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Discussion Starter #42 (Edited)



Coming along OK.

The comment I made about making sure you match the cut angles is not really possible unless you are absolutely perfect guessing the angles needed and perfect in the assembly of the wedges. Which I am not.

So, in the assembly, there is some rotating of the segments to fit the path you want for the exhaust as close as possible. That means a very minute amount of mismatch in the inside exhaust path but it seems insignificant.

I think for the major bends, you should keep the cut wedges lined up and oriented as best as possible, otherwise you get a very wiggly exhaust line that looks kinda shitty.

For example, parts of this exhaust look wonky to me.
IMG_6655_zps0c8e7a50.jpg

Between the major bends and maybe one wedge inbetween, rotating the wedge to fit the path was a neccesary compromise for my first attempt...
 

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The discouraging thing is that it doesn't look like they touch those welds with a grinder.

practice makes perfect... or a machine does
 
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Discussion Starter #45
I don't plan on touching mine with a grinder either.

Either I get better or it is what it is.
 

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The discouraging thing is that it doesn't look like they touch those welds with a grinder.

practice makes perfect... or a machine does
Tig weld, tight fit, no filler, weld positioner.

Cold welds also sit on the surface, you might need more heat or slower travel speed. Usually novice is too cold but you haz will tell you that.
 

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Discussion Starter #48 (Edited)
Good place. Made a collector from their kit.
It was OK...





An even cheaper place to get mandrel bends and collectors is SPD. I think they are one of the suppliers for Cone Engineering.


Like I've said before, the problem with mandrel bends is that you are limited to one or two centerline radius only. In my exhaust, the 1 3/8" only came in 2.5" CLR. The stock exhaust had a much larger 3.5" CLR.
With the pie cuts you can also alter the radius within a single bend if you want. Once you get the technique down, it's a very flexible way to make an exhaust. But it's not for most, obviously.
 

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looks really good.

I like the braced swingarm.

you should invest in black zip-ties. They are specifically for badass motorcycles.
 

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Discussion Starter #51 (Edited)
Decided to go ahead with the midpipe to lock the path of the exhaust down before messing with the other two pipes.
Just waiting on the muffler, now. A Hindle classic line exhaust.
Hindle exhaust is a megaphone type 16" long. I mocked up the exhaust in the pic below with a 12 or 13" straight pipe 2" diameter.



The midpipe is pretty cool. Modeled it up in solidworks and printed out templates. Kept going back to adjust the angles and offsets until I was happy.
You could have done it with paper and pencil with a protractor and compass, too.




The back end of the midpipe is still mocked up with tape pending the exhaust arriving.
Those wires above the collector will be relocated above the crossmember of the frame.
 

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Discussion Starter #53 (Edited)
That's coming along nice.

Are you using the 4T header pipe software?
No, I thought about downloading Larry Meaux's Pipemax program (I still might) but instead just ran the engine numbers through some calculators at Wallace Racing. Came up with header diameter and length of primaries.
I didn't make an all out HP pipe and kept the pipes actually on the smaller side 1 3/8" with a nice long primary length of 31".

I was limited on the collector size by what Cone engineering had in stock. Three 1.5" into a 2" outlet. (Certainly didn't want to pay $300+ for a custom one from burns stainless for my first attempt.) But since it's a 120 deg firing triple, the exhaust pulses should be separated enough not to cause that much flow overlap.
 

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No, I thought about downloading Larry Meaux's Pipemax program (I still might)
I might have a look at that.

I've noticed that if I don't tig for awhile I kinda loose some skills (the minor ones I had). I don't know if it's the cheapo tig welder I bought a long time ago or my lack of practice or both. It's hard for me to spend the good money I understand I need to spend for proper equipment when it's just to goof around with.

When I get back to tigging more I'm going to make one like your doing.
 

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Discussion Starter #55
I don't know if it's the cheapo tig welder I bought a long time ago or my lack of practice or both.

When I get back to tigging more I'm going to make one like your doing.
If it really is a cheapo tig welder, even the best welder is going to have trouble welding this thin walled tubing.

It really pays to get a decent unit stable at low amps.

Do it. It has been fun once you get the hang of cutting and fitting.

Metal chop saw, 6 in disc grinder, curved files to debur the inside of the tube.
 

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I'm curious as to how much it would cost to TIG up an exhaust this way compared to buying one already done? I mean, how much does it cost for consumables like gas and wire....how often do you need new tips, etc.....

Dont get me wrong - I love the fact you're doing it - just curious on cost.
 

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Discussion Starter #57
Yeah, I agree, no way would I spend time and money doing this if a quality aftermarket exhaust existed for this bike.
The stock system was grounding out on the track. the MAC exhaust I bought used was even worse ground clearance wise.

As far as costs, after the initial equipment investments, it's really not very expensive.
Tungsten lasts forever unless you really suck. Filler wire is cheap. Argon can be a real cost, but there are ways to conserve here.
So far, I've used only one 3 ft length of 1 3/8" tubing and 1/2 of the 2" tubing and I'm done with the midpipe and one header pipe.
Collector kit was about $100, I think. Maybe less.

The real "cost" is time. Cutting, deburring, cleaning and set up and welding all takes time. Each one not a lot but when you are doing it 50 times, it adds up.

The XS750/850 is not a racebike by any stretch of the imagination, so there are no racy parts for it. I would have never tried this if there were. But in the end, I'm glad there wasn't. This is another bike building skill to learn.


Another thing is that once you have the technique, making a Titanium exhuast would only add a little more to the cost over even say mild steel.
 

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I'm skeptical that titanium tubing would add only a little cost over mild tubing. Even stainless steel is expensive.


Sent from my iPhone using Tapatalk
 

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Discussion Starter #59 (Edited)
Sure when you compare the tubing costs it is many times more expensive.

But when you take into consideration the retail cost of a full titanium exhaust system is in the thousands, the 4 foot length of 1.5" tube for around $100 is nothing.

Now a titanium collector. That's another story I guess.


Difference between mild and stainless is less than $15 per 2 ft. Collector is $30 more. Insignificant.


For my first try, I decided to just stick with mild steel. SS and Ti increases cost and complexity with proper purging, though.
 
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