Not your typical Mikuni 38 mod

[Polish jet pilot]

Hi All,

I bought a ste of atomizers off ebay (NOS). I think made by PROK. I want to bore my carbs to remove all obstructions. I was thinking to bore the venturi carb and press the atomiozers in. They are brass with rubber oring and 6-8 holes. The outcome should be a mist of fuel down the carb... what you think?? Thank you

We had a discussion on these before, I was thinking that maybe some builders would chime in about these...

 

[Big Kahuna]

if you want to loose performance then go ahead and remove all the obstructions. JSS did this and many people had issues. Those ramps are there for a reason.

 

[Mouthfulloflake]

I have a carb that is set up like that, it is a large improvement over stock.

I think its a Keith Head, or someone modded carb, a single 44, bored to 53mm, and nothing in the throat, holes all around inside.

works very well.

sort of pics.

http://www.x-h2o.com/threads/37497&highlight=annular

 

[Foximus]

I wanna see a pic. I couldnt find any on ebay....?

 

[Dustin Mustangs]

The blackjack mod removes all those obstructions, even the bomb site:

http://www.jetworks.net/blackjack2.htm

 

[SUPERJET-113]

I started a thread a couple months ago when I first saw them on Ebay. Good discussion about them.

Follow the first link in the first post of this thread to see a old Ebay auction of them:
http://www.x-h2o.com/threads/65112&highlight=atomizer

 

[SUPERJET-113]

Or here is the old Ebay auction link:
http://cgi.ebay.com/ebaymotors/Atom...rcycles_Parts_Accessories?hash=item2ea86de910

 

[Mouthfulloflake]

Oh ok, thats different than the old modded carb I have.

 

[Big Kahuna]

I have a carb that is set up like that, it is a large improvement over stock.

I think its a Keith Head, or someone modded carb, a single 44, bored to 53mm, and nothing in the throat, holes all around inside.

works very well.

sort of pics.

http://www.x-h2o.com/threads/37497&highlight=annular

Modding a 44 is totally different than the 38's.

 

[#ZERO]

Here's the PROK atomizer thread; http://www.x-h2o.com/threads/65112

If you taper bore the carb leave the outer venturi wall alone because you'll drastically reduce the main circuit signal and it will make the carb harder to tune.

I purchased a few of those atomizers myself and have yet to try them out. I was going to use them on a set of 38's first since they're a dime a dozen.

 

[Breese08SJ]

Just seems to me that the average person does not have the tooling IE Mill and porting tools to perform this work in a precision nor timely fashion... Figure in the cost of the carb/s even if they are dime a dozen 38's plus the tooling and time / labor, is it really worth the effort?. It also seems that no one has stepped forward to say they have done this mod and had success, One would think that if the performance gain and ease of mod were worth it everyone would be doing it. Getting this type of mod done by say... Art @ JetWorks does not cost that much and you are guaranteed a carb that performs, not some hacked up OEM carb hacked up in someone's shed that prob will not perform and just cause more headaches than it is worth when it comes time to tune.

 

[Big Kahuna]

These atomizers when they were produced use to come with a drill guide so you could do them at home.

 

[Breese08SJ]

This is true BK my point was more that if these things worked Professional Engine builders like Art and Chuck would be using them.... I dont think these inserts themselves will provide a huge gain. Maybe just maybe if setup right along with boring the throats etc they might the combo has to be just right. Fuel Atomization and air flow are not something the human eye can see. The understanding of high / low pressure areas, directional flow, and inlet tract speed around the bombsight play a major role in carb performance. Who knows maybe with a little work and these inserts a super carb will be born. Yea I doubt it....

 

[2XLR8]

They were not sold for very long. I think what you buy is overrun and product that would not sell. An over estimate of potential sales. If this was not true we would not be asking all these questions 10 years later. If they worked every body would know about it by now and Im sure there were probably be more than one guy making them by now.
To claim better performance on an otherwise stock and unmodified carb you would have to do 2 things. improve the air flow which it does not or fix an inherited fuel supply inefficiency. This would mean that engineers at Mikuni didn't do their homework. I doubt it, but then again I doubt a lot of things.

 

[Mouthfulloflake]

Modding a 44 is totally different than the 38's.

How so in this regard?

 

[Dustin Mustangs]

To claim better performance on an otherwise stock and unmodified carb you would have to do 2 things. improve the air flow which it does not or fix an inherited fuel supply inefficiency.

What about improving fuel atomization? I imagine that was at least the hope with these.

 

[Big Kahuna]

How so in this regard?

The inside of the throat body is different, the 38's are designed with all the different protrusions. I am not an engineer but they all help with the air flow, atomization and signal.

When JSS started grinding all of these out, they seemed to only work well in motors with the Dry Pipes and Porting. You throw in a B Pipe and many had issues and could not get them tuned in. Parrdaddy, Freestylegeek, SJ13 (Abe, Northgraphics), I think Darin may have tried a set. and a few others (cannot remember names at this point) None of these guys would ever get the carbs to run right. I even offered to install a set for John while I was up there at Lanier once and see if we could figured out what it was about the BPipes that made these carbs not work right. He gave ever excuse under the sun why he could not.

Protec as far as I know does not go down and grind all of this out, all they do is taper bore out the top of the carbs for increased airflow. I have never heard of a set of their carbs that did not work as advertised.

The 44's do not have these same protusions. You can taperbore them from the top. You can step bore them from the bottom (TLR Mod that he designed for Rick Roy that worked really well in single applications, opened the bottom below the butterfly to 48mm).

 

[Mouthfulloflake]

Thanks for the explanation BK, I guess its been too long since I messed with both in hand, Ill have to look in the garage, I was thinking they were very similar inside.

The inside of the throat body is different, the 38's are designed with all the different protrusions. I am not an engineer but they all help with the air flow, atomization and signal.

When JSS started grinding all of these out, they seemed to only work well in motors with the Dry Pipes and Porting. You throw in a B Pipe and many had issues and could not get them tuned in. Parrdaddy, Freestylegeek, SJ13 (Abe, Northgraphics), I think Darin may have tried a set. and a few others (cannot remember names at this point) None of these guys would ever get the carbs to run right. I even offered to install a set for John while I was up there at Lanier once and see if we could figured out what it was about the BPipes that made these carbs not work right. He gave ever excuse under the sun why he could not.

Protec as far as I know does not go down and grind all of this out, all they do is taper bore out the top of the carbs for increased airflow. I have never heard of a set of their carbs that did not work as advertised.

The 44's do not have these same protusions. You can taperbore them from the top. You can step bore them from the bottom (TLR Mod that he designed for Rick Roy that worked really well in single applications, opened the bottom below the butterfly to 48mm).

 

[Big Kahuna]

plus the inside diameter is about 6mm narrower.

 

[vomitspot]

These atomizers when they were produced use to come with a drill guide so you could do them at home.

i have that drill guide in my tool box