This is for you Brothers that like the look of the low profile stock exhaust on the Tourers, that still want the "Venturi Effect" of the collector cross over that helps to exhaust out the Cleaning Cycle of the cylinder with the exhaust of the firing cylinder in the 4-Stoke.  V&H Power duals for instance, have acknowledged that the the Powerduals have a 4 HP advantage over the "Dresser Duals" that more look like the stock exhaust but do not have the cross over collector...  Anyway, we now have real time Engineering testing.

This was on a 103, stock exhaust with Monster Ovals, on a Street Glide.  It was tested on the in shop Dyno, before and after Cats, and the Dyno results were significantly surprising...  It was a neat 10 HP difference.  You would factor that down for a 96 or an 88, but the Dyno results were graphed and printed out on the exact same Bike, and surprised everyone...

Method of cut and shut was far simpler than I had originally thought out.  On the "Collector" before the cross over tube turn off, you cut out the inside panel, the inside of the collector area, with a small cut-off wheel on a small grinder with a thin metal cutting wheel..  It is a clean cut, that is easy peasy to TIG back neatly without distortion...

 

Hope this helps some of you, cheap for 10 Horsepower,

Cowboy, Old School HD Tinkerer

Hey Cowboy,

OK-- let me get this right as it's a job I need to do and I have the welding skills to do it. SO-- you didn't cut the collector in two pieces; rather you cut a window into the collector and gouged out the cat shit then welded the window back in?

If that's correct could you nominate what the dimensions of the window should be, and the measurement from the cross over turn to the start of the window? What did you use to gouge out the cat shit? Anything else I should know?

Thanks for your time in reply.

Hiya V2,

Make sure yours is the same shape, this is off a 103 Street Glide.  It starts at the casting right behind the collector per this picture, which is the same as on my last Ultra as well.. As to the welding skills, TIG would be nice as it is stainless.....

I can't give you the dimensions, as I have not had the chance to do it myself yet.  I had the idea, and was talking with a local Shop about the "Cut and Shut" to do on my own new scooter coming next month, and they took it further themselves and forwarded back these pictures.  But I had this same Header on my last Tourer, an Ultra, and it was identical.  From memory, now don't go on this for sure, but from memory it was the same on my Road King with the 96 c.i. as well.  I thought it might come in handy to some of you, especially since they Dynoed it before and after...

Good luck with it.

Good one Cowboy!-- Big thanks for the pic. I can see they cut just in front of the weld and (it looks like) they went deeper on the bracket side. Without seeing the pic I wouldn't have made the cut so deep on that side. TIG is the best way to go for that work.Yep-- I can do that. You've made my day-- Cheers.

Cowboy, I'm at home now and can see all the pics-- I looked your original post at work and I couldn't see the first set of pics as I'm blocked out, but I could see the additional pic you sent as my email tracking is on. Makes the rest of my posts look/read "stupid" LoL.
Was reading elsewhere that the cut can be 5" long by 2.5-3" wide and is enough to get the catalyst out. Also if done from the outside of the collector the heat shield totally hides the weld-- could be a good thing to do as well.

In the pic of the catalyst it looks like they dug into it from one side and rolled it out of the slot-- could be why the cutout is big.

10 HP on the Dyno for a 103 c.i. is HUGE...  I have an Ultra on the water, and will pick it up with this already done, already priced in.   Even if they ever inspect for stock header pipes, (doubt it in Qld),  they would have no way telling if the cat was there or not...  I like the clean lines of the stock headers.  My new Ultra is coming with a 110 c.i. so it could be 11 or 12 HP increase on that with the Fat Cat Monster Ovals underneath... 

Glad to be of help, enjoy, Ride Free, Ride Safe.............  Cowboy

Hi Ya Street Bob.....  Don't know how you did those links, I am having trouble just trying to load more than one picture... heh he...

Now back to HD Engineering...  I am a Tinkerer, and like to know how things run so they can always run better.  In the Old Days, you HAD to be one to keep your Scooter on the road.  My first shovel was a 1966, first year of Shovel, jammed into a 1957 straight leg rigid frame, downlegs stretched two inches so a 10" over Wide Glide sat level, Jockey Shifter, Suicide Clutch.  You HAD to be a fairly good Mechanic to keep thoses on the road, and those that were not handy were the ones that had to be picked up by trucks.... heh he..  Gave HD a bad name, when most of the time it was a non-mechanical Rider.

Anyway, my point:  Street Bob, be careful with the American exhaust mods tips.  I have learned on their Forums that our header system is only for export like here and Europe.  They do not even have that stupid flapper valve we have to block open to get the true dual exhaust when cold.  I am not sure the cats or collector are the same either, and that is why I posted these pictures.  While I have not seen one, I have heard some of theirs have two cats, a smaller one for the right and another in the cross over.  Ours is one big cat in the collecter, and the one he shows on the U-Tube looks radically smaller...

After the removal, the sound is louder, but also less muffled and more of a Thumper we all like, a sharper exhaust sound.  On these twin cams, I have always gotten rid of the stock headers, this is just my latest engineering idea to keep the clean lines of the stock exhaust on an Ultra.  Also, the V&H collecter on my Street Glide, and when I had it an Ultra, and on a 96 c.i. Road King, all of them would drag once in a while... 

If I kept this latest PowerDual on this Street Glide, I would grind clear through eventually...  It is slung too low, a disadvantage for it.. It is not only that I like the lines of the stock headers on the new Ultra, the V&H is also really toooo low for a Street Glide.  Here is a picture and you can see whay I mean, I think it is 40-50 mm BELOW the frame...  It is not just that I like the clean lines: Stock Header, cat out, is going to be just about as good on performance, cheaper, and better clearances..  Ride hard, Ride free, but stay safe...   Cowboy, trainer of Horses and Harleys...

Two Tone and Street Bob,

One last bit of help possibly:  After bugging them a couple of times by email, V&H finally told me the True Duals was a 4 HP loss for not having the crossover.   Now that is not a lot, but what it comes down to is the exhaust from the firing cylinder helps to extract the exhaust from the cleaning cylinder in the 4 stroke system.  This works by the "venturi" effect, where the exhaust stroke blasting alongside the cleaning stroke in the cross-over, creates a vacuum on the cleaning cylinder actually helping it make that clean out stroke... Hey, 4 Horse Power is 4 HP...

That is why I have not just ordered the V&H True Duals, for about the same clean lines, is because they have no cross over and you actually are losing HP by not having it.  That is why, not just money, that is why my engineering study on removing the cat from the stock system, as both pipes enter the collector in the same place so you will get that vacuum "venturi" effect and not only save money but pick up Horse Power...  

Why not keep the cash, get the same clean lines, and possibly gain some HP.  I am not saying it is definitely the way to go but: Just a thought if you have not committed your $$$ yet.  My idea has also now been taken up by a local HD shop and the Owner has done it to his for the same reasons...

Cowboy, training Horses and Harleys... heh he..

V2evo96, and Street Bob, and any others that might want to do this....

Here is the latest engineering on my new Bike, same cut, BUT REVERSED ON THE OUTSIDE..   Kitty kicked out...  This way you cannot see the cut or weld up of the window, the outer heat sheild covers it...  Here is the picture of it done on mine, this is a first and everyone thinks the best so far.  The exhaust is not as muffled, a little clearer, and with the Monster Ovals on my new CVO Ultra, it is LOUD... But not too loud to be irritating, just a bit loud around town for "no blind spots.. heh he  Major improvement, still the extractor two into one cross over for exhausting the cleaning stroke cylinder...  And CHEAP to do...    Hope this latest idea is a help... In the picture you are looking down at it from the top and can see nothing... nuttin but cool...

 

Freak performance, smooth running, with this Cat Gut stock Header design and V&H Monster Ovals, it is either a FREAK engine or this is a Magic exhaust trick. I really cannot account for it any other way but this exhaust trick as the fuel economy is the best I have seen....  My new CVO Ultra is getting better fuel economy than even the O/B Street Glide above with the same engine.  The Blue CVO Ultra just went 1600 kms in the past few days, and I AM STUNNED....  This engine is the smoothest twin cam I have EVER ridden.   It acts like it came accidentally balanced from the Factory.  All I can put it off to is this exhaust.  The same power as my CVO but my fuel economy is about the best I have ever gotten out of any Twin Cam, and I am getting about 430 to 440 kms per tank, about 19.5 kms per litre, almost 20 kms per litre on the highway, at about 100 average at 2500 RPM.  And I am heavier, and not even well run in yet.

With road works, 80-100 in NSW, probably 90 kph average, and 110 av in Qld, it averaged about 100 kph over the 1300 kms or so since we left on Friday, with a few hundred run in before we left I am sitting on 1600 kms since I picked it up on Wed.  Seven Brothers met up on an interstate run, and it was: Smooth, smooth, smooth.  It is going in for the first Service on Thursday... This is the best fuel economy, and it is not running lean, cool and smooth, the best of any Twin Cam I have owned.  Better than my 96 or the 103, and even better than my 2011 CVO Street Glide with the same engine.  All that is different is this exhaust so I either have a freak engine, or this exhaust system is a nice combo.  Being a fair engineer, I am guessing the later.  The mix is right, not running lean... This exhaust combo suits the engine, and I like the look filling in under the bags with the Monster Ovals.  It is a bit loud around town, but a great low tone with everyone liking the sound of it.  Magic fuel economy.... I hope this helps some of you...

BTW, my 2011 Orange and Black CVO Street Glide shown above is for sale on bikesales.com.au   This Ultra is so good at my age I don't think I will be riding the FLHX any more... 

Count your blessings Cowboy-- sounds like you got a rare smooth one ex factory. Have you had a tune put on it?
I'll be gutting my cat in a few weeks from the outside as you did. When I make the cut I intend to cut the 4 sides on a slight angle to bevel the header section towards the I.D. That is, after the gut I will have a coupon plate that will just sit on the hole and not want to fall in while I tack it in place.

I've had the BargeGlide on the lift for 2 weekends while I bolted on some cosmetic changes and installed the SE compensator. Been waiting for a SE clutch diaphragm spring which just came in so just need to install that and button the primary side up. Will ride into September when the warranty runs out then gut the cat and install cams.

Hello V2evo96,

This is an answer to your question, but I hope it helps others with the later model Twin Cams.  It ended up being a savings on headers, no need for a Tuner, and the best fuel economy I have seen.  My engineering experiment has had some amazing results.  First of all, I like the looks of the Modded stock headers.  But the combo of that Cat Gut mod, has had a far more impressive gain than just the look I like of the clean lines of the stock headers.   In answer to your question, appears that I also do not need a Tuner or a Tune. i will confirm after this first Service with fuel air mix test again.  The "Venturi" effect, of aiding the cleaning cylinder with the exhausting one, has given me the best fuel economy of any twin cam I have ever had.  Better than my 96 Road King, 103 last Ultra,  110 SE Street Glide even though it is lighter and has the V&H Power Duals.  I am getting about 430 kms per tank average for 22.8 litres..  The truth is on the last fill on the highway run before I was back running around town, I had gone 300 kms and still had 150 showing on the reserve setting and that has proven pretty accurate on mine.  That is an impressive 450 per tank and not even fully run in yet at only 1700 kms right now, almost 20 km/litre.

This means that my Cat Gut stock header combination with the V&H Monster Ovals, is a magic combination that suits this engine (I am not that smart, just lucky with this experiment)....   I am in for a first Service tomorrow, and will have them check the exhaust for the right fuel air mix, but in the Twin Cams if it were running too lean you get the pop and crackle on deceleration and I get very little of that.  It is about right without a Race Tuner, and without a Tune, so my invention of the Stock Header mod not only saves you money on the aftermarket headers.   This still has the Venturi Effect helping the engine with a 10 HP increase, so it looks like you not only save money on the headers, and saves you money on a Tuner,  but also on fuel economy.   I hope this helps some of you, as this looks to be about a $2000 savings that keeps on paying off.  

And I like the look of the stock headers clean lines>

 

Hello Brothers,

Now over 3000 kms this month, and fuel air mix is fine.  Still do not have a tuner, first service cleared that one.  Several othe bikes have been done in the local area now and this all seems to be working well.  It looks like Cat Gut and low restriction mufflers gets about 8 HP on average, at least that is reported.   It made it breathe, run cool, and increased fuel economy.

My guess it is a full success..  There is a sizable savings on pipes, and no tuner necessary, but the main thing is I like the look and routing of the stock pipes on the Tourers...  Hope this has been a help to some of you..

Best regards, Cowboy

NO Tuner?
It surprises me no tune was required after modifications. Lots of $$ to be saved if this is the case.
Did you have any changes to tuning other than pipes and removing the CAT or did you get a one off download (MAP) to compensate for pipe and CAT mods?

Hello Wild Child,

A little slow in getting back to you...  The 110 CVO SE engine in my Ultra did not need a re map.  Analysis showed the Fuel Air mix good all throught the range.  So yes a big savings on $$$ not only on the pipes themselves, but also for the Tuner and VCM (Com Module) that was not needed.  I put this off to the matched engineering of HD themselves, where the same engine with my CVO Street Glide (now sold) with the Power Duals, needed the Tuner and VCM com unit.

I had actually forgotten that until I packed up the Street Glide for Delivery and found the Com Unit module...  Anyway, no, nothing required so I would further recommend this whole proceedure.  The Monster Ovals from V&H also have a gread sound to them..  A little loud for a some, but perfect for my tastes.. 

Cowboy

Well Bros,

8 weeks on now since Delivery Day, 4500 kms, and the fuel economy looks to be nearly 450 km per tank now..  I went 420 kms with the H.O.G. on Sunday last, before, anyway I had gone about 420 kms on the day and still had fuel left when I hit the Servo...

It is more like 370-380 to 400 around town because I am a die hard HOON...  But on the straight hiway runs it seems to be getting even better.  Before I had to keep the speed down to get the good economy.  But now as it breaks in better, I am getting the best mileage even at Hoggie Hoon speeds of what I will not mention but waaay over the top on the way home...  Heh he..

From an engineering perspective, it may be because of the HD Engineering on the size of the pipes... Now I say that because me Street Glide with the same engine (now sold) it did not get as good of fuel economy and it was lighter.  This could be from a slightly different ratio somewhere, or there is talk that a slight bit of back pressure is needed to get the right combination.  My Streetie needed a tuner, and this CVO does not and gets better fuel economy with the Cat Gut Factory Pipes (CGFP) than the Streety did with V&H..

Hope this is a help to some of you, as it was a savings of well over $1500 with no V&H and no Tuner needed.... Bye for now.. Cowboy on the road.  8 weeks and 4500 kms, about as much as I have ever done...

Well DodgyDave,

First of all you might want to understand that the big Tourers have a 22.7 litre tank, and  Secondly, as a matter of fact the report is actually quite correct...  Fair Dinkum and right on... Serval times I have gone over the 400 km mark and still showing reserves indicating about a 450 km range to empty, on this 110 cu.in.  S.E. engine, (but only on the highway.).

It just happend on this last trip with the Hoggies, I was on 420 kms on the clock, dead accurate, and still had reserves when I filled up.  So YES frigging way it is.!  

The purpose of this whole thread is to save some Brothers about $1500 to $2000 dollars in headers and tuners, with this mod  cuz it works so well.   Cowboy... 

FYO,  You are right, I have shared this on the American CVO Forum and there are others getting high mileage reports, some comparing notes by P Messaging...

Maybe I just have a freak combination, but I have run out the tank to 420 kms and still had reserves making me calculate I could go the fabled 450 if run to dry...  Now maybe I have a freak engine, and my engine is happy and smooth in 6th at 100 where most downshift..  Maybe it is a freak, but on the LEAN LEAN: This is my fourth twin cam..  If they are running lean with a free exhaust and no tuner, you get a lot of snap crackle and pop on decompression as you coast down.  I have a very little, but none of the extremes I would have if running too lean...  Also, looking back, my 103 ci got better than my 96... ???  And now my 110 cu.in, gets better than my 103 did.  Maybe I am running on the higher torque, down lower in the gearing to account for some..

Maybe I just have a freak engine combination on this particular CVO Ultra...  Or, maybe again it is this pipe combo that offers just the right engineering.  Mind you, I only get in the 380 range around town and country combo... This 420-450 thing is on long highway runs..  I did it first coming up from NSW on a 650 km run, and again on a 420 km run a couple weeks ago.  Top Octane I can find, and refuel was at about the 420 mark on two occassions when I was still not dry.  Just saying, that is the way it is...

Regards, hope a help, Cowboy

 

 I can't vouch for anything else in the thread but I made Ceduna to Port Augusta on a tank with a lot of praying at the end. Its 465km.

I incorrectly thought I could fuel up at iron knob.

But this was all cruise control at very close to the speed limit and I don't want to try it again.

Plenty of 400ish while  touring tho.

cheers

Surly

Hey Surly, You hold the record... 

 Here is the current report on the Cat Gut 110 ci..  I went 406 kms last week with the HOG and still had reserves but much less than before... 120-130 kph at times for the last 200 or so kms knocked the mileage on the head.    From my experimenting, it seems like the lower the speed towards the speed limit, the better the mileage.  Also, now it could be my imagination, but early morning fuel up and you seemed to get a little better mileage as well, like as if the fuel heated up over the engine and expanded. 

I am guessing the combo of them both adds up to about 10%, where the normal 400km out of a tank, makes the 440 well acheivable at morning fuel up and running speed limit.  My reserve read out has called for the 450..  But you hold the record actually running near to dry.   I have hit the 420 a couple of times with some reserve left like over a litre, which would be that 440 450 range to empty or a little better..

Unlike my 96 and my 103, Motor is so smooth and happy  I am able to run in 6th at 100 kph, running on torque of the 110 c.i..  Now 6000 + kms in the 11-12 weeks since new.  Some small chance of crossing the Nullabor next month on a rally, that will put it to the test for sure.  Clean Cat Gut, Monster Ovals, breaking in now, if I keep the speed down I am sure of the 450 / tank.  Around town, maybe 360-380... 

Keep Riding Free in the Wind... Only a Biker knows why a dog stickes his head out the window...