Kayfun V4 Clone Review

Header photo

Robbot Tech Kayfun V4 Clone Review

The Kayfun rebuildable atomizer series made by SvoeMesto is not only the most popular, and most imitated bottom coil style atomizer that this market has seen within the last year and half, it is also the most influential. From the Squapes, to the Orchids, Erls and Lemos, even as these rebuildable atomizers have qualities and design elements that make them unique unto themselves, they all find their foundation in the Kayfun style. The genius of creativity is not found in originality, as much as it is in the brilliance of reinvention.

With the coming of the new SvoeMesto Kayfun V4, we see a complete reinvention of the Kayfun style atomizer bearing very few design and engineering elements of the original Kayfun style. The Kayfun V4 brings with it a new body style which includes a glass tank option, a new build deck, redesigned juice feed/juice control, an adjustable 510 pin and a lot more parts and pieces — arghhh.

What I find most interesting as well as very suspicious is the fact that the clones of the new Kayfun V4 atomizer were well into production by the time the first authentic SvoeMesto Kayfun V4 was made available for worldwide sale. How was that even possible? There were many who in error thought that the Kayfun V4 was too complex to be cloned, let alone that it would happen the same week that the authentic Kayfun V4 was released. If we have learned anything, it should be to never underestimate China because their hustle is real folks.

The Kayfun V4 clone featured in this review is made by Robbot Technology, and was provided for the purpose of this product review. The Robbot Tech Kayfun V4 was intended to be a 1:1 replication, and is packaged in a cloned SvoeMesto gift box which includes the Kayfun V4 clone atomizer, a glass tank, a polycarbonate tank section, full user manual, and a parts and assembly demonstration sheet.

[box type=”shadow” align=”aligncenter” width=”600″ ]

Where to Buy a Kayfun V4 Clone

[/box]Collage 1


  • Brand: Robbot Technology
  • Type: Rebuildable bottom coil atomizer
  • Material: 304 grade stainless steel
  • Connection threading: 510
  • E-liquid capacity: 3.5-4.5 ml
  • Diameter: 22mm (base) 23mm (body with SS and Glass tanks)
  • Height: 77.7mm
  • Weight: 104 grams


  • Liquid control
  • Top filling capacity
  • Airflow control
  • Quad pole deck design
  • Adjustable 510 connector
  • Removal of deck without draining the tank


Being that Robbot Technology had previously cloned the ZNA 30 using 316L stainless steel, I think that many, including myself had expected the same for their Kayfun V4 clone. However, that is not the case. This 1:1 Kayfun V4 is made from 304 grade stainless steel, which is not an inferior grade of steel as much as it an easier to machine and mass produce grade of stainless steel.

Upon initial inspection out of the box I was happy with the way this clone looked, and the weighty feel of it. At 104 grams it is about 8-14 grams heavier than the prior Kayfun 3.1 ES and Lite versions. The Kayfun V4 also has a totally different aesthetic from the prior Kayfun versions. The top cap design is the only aspect that remains reminiscent of the original Kayfun style. There is now a laser engraved SvoeMesto logo on the middle tank section at the center of an engraved diamond shape. There is also a new 3D engraved SM logo on the front of the outer belt of the threaded chimney bell.

Based on photos, as well as statements from the owners of the authentic Kayfun V4, the engravings on the Robbot Tech clone are not as deep as the authentic, but are nicely done none the less.

Collage 2

During the early days of the pre-release of the Kayfun V4 there was lots of awe regarding the seemingly daunting 41 part assembly of this reinvented Kayfun, which also applies to its clone. However, the most basic parts breakdown into 10 pieces, which is still a lot more pieces than we usually see on a RBA/RTA. The 10 basic parts that make up this atomizer clone are all well machined. The threads were all smooth, and all parts threaded together easily, although the bolt that holds the middle and upper tank segment together was installed very tightly. I actually needed pliers to remove it initially.

It is not necessary to break this atomizer down into it 41 parts in order to clean or use it. But if you do, then I suggest that you have the parts and assembly guide on hand while you do so. This atomizer did smell of machine oil when I received it however, it wasn’t anything that a 10 minute cleaning couldn’t fix.

Now looking at these parts you can see how much of a departure there is from the prior Kayfun style design, for which I will cover all of the essentials in this review.

Collage 3


The only aspect of the new deck design that remains similar to the prior versions are the positive and negative blocks. At first look the decks construction appears to be solid although the positive looks lightly chewed around the edges, so I was not impressed with that. The four catch screw design may lead some to believe that is atomizer was intended for dual coil configurations however, that is not the case. The purpose of the fours screws is to add more options for installing and positioning your single coil.

On the upper deck there are two counter sunk e-liquid holes on either side of the center block where your wicks will sit. The air flow hole at the center of the deck appears to be a little larger than some of the other V4 clones on the market.

Collage 4

Now the air flow hole at the center of the deck is fed through the four air holes around the part of the device that SvoeMesto refers to as the UC connector. However, the degree of air flow into the atomizer is controlled by an air flow screw which can only be accessed by removing the adjustable 510 connection as shown below.

The 510 pin is installed with an insulator surrounding it to prevent shorts. Once removed, you can access the air flow control screw which you will need a flat head screwdriver in order to adjust. If making the adjustment from the position shown in the photo below, you would turn the screw clockwise to close, and counter clockwise to open. Now here is one place that some of the new design elements can be seen as an annoyance. That is a good bit of work to do in order to adjust air flow to your liking.

While reviewers such as Phil Busardo felt it was not a big deal to just set the air flow once to taste and forget about it, this is not necessarily the reality of how some of us vape. And considering Phil’s favorable comments regarding the tool-less adjusting of the new Russian 2.0 atomizer, I was surprised that he didn’t take some issue with this “tool and work required” airflow control system of the Kayfun V4.

Some of us like to tailor air flow according to our builds and e-liquids which can change, and in which case this style of air flow control can be a PITA. So how you get on with this air flow adjustment system will depend on whether you are a “set it and forget it” vaper, or the “adjust airflow to suite different builds with different e-liquids” vaper.

Collage 5

The stainless steel spring under the deck is thick and stiff, and it has not caused any issues with the resistance of my atomizer changing, as I have heard reported by some owners of the authentic Kayfun V4. As I get to the juice control mechanism of this atomizer clone, this is where I find my one and only real issue with the build quality on the Kayfun V4 clone that I received.

Out of the box my juice control was very difficult to move. Once I was able to muscle the deck up and out of the “UC upper section”, the o-ring #16 was a little frayed as though it was smashed by too much friction. So initially I thought the o-ring was too big, and I changed it out for a thinner o-ring from another atomizer.

That seemed to help a little, but not enough to make adjusting the JC easy. My guess is that the size and tolerances on this particular part of my atomizer are off. I have spoken to, and read the comments of a few other owners of the Robbot Tech Kayfun V4, and this is not an across the board occurrence, yet is has been reported on a couple of them. Youtube reviewer Richard Ng also reviewed this particular clone, and his juice control works smoothly.

In the photos below you can see what the deck looks like when the juice control is in the off position (top right), and in the open position (bottom right).

Collage 6


Even as there are now 4 catch screws instead of 2 on the build deck, the act of building a coil on the Kayfun V4 remains the same. I used 27 gauge Kanthal to make a 9/10 wrap on a 2mm screwdriver, which metered out to 1.5 ohms. As per SvoeMesto, the Kayfun V4 was not intended for sub ohm builds, and it is recommended that you do not build below .8 ohms if you are using the standard kit/insulator. SvoeMesto, does offer a 4s sub ohm upgrade kit for after market sale. I am also aware that Tobeco is now producing a 4s sub ohm as well.

Installing a build on this deck is not more difficult, or easier with the new wider positive/negative block and 4 catch screw configuration. Wicking is also the same, I used the same amount of cotton wick as I have with previous Kayfun versions. You should also continue to prime your wicks with e-liquid prior to filling your tank.

Collage 7

The first time that I went to reassemble the Kayfun V4, it took three tries before I got it right. First I forgot to install the chimney bell, and installed the bottom tank section first, lol. Then I put the entire tank together, including the bolt that holds the tank sections together, when I realized that I forgot to install the deck sleeve — Oy vey.

I do not like how much work is involved in changing from the stainless steel tank, to the glass tank, most especially due to the bolt/nut which has a lot of threads. A quick change between tanks is out of the question here. With glass kits being a popular after market accessory for the prior versions of the Kayfun, I would have liked to have seen a more simple, yet effective glass tank design with the new Kayfun V4.

Collage 8

To be the best of knowledge the juice control system of the new Kayfun V4 has two settings, off and on. Being able to turn the juice flow into the tank off, also allows the user to be able to top fill the Kayfun without the risk of forcing e-liquid into the deck chamber when the drip tip adapter is installed to the top cap after filling.

If you look closely at the threading on the drip tip adapter in the photo below, you will notice the flat section of the threads which will allow air to escape from the tank when the adapter is installed after filling. This is to prevent air from being pushed into the tank which would cause flooding.

Being that the juice flow control on the Kayfun V4 clone that I received is very stiff, top filling this device has been anything but a pleasure for me. Even as I feel SvoeMesto’s Kayfun V4 design is overly complicated, having incorrect build tolerances around my juice flow control is the fault of Robbot Tech. The fault of this one aspect of the device really did bring down my ability to enjoy this atomizer.

Between the new juice control, air flow control, and the difference between how each tank assembly affects juice feed into the deck, I had to do a lot of adjusting, and fiddling in order to get this atomizer to a place where I could enjoy its performance. While I have not experienced any leaking, I did experience some gurgling specifically when I had the air flow set a tighter setting with Max VG juice. It sounded like breathing through a nose filled with mucous.

When set up in the SS or Glass tank configurations with max VG liquid, and a very open air flow, I did experience dry hits while chain vaping. This is an issue that I have never had with any Kayfun atomizer. The flavor production was also muted in comparison to atomizers like the Rose or Aqua v2. However, when I finally switched to the polycarbonate M-tank configuration, with the same e-liquid and open air flow, the overall quality of the vape greatly improved for me. It went from a muted and disappointing vape, to very flavorful and satisfying vape. I also have had no problems with chain vaping while using the M-tank.

I believe that the fitment, and tolerances of the lower SS tank section (inner space between the tank section and chimney bell) does have an effect on how the e-liquid feeds into the chamber and deck of the Kayfun V4. Due to the stiff juice control of my Kayfun V4 clone, I now prefer to leave the juice control at its open position, and simply refill the tank from the bottom with a syringe.

Collage 9


When Robbot Technology told me that they were doing a 1:1 replication of the new Kayfun V4, I was over the moon excited about it. Being that Robbot Technology had done so well with replicating the Zen ZNA body, I felt confident that they could nail the machining of this clone. So I am a little disappointed that I did not receive their best Kayfun V4 clone for this review. While 90% of this Kayfun V4 clone is very well machined, the very stiff tolerances of the juice control on my clone is clearly a defect. And unfortunately, the juice control is also an integral aspect of the new Kayfun V4 design.

To be fair to the Robbot Tech Kayfun V4 clone, I do know that this issue with the stiff juice control is not an across the board issue. I have heard very positive feedback for the Robbot Tech KF4 from other consumers, including some that have both the Robbot Tech clone as well as the authentic SvoeMesto Kayfun V4. But I can only review and judge the device that I actually received, and I was a little disappointed with it.

With regard to the new Kayfun V4 design itself, I have said since the first day that I built and used this atomizer that I felt it was an overly engineered design, and that it created too much work for the user. Can a great vape be had with the Kayfun V4? Yes, but you’re going to have to work for it. This is not a total slam of SvoeMesto’s new design because I understand the nature of creativity, and it is a constant process of recreating, and fine tuning to achieve an optimal result. I am willing to bet that SvoeMesto is already taking user feedback into consideration, and figuring how to best fine tune, and improve this newest design.

There are several different manufacturers producing Kayfun V4 clones, including Eycotech, Limwell, Shenzhen Easter, Tobeco, SXK, and Ivogo. I have already received the Tobeco made Kayfun V4 clone, which is presently getting very good marks on the ecig forums, and so I look forward to seeing if my lukewarm feelings about the Kayfun V4 clone will change at all.

Final photo


  • ​Well machined body and threads
  • check​Good aesthetic replication
  • check SS, glass and polycarbonate tank options


  • ​Overly engineered design
  • ​Inconvenient air flow adjustments
  • Exclamation Triangle Laborious tank configurations
  • Exclamation Triangle QC defect on the juice control

[box type=”shadow” align=”aligncenter” width=”600″ ]

Where to Buy a Kayfun V4 Clone


25 thoughts on “Kayfun V4 Clone Review”

  1. Paul (Nailz)

    I can’t believe how complicated they made this kayfun v4, people new to rebuilding, could pick up a kayfun and was a pretty easy to build and learn on, but this new one is going to be a challenge for even veteran vapers. I like to try a lot of the new tanks, but from hearing about all the parts and your review, I have no desire to try this kayfun, I get a headache just looking at the breakdown of it.

    Thank goodness there is reviewers like you to guide us ;)

    1. So true Paul .. The Kayfun has been the “first RBA” for many first time users however, I would not recommend this to a newbie. Kayfuns were known their simple effectiveness, this one will be known for its complications thanks to the overly engineered features. You are not missing anything here, although I do plan to give the Tobeco Kayfun a fair shake :)

    2. I got the Tobeco Kayfun v4 clone last night and set it up. I had a little trouble with a stuck juice control ring as well, but worked through it. This is my very first RBA and didn’t find it too daunting at all. Once you actually have it in front of you it makes a lot of sense how the pieces go together and didn’t seem overly complicated to me. Then again, I don’t have a previous RBA to compare it to.

      1. Well it is good that you were able to hit the ground running with this atomizer. Some people have a natural disposition towards making sense of things quickly, and some others not so much. The new Kayfun V4 is definitely a more complex design compared to all RBA’s that have come before it, including the prior versions of the Kayfun atomizer.

  2. I have 2 clones of the V4. One is the Tobecco which is in Black and working flawlessly the other I purchased with a vendor whom changed the manufacturer 3 times (Tobecco,EhPro, LeMaga) and what I ended up with is garbage. The e-juice flow is basically useless because of it’s manufacturing. It locks up to the point that I have to take the whole device apart to get it to turn. Their are other issues as well but I basically just wanted to say

    1) stay away from LeMaga V4
    2) The Tobecco V4 is done very well

    1. Thanks for that useful information, and I agree that the Tobeco Kayfun V4 is a fine clone. :)

  3. Another great review, but it would be better if the pictures comparing the e-liquid flow control in the open vs. closed position were taken from the same angle. With the change in angle, it is harder to see the difference in the two pics.

    1. Thanks for that note Bill, and I am inclined to agree. A faux pas that I noticed only after shooting. I will make it up to you with the Tobeco Kayfun V4 review which will post next Monday. :)

  4. Been meaning to comment for a while but never got to it. I also have the same version that was reviewed so obviously had the same problems as well. I thing i did figure out is the stiffness of the juice control can be adjusted by tightening or loosening the UC counter screw (no. 9 part, refer to diagram).

    That fixes one of the problems with the kayfun v4 clone. Now if anyone has got an idea to fix the resistance constantly fluxtuating I’m all ears.

    1. Thanks for that tip, I will remember to try this. I didn’t have any issues with my resistance fluctuating though, my resistance has been quite stable, so I can’t help out there. Perhaps your spring is too loose in the seat, or the tolerances are off around where the spring is seated?

      1. The resistance issue occurs on both the authentic and clone. I got a 1 ohm build and it’ll flux to as high as 2 ohms but mostly in the 1.2 – 1.4 range. I’m pretty sure it is a spring issue so i’ve been trying to find a site where i can buy all the silver plated items individually.

        As for the seating of the spring all I gotta do is drop it on the afc screw underneath the deck, no? Or is there a specific way to put the spring in place?

        1. I have heard about the resistance issues that some are having with the authentic and some of the clones, but I do not have this issue with either of my clones (Robbot Tech and Tobeco). On the Robbot Tech the spring is firm and tight, and does not come out when the UC connector is separated, it stays snug in place. The Tobeco spring does come out, but the resistance is still stable.

          A friend who has the authentic said that he stretched his spring out a bit which resolved his resistance fluctuation, so try that. Your spring is obviously not maintaining stable contact at the connection points. A .2 fluctuation is really not that big of a deal, but as much at 2 ohms is a problem. It might not be the spring at all, it could be the tolerances of the UC connector and JC that are off?

          1. Thanks a lot for your recent help. It does seem my prayers have been answered in the form of fasttech selling the individual parts. I’m hoping this will solve my problems or your stretching of the spring fix can do it. But what you said about the spring sitting snug in the UC connecter is interesting cause like I said mine hangs loosely.

            Really no atomizer is worth this much trouble for me but the V4 does produce some of the best flavour of all the RTAs currently available. So I press on…

          2. You are welcome hun, and I do wish you luck with it. Hopefully the spare parts from FT will help if stretching the spring doesn’t.

  5. I would really like to find this Kayfun affordable cause I think it’s reputation precedes it. This is the Rba to have.

  6. Hello everyone. I read a lot on Kayfun4 topics as i ordered one from gearbest and i want to be ready for it when it commes.
    I have came on two very interesting fixes for LC, but i would like to see some mre info on that.

    Solutin1: sand part no7 with sanding paper, but i didn’t find how fine (which granulation).
    Solution2: exchange teflon ring (part no.7) with rubber ring of the same size.

    I would like to get some feadback on this solutions.

    Sorry about my spelling, i am not form eanglis speaking countries. I tried my best ;)

  7. Good review. I’ve got the same version with the same problems (juice control tightness and fluctuating resistance). I played about with the spring tension to resolve the juice control issue (sort of) and stopped using a fixed pin mod to resolve the resistance issue (floating pins seem to work much better with this RBA.

    My biggest gripe with this RBA is the coil screws on the deck. They are a nightmare – small and not flat on the bottom. I have to perform major surgery to get the coil locked under those damned things. I tried swapping them out with other screws to no avail and eventually put it on the shelf to gather dust (it’s up there now mocking me!).

    I have the Infinite v4 clone and it performs flawlessly – but the machining on the RT v4 is superior to the Infinite. I can’t be bothered retapping the deck (I don’t really have the skill either truth be known) to put in proper coil screws so I might try to change the deck with some other v4.

    1. Hi there, and thank you for your comments. There is nothing worse then struggling to capture your leads while doing a build .. its almost criminal! Glad to hear that the Infinite KFV4 is working well for you, the Tobeco KF4 has been totally problem free for me.

  8. I have had the worst experiences with this clone. I had to bring it to my local vape shop just to get the chimney off! Terrible design with WAY too many parts, I will stick with my tried and true Kangertanks!!!!

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top