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[blw]

Road Hog, I am in the same situation, I have a 09 SERG , thinking about removing the cat and putting in 1.75 Fullsacs. I am going to gain much and is it ok to do these two and not put in a SERT ?         Thanks everyone         BLW

[guppytrash]

Road Hog, I am in the same situation, I have a 09 SERG , thinking about removing the cat and putting in 1.75 Fullsacs. I am going to gain much and is it ok to do these two and not put in a SERT ?         Thanks everyone         BLW

I am no expert, just one of those guys who spends too much time reading mags and talking to guys who are experts. 
There will be many here who will tell you that you need an SERT.  If all you are doing is fulsac's and an air cleaner HD techs that I have talked to say you do not need one.   

[guppytrash]

Thanks, guppythrash, for the info.   

Here is what I am wrestling with concerning my 09 SEUC.  The bike has enough power for my two-up touring so that's no problem.   It does not need to be cutting edge fast; 100 mph is fast enough.   After owning an '02 RK 95" stage two that I finally sold because I could not afford to keep it running any longer and tired of being stranded in the middle of nowhere with a scooter that wouldn't run or run well, I want my bike to go 100K miles without rebuilds, get decent mileage/range and I want it reliable.  I understand the 110 has some issues.  For me it is about seeing things, riding technique and fast curves, not a bike project.  In a perfect world, I would buy just gas and tires, perform regular maintenance.  Lots of each.  I ride some 20K eash year.

What do you think I should address in this engine to reach my goals with this bike?  Popping the CC seems reasonable.  What else?

Road Hog

There are a number of riders here who have done the same mods ( cc drilled, fulsac 1 3/4, air cleaner & SERT).  The HP numbers seem to run around upper 80's lower 90's and torque 100 to 110.  I have not done any dyno runs yet. 
I have an Arlen Ness big sucker CC drilled, air cleaner, fulsac 1 3/4, and an SERT with the base map for performance air cleaner and performance exhaust.
 
You can see the dyno results from stock to these mods by looking at the thread  2" Fulsacs  on the SERG page.

All Thanks to this Jim Kerr and this website.

I am very happy with the results.  In hind site I would have done a dyno run with the Fulsacs and air cleaner no SERT to compare to dyno runs with the SERT.
As a heads up if you want more sound go with 2" Fulsacs.  I have the 1 3/4 and they are exactly what I wanted, but I would say they are barely louder than stock.  Much more of a performance sound with out the increase in volume.
The seat of the pants dyno says the exhaust and air cleaner mods were money well spent.
Good Luck

[blw]

One more question, is the heavy breather the one that turns forward in a cone or is there a different back plate to put on the one that comes stock on the SERG ?                Thanks,    BLW

[guppytrash]

One more question, is the heavy breather the one that turns forward in a cone or is there a different back plate to put on the one that comes stock on the SERG ?                Thanks,    BLW

Yes, I know Jim was asked that by someone else and that is the one he said he used. 
 

[blw]

Which one the forward facing one or the stock one ?

[ridefar]

This is agent Krantz of the Environmental Protection Agency, you are all under arrest! The fines will be devastating. The cost of good clean fun just went up!

[guppytrash]

Forward facing one with the 90 degree bend. 
If you go to the SERG page and read the post 2" Fulsacs it is all in there direct from Jim.
Take some time look over this site and you will learn the answers to every question you have.

[SBB]

I have a question.



I have read all 10 pages of this thread and can't find where it's addressed about how the flow works thru the pipe after the cat is removed.
I took a picture of my 2 into 1 into 2 header and marked it up with my concerns.
A few comments.

I measured from the outlet to the cat. and marked the pipe.
I measured from the other end (both) and marked where the cat starts.
The cat is 7" long.
I highlighted in yellow where the cat is being removed per this thread. There is clear clean flow there.
I highlighted in orange where there is cat remaining per this thread using the 1.6 core bit. There is restriction there.

My concern is this,
The rear header pipe has a clear unrestricted flow to the final "two" of the exhaust to exit as it pleases..
The front header has a very "bumpy" or "challenged" path to flow the exhaust to get to the final "two" of the exhaust to exit as it pleases.
The rear header flows well, the front doesn't. How can that be good for efficiency?

See my picture.
Don't laugh!
Anyone understand my concern?

 

[Twolanerider]

What you're describing makes it sound like the reverse of what's been happening for years previously.  Before the rear cylinder had such a difficult path to the left muffler that most of the exhaust esaped out the right side.  What you're describing makes it sound like a lot of the front cylinder's exhaust will now run out the left.

Without actually flow testing the pipes it's all WAG and eye-ball guesstimates anyway.  That being so do you think you're seeing so much restriction as to be a problem or enough restriction to be just good healthy back pressure?  Or somewhere in between?

[GregKhougaz]

The cat is 7" long.
I highlighted in yellow where the cat is being removed per this thread. There is clear clean flow there.
I highlighted in orange where there is cat remaining per this thread using the 1.6 core bit. There is restriction there.

My concern is this,
The rear header pipe has a clear unrestricted flow to the final "two" of the exhaust to exit as it pleases..
The front header has a very "bumpy" or "challenged" path to flow the exhaust to get to the final "two" of the exhaust to exit as it pleases.
The rear header flows well, the front doesn't. How can that be good for efficiency?

          No one is laughing as dead cats are very serious.      The cat I removed was 5" long.  You could be hitting a fitment or something when you measure from the engine side.  Looking into the pipe from the back after the removal seems pretty unobstructed and the flow certainly increased.  See Jim's picture and comment's in Reply #8, above.  That's what I saw when I did mine.  I don't know that you can differentiate between the two header pipes at this point.  You're right that the flow is not perfect but is sure seems to do the job.  

          What makes you say the rear header does not flow well?  BTW, could not see your orange highlight in the photo.  

[SBB]

What you're describing makes it sound like the reverse of what's been happening for years previously.  Before the rear cylinder had such a difficult path to the left muffler that most of the exhaust esaped out the right side.  What you're describing makes it sound like a lot of the front cylinder's exhaust will now run out the left.

Without actually flow testing the pipes it's all WAG and eye-ball guesstimates anyway.  That being so do you think you're seeing so much restriction as to be a problem or enough restriction to be just good healthy back pressure?  Or somewhere in between?

To answer the red question

IMO once the exhaust is past the opened up cat then it doesn't matter, it goes where it goes.
It's getting past the cat that I have an issue with.
The rear pipe has unimpeded flow.
The front pipe has a restricted flow.

To answer the blue question

Some back pressure is good, we all know that but my question is more about unrestricted flow.
The way I see it the rear has better/easier flow than the front.
But to throw another thought in to muddy the water.
If restriction gives us better back pressure then what about the 96" motors?
There is no cat there. Do they flow better?
We all have been told the 110 have the cats because of emissions.
So do the 96's have better flow and less back pressure?
Or do the 110's have better back pressure and less flow.


I think removing the cat is a great idea for performance but from my perspective it needs to be all of the cat, not just half.
Someone tell me if you think I'm wrong and why.

Anyone know where I can get a 09 96" header cheap?

 

[SBB]

         No one is laughing as dead cats are very serious.      The cat I removed was 5" long.Your right about yours but I went back and look at earlier post and Jim said his was about 7" long and per my measurements mine is also  You could be hitting a fitment or something when you measure from the engine side.  Looking into the pipe from the back after the removal seems pretty unobstructed and the flow certainly increased.  See Jim's picture and comment's in Reply #8,Look again at his post 8 the rear header pipe has an unimpeded flow path, then look at the bottom (front header) and you can only see a small portion of it. above.  That's what I saw when I did mine.  I don't know that you can differentiate between the two header pipes at this point.Look at post 8 again,  You're right that the flow is not perfect but is sure seems to do the job. No offense Greg but getting the job done is not what I'm looking for, I want it to flow all it can.  

          What makes you say the rear if I said rear, I meant front.header does not flow well?  BTW, could not see your orange the orange is like a dark dark yellow, it's the section on the bottom of the pipe.highlight in the photo.  

[SBB]

I must be on to something.

No one has said I didn't have a valid concern about drilling out only half the cat.

Hmmmmmmmmmmmmmmmm.

             

[hdbrad03]

I did not core mine out. I used a 3/8" 12" long carbide drill on an drill extension. It was a alot more work but I was able to remove alot more of the cat. During these cold winter night that are coming I may try to remove additional remains. I only have a little bit remaining on the bottom. I have added 1 3/4" Fullsac baffles and for the price the performance has improved greatly. I can still hear the radio. Best dollars I have ever spent on an exhaust upgrade.

 
     Brad