New Project: Exhaust Headers

[TopCatGr58]

Hey Folks,

Okay, now that my front brake Special mod is done and functioning, I'm turning my attention to the next project that may hopefully provide more benefit to members in need of replacing worn/rusted out headers at a reasonable cost.

First the design. I don't have any fancy mandrel bending capability! I've already acquired a modest amount of pipe sections....straight and mandrel bent. I have 90 degree bends that can be cut at 45 as well. I've researched the places to acquire the pipe sections, and they want astronomical prices for the "Y" sections....like $45.00 or more EACH! So... the first problem is the junction of the 2-1 pipes for each side. Most folks use or want a 4-2 system, so that's what I'm going to try first!

The OEM design of the headers have the inner section being both flattened so that it's a wider area and at a 45 degree type curve as it joins with the straight section of the outer pipe. My prebent sections are just ROUND, I don't know how well I could FLATTEN that section prior to attaching/welding it to the other pipe into its SIDE, as well as cutting out the matching OVAL shape, and also have enough room to be able to get the TIG tip inbetween the 2 sections!?

See the simple diagram below. First shows the OEM shape. Second shows just joining the pipe using a 90 degree bend.....as variation of this could be done with any angle...the header pipes don't have to be parallel....they could be angled at a slight converging angle to the junction joint, so that the bend can be cut at any angle between 90 and 45. The 3 is cutting and using 2 bends, each 45 degrees of curve, cutting a parallel cut so that both ends could be welded up, and then a hole cut in the joined end to afix the round pipe section that goes to the muffler. This last idea would provide the same bend and theorhetically the same resistance vs. 1 straight thru and 1 having to go around a 90/45 degree bend!?



Okay, thoughts, ideas, etc.?!

T.C.

[crazy steve]

You need to pick up one of these.... http://www.harborfreight.com/pipe-tu...her-42324.html

The other thing you need to decide is what size is the outlet pipe to the muffler going to be? The stock head pipe is only 1.5" OD (actually, the ID is a bit under 1 3/8", so that size would be a closer match) but nearly all aftermarket mufflers are 1.75", although larger sizes can be found too.

Getting the 'wrap' under the lower frame tube will be the trick...

[Joab]

Oh, I love these threads. Its like watching evil geniuses discuss their next plot for world domination!

Gives me tingles!

[TopCatGr58]

Stimulating the brain cells again.

Hey Steve and others,

Okay, here's another approach, see new diagram below. Again having the header pipes come down from the engine at a slight angle to each other,
and then flattening out the inside edge of each pipe a bit, welding up the joining seam, and then fitting the 1.75" diam pipe over the junction and welding up around it to make the seal.



A lot less fancy cutting and molding, will have to make a jig to fit the headers onto for hammering flat and also mounting them to temporarily while welding up the seams so that they will fit into the head when done. So...may not need that fancy notching drill afterall!?

It's raining cats and dogs today, still haven't gotten my 220V line put in the garage so don't have the full power of my plasma cutter available....YET!
Just hoping that the end result doesn't look to much like Frankenstein's Monster with all of the seams and such between the elbows and straight sections!

T.C.

[Rasputin]

JAT but it may be easier to copy a 4 into 1 or even the spaghetti type header. I fully realize what you want to happen but a type of exhaust that works, is better than trying to copy one that requires crossover tubes etc. It may also be easier to replicate than the stock exhaust. That said once you have a working exhaust sytem, then you can move on to trying to replicate the original type exhaust pipes. Just thinking out loud here!

[TopCatGr58]

Hey Rasputin,

Yep, this is what I am doing, thinking out loud, running ideas by and seeing what looks feasible. Just curious, how would you characterize a "working" exhaust? I'm not necessarily trying to copy the OEM design, just trying to find a way to make a basic 4-2 type of header set, simple 1-2 and 3-4 paired together like the OEM and the Mac's, not wanting to add the complexity of a crossover pipe. I know I've heard from several folks that the MAC's are not the best in their performance, but not sure if it's due to the lack of crossover, or lack of backpressure, or what?? They are paired just like the OEM's, just no crossover or fancy multichambered mufflers!

And trying to make a 4-1 collector is much more difficult and $$ than a 2-1. And trying to make the 1-4 and 2-3 pairing like the Jardines also adds more complexity both in routing of the pipes, the angles coming down from the exhaust ports having to cross over/under other pipes, etc.!

I have a 4-1 Mac/JCWhitney set on mine, and I run in the 5+k rpm range alot, and so their improved scavenging affect compliments how I ride my bike. But many folks ride their machines more sedately in the 2-5k rpm range with just the occasional burst to 7+, and so the simpler 4-2 headers are adequate for most performance needs provided they have proper mufflers to supply the required backpressure for ease of tuning.

Again, this is an attempt to see IF replacement headers can be made and be functional at a decent price savings vs. the commercially $$ available ones.

So...this is what I'm trying to do, just trying to show my mindset and thoughts on this project. Keep 'em coming.

[CaptonZap]

Hey Folks,

The OEM design of the headers have the inner section being both flattened so that it's a wider area and at a 45 degree type curve as it joins with the straight section of the outer pipe. My prebent sections are just ROUND, I don't know how well I could FLATTEN that section prior to attaching/welding it to the other pipe into its SIDE, as well as cutting out the matching OVAL shape, and also have enough room to be able to get the TIG tip inbetween the 2 sections!?

One thing to remeber is that if the pipe section is flattened, it is also widened
to maintain the same cross section area, so as not to impede gas flow to much.



See the simple diagram below. First shows the OEM shape. Second shows just joining the pipe using a 90 degree bend.....as variation of this could be done with any angle...the header pipes don't have to be parallel....they could be angled at a slight converging angle to the junction joint, so that the bend can be cut at any angle between 90 and 45. The 3 is cutting and using 2 bends, each 45 degrees of curve, cutting a parallel cut so that both ends could be welded up, and then a hole cut in the joined end to afix the round pipe section that goes to the muffler. This last idea would provide the same bend and theorhetically the same resistance vs. 1 straight thru and 1 having to go around a 90/45 degree bend!?



Okay, thoughts, ideas, etc.?!

T.C.

Here is one way to handle the welding. Cut the two pipes to fit each other, and then weld the adjoining sides from the INSIDE of the pipes, out to where you can get your torch onto the outside. You may have to extend the tungsten out, and use a small cup, but it can be done. If your welds are like mine, you might want to get a half round bastard and clean up the dingle berries.
Then you can weld the collecter pipe on from the outside as well. CZ

[Eveready1100]

You may have to have a look at how much frame clearance will be lost by slinging a full sized pipe under the bottom frame rails instead of the squashed factory pipes from the inside cylinders. I've got an OEM system on my Special and the heat shields ground out quite readily while cornering and the full diameter tube would have to add at least half an inch to what is already hanging under the frame.
Still a great idea though, mate!

[barrelguy]

I could save you some work

by selling you a set of stock original headers from my SG. $50 plus shipping. let me know if you are interested and I can have them in a box this afternoon. I cut off the rusted mufflers just where they joined the collector.

[Rasputin]

TC.
When I said working exhaust I simply meant one that you made that fit, had a slip on readily available (and plentiful) mufflers, had clearance issues like side and double stand stuff looked after etc. If they mount up and the mufflers mount ok sort of thing. If they do all that and get the exhaust from the heads to the rear of the bike well HOORAY!!!.

Once you have an exhaust sytem that works like that. Then you can branch off into more sophisticated systems if you wanted. For lack of better description if you make a set equivalent to a Mac 4 into 2 you win. If after that you can modify or create a better system even better. Many of us would love a new set of pipes. Many more would prefer to have some selection. Good for you to even undertake a project like this.

In my mind, I thought you could buy 2 into 1 and 4 into 1 collectors same as car guys can buy. I thought it may well be cheaper to buy them than the extra work to fabricate something as well as possibly end up with better performance. I am certainly no expert on this type of thing. Speaking only for myself here I would rather pay more and buy a better set of pipes. If pre-made collectors did that then I am for it.

As far as complications go to produce something like spaghetti headers or a similar type, all I can say is, it is a one time issue. Once an experimental system works it is a matter of setting up a jig and the rest falls in place. Do not get me wrong here as I fully realize the work it will take to undertake this. The rewards sometimes outweigh the work put in.

If there is anything I can do to help please let me know. I have some pics here and a few different exhausts I can measure stuff up and send you if needed. Here are a few examples and I have other systems as well but I just have not taken any pics yet. Good luck with this and I am looking forward to reading about your successful venture.

[TopCatGr58]

Dialogue, this is what I'm talking about!

Hey again Rasputin,

Alright, I see where you're coming from, and I agree. Now for some of the research I've done to show why I'm using the approach I am. Thanks for the variety of photos of the different systems. Earlier Eveready1100 posted about clearance concerns, yet the MAC's, the last photo shows the inner header pipe below the outer one that runs along the outside of the frame and they are stacked/positioned on top of each other for frame clearance.
I'm thinking that if Eveready's OEM pipes are dragging in a turn, then he possibly has his machine lowered a bit more than the OEM stance?

GloweVa will be the donor/test machine and he has an old set of MAC 4-2's on his and there seems to be adequate ground clearance.

Okay, we know that we can get a Mac system for ~$400.00...4-2 or 4-1, complete with a muffler, and chromed....albeit single walled which will turn to gold or blue very quickly!

Now, the company that was recommended to me for getting mandrel tubing and such has lots of fancy things like 2-1 and 4-1 collectors, and also fancy prices....see below some examples! Remember, with 4-2 will need 2x the collectors.

Columbia River Mandrel Bending co: www.mandrel-bends.com

2-1 Merge Collector, Splayed, 1.50" Inlets, 1.75" Outlet, Mild Steel 16 ga $52.24


2-1 Merge Collector, Parallel, 1.50" Inlets, 1.75" Outlet, Mild Steel 16 ga $50.34


4-1 Merge Collector, Parallel, 1.50" Inlets, 2.25" Outlet, Mild $175.00


4-1 "FORMED" Collector, 1.50" Inlets, 1.75" Outlet, 5.0" Long Mild Steel $46.00


Collector Bullets 1.50" Stainless, 4-1 16 Gauge, Unwelded $12.10


X-Pipe, Splayed 1.75" Inlets, Splayed 1.75" Outlets, Mild $110.18

SO...now that we can appreciate the pricing of JUST the collectors we'll continue with the project discussion!

The other supply place that was highly recommended and did in fact have great prices was Summit Racing. What I got and their prices is listed below. All items are 16 ga mild steel material...we MAY talk stainless at a later time!!!

1.50" OD 90 degree elbows: $5.95 ea
1.75" OD 90 degree elbows: $5.46 ea
1.50" OD straight tubing 8 feet: $12.15 ea
1.75" OD straight tubing 8 feet: $12.95 ea

I got 8 x 1.5" elb; 4 x 1.75" elb; 2 x 1.5" pipe, 1 x 1.75" pipe, plus shipping fees, total was $134.64...I don't think I'll be using ALL of the elbows and straight pipe, so final headers materials cost will be less. Now just add in the consumables...tig welding shield gas, rods, tungsten tips will be a few bucks more.

Now for more fun....we love pictures, here's a few showing the elbows.





What's interesting about these prebent elbows is that one end is the desired OD...ie. 1.50", however the other end is expanded to 1.62", just big enough for the 1.50" end to slip cleanly/directly INTO the larger end...I'm assuming for adding other pieces and joining..since they are really more for AUTOMOTIVE applications...they aren't worried about appearance and seams showing!

And then a quick mockup of 2 elbows end to end, stuck into the head port and positioned around the engine/frame...with a simulation of where the bottom elbow will be cut to weld on the straight pipe section that will go/be part of the final collector.



Now, I can use either the 1.50" OD end OR the 1.62" end against the head, I'll be putting another layer/ring around the end piece to secure the flange and have something for the flange to pull against to push the header end against the engine/gasket. Using the 1.62" end with another layer around it will make the fitting into the head a bit snug....ideas and thoughts on this vs. the 1.50" size with the 1.62" layer around it.....so total OD going into the head would be 1.62", not 1.75"!

Okay, hope you're enjoying the show and dialogue....looking for more!

T.C.

[CaptonZap]

If anybody is interested in the baffling of an 80 G standard muffler, I took some pictures of the inside of a rusted out one that I cut apart. I could e-mail them as jpegs to someone that could get them on this site. It would be a day or two on my end. CZ

[crazy steve]

I would love to see some pics of the inside of a standard muffler... How about the inside of the crossover? Got pics of that too?

[DGXSER]

Would be interesting to see how the STD compares to the Special one I cut open and posted the pics of.

[Eveready1100]

T.C. Not sure exactly what the oem specs are, but I'm running progressive springs up front with an extra 1/2 inch spacer for extra preload as I don't bother with air and the fork tube caps are sitting flush with the top triple clamp. At the rear, the shocks are KYB 330 mm eye to eye with high rate springs. Maybe just a tad more adventurous than the average Special rider.



I am really concerned about the day that my system does fall to bits and with the only local supplier over here asking something in the vicinity of $1700 for a stainless replica system (sort of), totally out of my budget, something along the lines of what you're undertaking would be contemplated very seriously, so by all means carry on with the project and hope that success will come your way.
P.S. I don't think a Mac system would last very long on my bike. It'd be a spectacular sight at night, though.