Not sure which forum to put this question.
I'm installing power duals on a 2014 UC Limited and would like to put some 18mm bungs on it just in case somewhere down the road I decide to use a tuner which uses 18mm bungs. I just don't know where to put them--near the heads or next to where the 12mm bungs are. What you think??

 

Thundermax wants them a couple of inches from the heads, not sure about the rest.

 

My understanding is that the bungs should be as close to the stock pipe distance as possible. So measure the distance from pipe flange to sensor on each pipe, and apply that to new pipes, and that should be optimal for sensor reading.
I have to do the same thing on my rear cylinder mgs true dual pipe as its not reading the pulse or exhaust correctly because its too far back on the pipe. Its about a foot farther back than the stock position.
On the rear pipe I believe its 19 inches from flange.
Hope that helps and makes sense.

 

The old 18mm sensors need different placement than the 12mm small O2 sensors. The new, small, sensors need the distance they have for two reasons... one is these are heated O2 sensors and if the MOCO placed them right next to the heads,... they would burn up... these are not made like the older 18mm sensors. The other is the ECU is programmed to 'wait' to read and knows that distance.

18mm sensors, OTOH, are NOT heated, so these rely upon being close to the exhaust port to heat em up. That is the "why" MOCO had them up there.

SInce you will NOT be using any 18mm sensors for the bike itself, you can have your wideband tuning sensors just about anywhere, as long as the distances are relatively equal.

When I tune a bike and it only has the 12mm sensors, I will use what is called Herko Blocks and drill holes in the pipes right about equal with the AC and install sniffer tubes and wideband sensors. The 12mm sensors on your bike are called narrow band sensors, in that they read a narrow value of oxygen richness. Narrow bands read each and every engine pulse and read the exhaust at a very high sampling rate... these need to be placed just right.

Wide bands do an average of the gasses passing by. So, they have a bit of room for you to have bungs welded in. They read way slower and since they are NOT part of the 'circuit' in use with the ECU... you have more freedom on placement.

Of most importance would be... the bungs do NOT face downwards, the sensor should always be a tick up from 90* to the ground. More 'up' is ok. Sensors should NOT be on the inside of a bend, outside of a bend is OK. The bungs should be straight bungs and the senor should be right into the exhaust stream, too. The older 08-09 bungs on a stock pipe are NOT really how you wish to do this, same area... near the heads or close, but outside of a bend and pointing horizontal or more up.

Has this helped?

Comparing stock locations with Wide Band placements is apples to oranges. WIde bands read way slower and average. Narrow Bands (stock sensors) read faster and for each and every pulse until it looses that ability around 5k rpm.

Put them near the heads, making SURE the pipe is on the bike and you use an actual 18mm sensor to ensure it all fits while the pipe is on the bike. The wires from the sensor should point upwards. The bungs should be short enough so that the whole heads of the sensor is in the exhaust stream.

Here is a rear clyinder with new bung. Yes... the weld sucks. HAHA! Also this is kind of close to the port for wide bands. But... see, what I mean about placement.

The fronts have very little room for proper placements and that pic will be next.



front bung





OK... I bought TIG welder and no more oxy welding. Make all the fun and get it out of your collective systems. HAHAH

On the rear bung, you can see where D&D placed the 18mm bung. This was just a so wrong placement its ridiculous.

 

I know that this is an Old post, But can these Bungs be gas welded? Mig Welded? Or must they be Tig welded?

 

Depends on how good of a gas welder you are, I do mine with a TIG only because I can do a better job this way.

 

I have a Tig and a Mig But I am just starting to play with them. I do better at gas welding but I am afraid to get the pipe that hot.

 

I suggest you learn how Wideband O2 sensors work

 

Well I suggest you learn how to read. The second paragraph spells it out for you

"SInce you will NOT be using any 18mm sensors for the bike itself, you can have your wideband tuning sensors just about anywhere, as long as the distances are relatively equal."

I've got to say that for your first post you bring up a very old post and then don't even bother to read it, isn't a very good way to start. wurk_truck also passed away a few years back so you will not be getting a response from him.

 

Wow, stumbled upon this forum and wanted to say thanks!!

I'm going to be tuning my 113" Evo via Wide Band and needed some tips.

Bike is a 1994 and I'll be running A CVV44 carburetor.

I can probably make it work via seat of pants method like ive always done in the past but i dont wanna waste my time dickin around with the time and efforts.

Curious to know why I'd need 2 bungs installed if its only got one carburetor?

Wouldn't the same readings be found if I were to check the other pipe?

Kenny Wise