Testing the waters: Replacement Exhaust Headers

[TopCatGr58]

Hey folks,

I mentioned in another thread when I talked about getting a TIG, but wanted to create a new thread for dare I say "Opinions"?!

I'm trying to find something that my currently non-employed(x 1 year+) B-I-L could possibly do as a cottage/Garage business and also help out the members with at least 1 unobtanium part!

Replacement mufflers are easy...H-D castoffs as well as new bolt ons from MikesXS and such.

But the crux seems to be HEADERS. I've done some initial research into just the basic supplies....ie. 16 ga mild steel tubing (Cheap) ~$12.00 a 5-7 foot section; as well as 16 ga Stainless Steel(309 or 406) Expensive .....$12.00 a foot.

Crude measurements of my bike/headers shows at least about 3.5 feet needed for each header tube to reach a 2-1 collector. That's 14+ feet, or
~$170.00 JUST for the Materials for SS, not to mentions other materials needed for the flanges, collector, and then S&H!!

SO...at least for now it looks like regular steel tubing will be the first option. To fit most of what I think folks want which is a relatively stock configuration, they would be 4-2 style....still deciding on necessity of crossover vs. just decent quality of bolt on muffler with some back pressure.
Also, the stock 1-2 and 3-4 pairing to keep the bends/manufacturing process as simple as possible, and therefore the pricing as well.

Once folks could get replacement headers as a decent price, then they could opt for the coating of their choice, JetHot comes to mind, as well as Ceramic high temp paint, or even Chrome if they have the $$ for it?

I've got a simple HF style pipe bender NEW STILL IN THE BOX from several years ago...been thinking/planning this for some time, but also understand the pitfalls when trying to bend pipe...kinks and such. Read about some techniques using sand or such temporary filler to help prevent the collapsing of the pipe during the bend process. A 90 degree bend will be needed at the head, then 2 subsequent 45 degrees to get around the lower engine case and such and still keep it relatively close to the engine/frame.

I've got some spare engines and frames for use as mockups/jigs to ensure proper fit. For just the headers and depth/location of the flanges, do I need to worry about Specials vs Standards...I've read that some have shorter studs when trying to fit one OEM onto the other type?

The head opening is 1.25" at the smallest, to 1.62" widest, so I think a 1.5" OD pipe is the right size...my aftermarket 4-1 headers are also this size. I don't have any OEM's to compare. Not sure if flaring the header end is necessary since it's a flat mate surface against the head and header crush gasket.
The collector muffler end looks like the 1.75" is a more common size...at least for the 650, not sure about the H-D's?

Finally, is this something that you all think could be a useful product?
Especially if the price could be ~$100.00 or so for the Headers in Mild Steel?
Depending on ease and success of using Mild Steel we Might venture into SS, but then they would probably be closer to $250.00 or more!!

And would you prefer the 4-2 or 4-1 format? I thought of making a Poll, but decided to ask folks to type/spell out their opinions/input...good or bad, pro or con with regards to this!

T.C.

[natemoen]

I could be but I think I would be more interested in replacement collectors right now just cause i have 2 sets of stock headers and one has bad collectors.

Good idea and a needed thing here in the US.

Also if you did do a 4-1 if it could be made more compact so it didn't compromise right hand leans so much would be great.

[ddragon63]

TC

my only suggestion would be to shop your pipe... that sounds awful expensive for stainless. But I haven't priced it in years and I know that steel is thru the roof right now. If your going to go mild steel you could always go with the "aluminized" stuff. then the only thing that could rust would be your weld areas. the rest will stay pretty well. OR you can use plain old mild steel and coat them afterwards. Ultimately stainless would be the way to go. Most muffler shops use 304 stainless as it less expensive. you get to 309 and above and your gonna put some money into it. with 304 you can use 308 filler which is WAY cheaper than buying 309 to 316 filler. but if your going to combine some 304 to mild steel you'll need the 309 filler for dis-similar metals. JAT

[MaximPhil]

Hi TC,
My thoughts on exhaust systems.I prefer the 4 into 2 stock appearing configuration. The 2-1 collector is going to be a challenge to get right for flow and fit. alot of comments over the years lead me to believe the cross over is an important part of a smooth running engine. In my opinion (you did ask ) essential. I think the Standard vs Special is an issue with hanger location and a careful design could be built to fit both and the 81H.
Phil

[crazy steve]

TC, not to rain on your parade, but before you get everyone all excited you need to check out a few things....

While I've never bent any exhaust tubing, I've bent literally miles of conduit in my 30 years of electrical work. While not quite the same thing, the principles/techniques involved are and there's a reason few people build their own exhaust systems. I had access to some pretty nice benders, but none of them would have built a motorcycle (or car for that matter) exhaust system.

Every motorcycle exhaust I've ever seen is built using mandrel-bent tubing. A mandrel bender is an expensive, specialized tool designed to bend pipe with a minimum of deformation. These use special shoes and rollers to draw the pipe through the bending process. One design hallmark is these use two shoes (one on each side of the tube) to do the bend. The cheapest one I found was this one... http://www.restockit.com/tubing-bend...ci_sku=NCT5989 ... but I doubt this would give a smooth bend like you'll find on commercially bent pipe. For that you need precision-machined close-tolerance shoes. If you check at a muffler shop, you'd probably be looking at no better bends than what they could do. In a short-radius bend, it's extremely hard to get a smooth, lump-free bend. The factory and aftermarket manufacturers are using many-thousand-dollar benders to get the result you see.

The benders HF sells are all 'segment' benders, designed to bend heavy-wall pipe (3/16" or thicker), a little bit at a time. One big problem is they're fixed-radius (a minimum radius for a given size), so in a 1.25" or 1.5" pipe you're looking at at least a 12" minimum radius, and even that will be very tough to achieve without kinking. To bend thin-wall tube, you need a 'backing' shoe to prevent kinking. The bender design for thin-wall is completely different. With a segment bender and thin-wall tube, you'll be lucky to be able to bend more than 1-2 degrees at a time before you start kinking/crushing the pipe, and after making multiple 'shots' (bend a few degrees, then move your bend point) you'll end up with a 5' radius... at least.

I've probably tried every 'improvised' pipe bending method there is (wish I had a dollar for every time I was out on a job and didn't have the 'right' bender and had to 'make do'...), but there's simply no way to get the short-radius bends you need to fit a motorcycle exhaust without a mandrel bender, and if you don't want the bends 'lumpy', you'll need a big-bucks pro unit....

[Poprock]

Bummer! Just what I was getting excited about the possibility of new 1-3, 2-4 header pipes as an option.

[jetmechmarty]

http://www.xs650exhaust.com/

If someone like this can be convinced that there's a return for the effort, it can still happen.

[TopCatGr58]

Hey Steve and others,

I appreciate the tech info and actually understand what you're saying about the bending process! I'm not down yet! I may be able to get the bending done by a local muffler shop for nominal fees? Also, I've found sources for obtaining PREBENT Mandrel bends...90, 45 degrees, etc., but this would then entail more cutting and WELDING having to join the bent pieces with straight sections!

You guys mentioned the problem area would be the Y connector or transition? I've seen the stock pipes, are you worrying about ground clearance, or tuning depending on if the crossover is built into the design?

I've read where folks were not too impressed with the MAC's but not sure if it was due to the SOUND, or performance? They don't have a crossover section.

As to the 4-1 type, the problem I've seen and experienced myself has been with the low position of the actual MUFFLER, not the 4-1 collector. SO having a modest angle in the final section before the muffler should allow it to be mounted with a bit more of an upswept position?! IF ground clearance of the actual 4-1 collector has been a problem, then I would think that a modified 4-2-1 would be needed so that they could all be positioned sideways instead of stocking 1 on top of the other. But that would/could then create a different tuning scenario..headache??? I don't have a flowbench or such apparatus...mostly would be "borrowing" the dimensions from the OEM pipes and such.

Poprock...the Spaghetti 1-3, 2-4 or 1-4, 2-3 combo is probably beyond our capabilities!

T.C.

[Rasputin]

Every used 4 into 1 I have seen has had the damage to the bottom of the collector. I have yet to see one where the muffler was damaged. Might just be me but I have a couple here that are pooched at the collector.

[Poprock]

Had a Mac 4/1 on a XJ650. It could hit, but it also helped the bike out a lot over the dual straight pipes it came with. Big power above 5000! My XS11 had a stock system that rotted out. Replaced old muffs and crossover with 2 Harley Sportster muffs, no crossover. I have noticed no degradation in performance sans crossover. No re-jetting was necessary either. Sound level is about the same as stock, slightly lower pitch. Works for me. Makes me think a crossover may not be a deal breaker if they're hard to fabricate.

[natemoen]

Every used 4 into 1 I have seen has had the damage to the bottom of the collector. I have yet to see one where the muffler was damaged. Might just be me but I have a couple here that are pooched at the collector.

when I had a 4-1 on mine last summer it was some of both, probably lost 2" ground clearance at the collector but then in the twisties I would catch the muffler.

[jetmechmarty]

With my new springs, I don't hit the collector any more.

[fredintoon]

Hi T.C.
kudos for trying to help your b-i-l.
If you could gather up enough money to buy the kind of thinwall tube bender needed to make those tight curves your b-i-l could retire on it; those things ain't cheap.
The alternative of welding up pre-bent segments to lengths of straight tube can make a working set of pipes but they'll look like bamboo.
OK, setting up as the local "Bro with TIG welder" can work if he's careful about the jobs he'll take on but I don't see handcrafted XS11 exhausts as a road to solvency.

[crazy steve]

... Also, I've found sources for obtaining PREBENT Mandrel bends...90, 45 degrees, etc., but this would then entail more cutting and WELDING having to join the bent pieces with straight sections!

A lot of the custom bike pipes you see are made that way; the only downside is a tendency for cracking at the welds, but doing the welding with a TIG helps with that. Luckily, 1.5" is a common header pipe size. I doubt if you'll have much luck finding a muffler shop that can mandrel-bend anything that small though, as 2.5" is usually the smallest size a local shop can do. You could go smaller with a 'standard' muffler pipe bender, but you'll get fairly lumpy bends....

[EricHa]

Hey T.C, I would like a 4-1 setup, with oil filter access, and centerstand retention. If a megaphone was doable, a short one like the RC headers would be cool, with a diameter that would allow use of a Vance/Hines, Kerker or MAC baffle. I have some old stuff laying around if you needed anything for reference.

Here is a decent site for tubing:

http://www.mandrel-bends.com/catalog/