Airflow/Draw Issues with My Russian 91 Clone

[catmomma]

I recently received a Tobeco Russian 91 Clone. I took it apart, cleaned it thoroughly and decided just to try it with one of the pre-built coils it came with while I waited for an order of Kanthal. My problem is that with the tank on, I have barely any airflow at all. I even compeletely removed the airflow screw which helped a tiny bit but the draw is so tight, it's unvapable. If I give it a draw from the chimney without the tank. it's fine, but as soon as I put the tank on, then nothing. I poked a small needle into the airflow hole, in case there was gunk or shavings in there an again, nothing. I am new to this type of RBA so I'm wondering if I'm doing something wrong. Is it just a matter of drilling the airhole a bit larger, or is there something else I should do? I have read that the draw on the KFLs and the Russians is tight but seriously, this is impossible to use this way. I'd appreciate any input.

 

[folkphys]

Obstruction inside yer drip tip?

 

[catmomma]

Obstruction inside yer drip tip?

Nope, tried a couple of different tips too, just in case.

 

[State O' Flux]

If I give it a draw from the chimney without the tank. it's fine, but as soon as I put the tank on, then nothing.

If you've already tried big bore drip tips, then the only remaining obstruction, when compared to your above description, would be the top cap hole diameter... which makes no sense, because it's larger than the chimney top cap ID.

Drilling can be a waste of time. The smallest diameter orifice in any air flow system is the determining factor for net air flow... so enlarging the diameter of only one element, say the base for example, does nothing for you... if, for example, the positive block retention screw/air tube ID is still smaller than the orifice you've drilled out.

 

[Portertown]

Did you remove the bottom 510 positive screw and positive coil mounting block? Sure sounds like there is an obstruction in the hollow positive screw to me. This is the pathway for your air. When you draw through the top of the chimney(without tank) you can suck air in through the juice channels, but with the tank together you can't. When this screw is out, fully check all the passages that air travels through.
Sometimes there is metal chips from the machining, cutting oil or plastic shavings from the bottom insulator in the air channel in the hollow screw.

 

[ericbnc]

I recently received a Tobeco Russian 91 Clone. I took it apart, cleaned it thoroughly and decided just to try it with one of the pre-built coils it came with while I waited for an order of Kanthal. My problem is that with the tank on, I have barely any airflow at all. I even compeletely removed the airflow screw which helped a tiny bit but the draw is so tight, it's unvapable. If I give it a draw from the chimney without the tank. it's fine, but as soon as I put the tank on, then nothing. I poked a small needle into the airflow hole, in case there was gunk or shavings in there an again, nothing. I am new to this type of RBA so I'm wondering if I'm doing something wrong. Is it just a matter of drilling the airhole a bit larger, or is there something else I should do? I have read that the draw on the KFLs and the Russians is tight but seriously, this is impossible to use this way. I'd appreciate any input.

How far in does the needle go - just a little bit or in almost half way through the base?

I had this problem with a KFL+ clone too. I took a diamond needle grinder set (Harbor Freight)and went to work on the air hole. after a couple minutes of hand turning the bit sank into the hole - looks like the air hole wasn't completely open. I hit it with some compressed air and a small metal disc the size of the air hole fell out. I worked the hole for a while longer to smooth out any leftover machining and now it hits like a champ.

 

[catmomma]

How far in does the needle go - just a little bit or in almost half way through the base?

I had this problem with a KFL+ clone too. I took a diamond needle grinder set (Harbor Freight)and went to work on the air hole. after a couple minutes of hand turning the bit sank into the hole - looks like the air hole wasn't completely open. I hit it with some compressed air and a small metal disc the size of the air hole fell out. I worked the hole for a while longer to smooth out any leftover machining and now it hits like a champ.

It goes in most of the way, but not all the way through. I will look at this more closely and see if the blockage is there.

Did you remove the bottom 510 positive screw and positive coil mounting block? Sure sounds like there is an obstruction in the hollow positive screw to me. This is the pathway for your air. When you draw through the top of the chimney(without tank) you can suck air in through the juice channels, but with the tank together you can't. When this screw is out, fully check all the passages that air travels through.
Sometimes there is metal chips from the machining, cutting oil or plastic shavings from the bottom insulator in the air channel in the hollow screw.

Yes, I did. Center airflow hole is fine, I didn't however check the the block itself or the hollow screw. Will check this too.

Thank you both for your suggestions!

 

[mjohnsoniii]

Any luck? Did you get it to start hitting? I'm wondering because I have the same EXACT problem.

 

[Asmo6]

Devoid of patience, I simply went directly at the air hole with a drill bit. It is still a bit more stifled than my 3.1. But it is passable now. I found a bit that fit, grabbed the next size up to chamfer and kill the whistle... Then decided to just run that the whole way in. And grab a size up again to chamfer and solve the whistle.

It's better, but not ideal.


So, yes, there is probably an internal choke point. But opening the air hole did seem to help some. Maybe I'll pull it all apart some time and try to find it.

 

[mjohnsoniii]

I tried drilling out the air flow hole but the tip of the drill bit broke off inside and no matter what I try, I can't get it out. Dagnabbit!

Sent from my SGH-I317M using Tapatalk

 

[SkvLTD]

Holy crap, how hard were you drilling? I drilled mine out a bit, mostly to get rid of the whistle due to outermost hole being some odd size and it's been real good to me since.