I may see if i can pick up a used carb and Bore it out, even a little should make a big difference as i believe the carburetor is one of the major limiting components at this time (Muffler is limiting too, but i want to stay with stock sound).

I think a 42 flat slide with pumper would be the kat's azz but i'm not tossing 500$ + on one.

Just another point of view; KLR650 CV carburetor vs Performance:
The KLR650’s 40mm KeiHin CV carburetor is very reliable and is more than sufficient to cater to most of the the KLR’s performance requirements. The carburetor by itself can support 327 CFM. It is the restrictiveness of air box that prevents full performance support.

The KLR in standard or in mild modified form does not benefit with performance carburetors such as the 40 mm Mikuni TM40-6 smooth bore or the KeiHin FCR. It is true that these carburetors can support a higher flow rate but since the the KLR cylinder head can only support 327 the higher flow performance carbs will have no additional advantage over the 40 mm CV carb.

Some feel that the accelerator pumps on theses carburetors will increase throttle response. We feel that the 40 mm CV carburetor with supporting modifications and correctly setup will be just as responsive.

Remove the KLR650 airbox from the equation and the it will benefit from these performance carburetors.

Full link: https://www.klrchris.com/kawasaki-klr650-airbox-mod/


Dave

Harley (and Kawasaki, on some Vulcan models) may have thought otherwise, installing 40 mm Keihin carburetors with accelerator pumps on their motorcycles.

Still, a minuscule perhaps, but inevitable, time delay exists between throttle opening and slide rising (a time interval defined in this post as, throttle response time) with a CV carb, even with a CV carb featuring an accelerator pump.

So, how significant is stock CVK40 throttle response time delay? And, how essential is throttle response time to KLR650 typical service life (as in, no competitive situation, ever)?

Hogging out the vacuum transfer port hole (to, 7/64" diameter) may improve throttle response, marginally. Again, how significant might such throttle response time improvement be? Stock KLR650 throttle response time may be acceptable, to some.

why lectron?
What do you get?

Simplicity: Lectrons have no jets and the least parts of any carburetor. They compensate automatically for a wide range of elevation and temperature changes which means less time fixing and tuning, and more time riding. We want you to forget you have a carburetor. The video above covers the basics of our metering rod carburetor technology.





Adjustability: Lectrons are the only metering rod fuel systems with two circuits. This means there are no harsh transitions compared to a jetted carburetor, while still having two independently adjustable circuits for bottom end and top end. This allows you to run leaner metering rods for crisp response off idle, while still making massive peak HP numbers. Have the bottom end perfect, but need more overrev to rip that holeshot? Going to ride a deep sand track and want to keep your top end cool? Simply adjust the external power jet screw.
Better Fuel Atomization: The fuel coming off the metering rod is in much finer particles than fuel coming out of a jet. This creates a much more efficient and even burn which helps make more power, use less fuel, decrease emissions, and help prevent fouling spark plugs.



The Best Throttle Response: The smooth, tapered bore design creates the fastest air speeds of any carburetor. Unlike a choked down keyhole design, our products are designed to flow the most air at the highest velocity. Lectrons are also the only carburetor with the fuel pickup tube always under vacuum (on the engine side of the slide). That means it is always full of fuel and adjusting float height for throttle response is a thing of the past.

https://www.lectronfuelsystems.com/kx-klr650-kits.html

Yikes! I clicked the link and saw $800. I'm way to cheap to shell out those kind of frogskins for a carb when I have a perfectly good one on the bike that can be significantly improved with a $50 KLX Jet Kit from Eagle Mike's. This is for the same reason I won't spent $500 for a cogent rear shock but I might happily spend $80 for a heavy duty rear spring from Top Gun. I love my KLR, but it's a KLR not a KTM.

Kev

I'll suggest that a Lectron carb still has 3 jets. The needle JET, which the jet Needle slides thru to vary the volume of fuel Available and the changeable 'power jet' which has a fixed maximum size.

Matching the varying taper of the needle to different engine components could still be a "fine art", imho.

And float bowl fuel level will still have an effect on its throttle response time, if ever so small!

And how can they 'compensate' for varying elevation & tempurature changes any better than any other carb? The three jets are still 'fixed' unless the owner, rider, mechanic physically alters them?

I am not saying that yours does not work Great, straight out of the box! Just sayin'.

What's the THIRD jet? I count only TWO, from your post!

i think he meant

needle jet
Jet needle
power jet

needle jet and jet needle make one jet to me, but thats just me, and am thinking that's how you're looking at it.

:P

I don't think most people could tell the difference between a properly jetted stock carb and the flat slide with a pumper.

still fun to think about, i'm wayyyy tooooo cheap to spend 800 on a carb too

PS i've been working lots but i have the o ring mod nearly done. Gotta lean out the needle more as the pilot jet overlaps into the needle effective range (which is normal). Then it should be perfect. and because of the larger pilot (with a leaner needle setting than stock (KLX needle)). The throttle response is wicked and no perceptible lag that most people would feel. You n i would, but we aren't most people.

Bikes are a bitch to Jet with ethanol Fuel, as you mentioned Damocles. The ethanol fk's up the plug color, makes it look lean when it isn't. I've had to adjust the way i do things, since what i used to do doesn't work the same. But fun figuring it all out.

Only reason i'm leaning the needle is to get the fuel economy better than stock. (only got 45 mpg at 75 miles an hour into a headwind half the trip) The bike runs fk'n deadly. Mega Mid range , fantastic throttle response.

I used to wrench a DRAG SNOWMOBILE that was a 1200 triple running lectron carbs. Nice carb but, too much $$$$ and i'm not sure its much better other than its simple and fast to tune.

Ok,
1/2 a jet & 1/2 a jet equals 1. But neither one works by itself does it?