observations about the KLX kit. It's kinda beastmode and I'm on the clutch at lower speeds. I like beastmode but it doubles my consumption of chains and rear tires. Cars routinely get better milage. Lacking a multi million dollar facility with a closed course, air tunnels etc most of us only have a butt dyno to go by. I'm pretty sure the market for $55 klr needles isn't lucrative enough to afford much more than a 6pack. It sounds like he might be on to something with this. By tapering the needle in all the right places these things should be possible. I'm also interested in this O ring thing he's come up with. The KLR is anything but the model of efficiency.
 
#68 ·
I like beastmode but it doubles my consumption of chains and rear tires.
"CRAZY Power" was claimed by the developer/marketer on ADV. (Possibly might cause additional chain and rear tire wear.)

If correct, if discoveries unknown over three decades of CVK40 tuning were uncovered and are fulfilled by the kit, then, rightly . . . the world should beat a path to the innovator's door; he should prosper from his initiative and innovation. Greater power, increased fuel mileage. Beneficial to all users.

Please post your perception and experience with your kit, Hvymax, as did Sammy_Groover. Haven't heard from DirtyDanTX yet.
 
#69 ·
Working 60+ hr weeks for the foreseeable future. It's all I can do to keep up with basic maintenance and work a few trails into my route. I can see the science of it and consider it feasible. I might try to work it in when this project winds down between getting my SCWI and doing the TAT. No rest for the wicked.
 
#70 ·
The KLX kit was a game changer for my bike. If he can refine it further to address some of the shortcomings it's a beautiful thing. Kina like the old Holly's etc. You could set them up for one thing and everything else sucked. Then came Predators with the variable venturi. Carb tech has all kinds of possibilities but there have always been snake oil salesmen as well. If I see a few more positive reviews I'll probably considered this when time allows.
 
#75 ·
I installed the KLX needle and 140 main jet and opened the idle mixture screw a bit and removed the snorkel on my 2017.
My KLR used to lightly surge between 20 and 40 kmh under light throttle with the stock jetting.
This surging is almost gone with the KLX parts installed but at 20 kmh it still surges a little bit in the lower gears.
I suspect that the mixture is still a bit lean in the zero to quarter throttle range.
If I'm not mistaken the mixture quarter throttle or less is controlled mostly by the pilot jet and needle taper.

I really don't see where any extra power will come from from a mixture adjustment. The factory and KLX settings are
not so far off as to cause a power loss.
 
#77 · (Edited)
@AFMoulton,

No.

What you are asking me to do is spend $250 and a bunch of my time to prove that you can't have improved throttle response, improved fuel economy, increased power, and increased torque all at the same time, which is essentially what Grant Jenson is saying his needle does do. He has never presented a theory of operation that would change that claim. He has, in fact, reiterated that claim in the quote above, to wit: "fuel economy near stock value but with more power than the KLX".

To take up your challenge would be a fool's errand.

Look, I have been playing with CV carbs for about 50 years. That doesn't make me any kind of expert because I don't/didn't do it on a daily basis, but I think I do know shit from Shinola. If he was to come out and explain what he's done and how it works (raise the slide a bit to give it a headstart on airflow, fattened up the needle at low throttle position to lean the mixture and improve throttle response, thinned out the top end to improve power, average combined city/highway mpg is good due to leaner low end, yadda yadda) instead of flinging poo I think that would be great. Instead, he chooses to market with snake-oil. That sets off my BS detector and tells me that he can't sell the thing for as much as he does based on facts and data. If you can't sell something based upon the facts and data, then it is questionable that it is worth what you're spending.

Let's put it another way. Would you spend $50 to gain 1.5hp at a point on the power curve that you don't operate at and have less power at the point that you do operate at? That's what the dyno chart shows; those are the data.

If you would do that, just stay with the stock needle and put an o-ring on your slide. The stock needle is pretty lean at low-to-mid throttle; you'll have good throttle response and decent fuel economy. You don't operate much at 6K+rpm, so you won't miss the added 1.5hp.
 
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#89 ·
Thank you for the o-ring information.

Owing to the poisson effect, the effective height of the o-ring after installation will be somewhat less than 0.10", but it still represents a significant change in the vacuum piston elevation and, thus, the needle elevation, assuming that the diaphragm retainer acts as a positive stop for the vacuum piston.

It appears that this o-ring spacer is needed to raise the needle because there are no other means, ergo grooves in the needle, to raise it. And without raising the needle, the mixture will be too lean off idle.

I am open to further discussion on the purpose of the o-ring.

Jason
 
#87 ·
I put 92 miles on the KLR in the last couple days and filled up the tank.
It took 2.1 gallons to top it up. That works out to 43.8 miles per US gallon.
This was mostly driving around town lots of stop start in traffic driving.
Before I installed the KLX parts I calculated my mileage with the factory jetting to be 47.5 miles per gallon over two tanks of fuel.
After I installed the KLX parts I calculated 46.6 miles per gallon on the next tank so no real difference.
Keep in mind that I was a bit heavier on the throttle than normal testing out the power increase so that may have dropped it a bit.
So again no real change.
 
#95 ·
The o-ring would raise the slide and the needle.

Raising the slide increases the volume of the venturi (more correctly, perhaps, its cross-section). That reduces air velocity for a given vacuum (loosely correlated to the opening of the throttle plate).

If we raise the slide and the needle, pulling the needle out of a huge jet (but the cross-section of the needle is unknown) and let some air flow slower over the needle jet that protrudes into the venturi, it should be obvious to the thoughtful student what happens.

Me, I got nuthin'. No idea. Standing here with my pee-wee in my hand. We have an equation with five variables and five unknowns.
 
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#96 ·
Raising the slide increases the volume of the venturi (more correctly, perhaps, its cross-section). That reduces air velocity for a given vacuum (loosely correlated to the opening of the throttle plate).

If we raise the slide and the needle, pulling the needle out of a huge jet (but the cross-section of the needle is unknown) and let some air flow slower over the needle jet that protrudes into the venturi, it should be obvious to the thoughtful student what happens.
It's kinda like two things at odds are happening at once, right? Air velocity goes down, which diminishes the tendency to suck fuel up, but fuel availability goes up, which tends to make the most of whatever suction there might be.

I suppose we'll just have to each install it and judge if it sucks, more or less, each for our own selves :25a:
 
#100 ·
Ok I'm not Tom and I don't look pretty in pink.

But here are my dialed-in mods:

    • KLX needle
    • Clip positioned 2nd from top
    • 0.013" thick washer installed beneath clip (hand lapped on the thigh of a virgin)
    • 140 main jet
    • 40 pilot jet
    • Pilot jet needle 2 turns out
    • Snorkel removed from air box
    • 1-inch holes drilled on top of dirty side of air box
    • Go-fast air filter
    • exhaust cam advanced one (1) tooth

Jason
 
#103 ·
I am very interested in the effect advancing the cam has on performance.
I will be checking and probably adjusting my valves this winter and would consider advancing the exhaust cam.

Terry
After advancing my exhaust cam one (1) tooth I could not "feel" any difference whatsoever. That's not to say there isn't any performance improvement, but I simply do not have the means to measure such small changes.

While we're on the topic of engine modifications, I think some folks perceive significant improvements in performance after making modifications when in reality there is minimal or no improvement. What's more, I think there is often a direct relationship between $$$ spent on the modification and the perceived benefits. :wink2:

Jason
 
#102 ·
My engine is set up with a Wossner 11:1 piston, a ported head with big valves, an airbox with four 1" holes, and holes in the top half of the airbox door. The muffler is from a GSXR750.
I also have modified the valve timing. Intake has been advanced 4 degrees, the exhaust has been advance 6 degrees.

The carburetor is set up with a #42 idle jet and a 145 main. The needle is on the second clip. I set the idle circuit to an AFR of 14:1. The main circuit runs at 13.5:1 at the lower end, returning to about 13:1 at around 6000rpm. AFR was checked with an Innovate LM-2 wideband O2 analyzer.

I haven't hooked the O2 analyzer up in quite a while, probably should just to see how it is running.
 
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