New pipe setup.

Easiest thing to get is steel conduit tubing from home depot or lowes etc... you can buy pres bent sections but they're usually bent in a really wide radius.... this stuff can be welded or brazed into place for a more permanent and clean looking install.
If you cant weld or don't have access to a welder you can braze with a mapp torch and some brazing rods, the connection is very strong when done right, but the best part is it can be donenat home with no need for pricy tooling...

I like to use regular flexable exhaust pipe that I bought at an O'Riellys auto parts store, What I use is 1"ID which is a bit large for use with the Sick Bike Parts tubing unless you wrap the smaller tubing to enlarge it so it will fit the larger ID flex pipe.

Like Dave said, Home Depot and the like have the flexable conduit that can be used also.

2door said:

Shan,
I think Dave was talking about EMT, conduit. Not flex. Flexible conduit will leak badly. It won't contain liquids or gasses.

3/4" EMT lends itself nicely to custom exhaust systems. It can be bent and welded, or brazed, and is light and, if you feel so inclined, can be polished to look almost as good as chrome. It doesn't hold the shine permanently but once buffed the shine can be brought back with just a little elbow grease and metal polish. I use TIG to weld it and a conduit bender to make those swoopy curvy bends. He also mentions the pre-bent sections. Usually they have a tighter bend radius than you can get with a bender.

Tom

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Thanks Tom, yeah after reading Daves post again I realize now you're right.... my early morning mistake.....lol!

For some reason what I had in mind at the time was the header pipe xseler made for his bike from the flexable copper hotwater heater tubing, you're right flexable electrical conduit wouldn't be good exhaust pipe at all.

2door said:

Shan,
I think Dave was talking about EMT, conduit. Not flex. Flexible conduit will leak badly. It won't contain liquids or gasses.

Tom

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Watertite flexible conduit works just fine to contain liquids or gasses.
Just strip off the plastic coating and the inside is pretty smooth.

Stainless steel flexible conduit bends tighter, is stronger and was used
on the original Whizzers for their exhaust tubing capped with a fan tail tip.

Gas line flexible tubing has corrugations that would not be good for exhaust flow.

MotorBicycleRacing said:

Watertite flexible conduit works just fine to contain liquids or gasses.
Just strip off the plastic coating and the inside is pretty smooth.

Stainless steel flexible conduit bends tighter, is stronger and was used
on the original Whizzers for their exhaust tubing capped with a fan tail tip.

Gas line flexible tubing has corrugations that would not be good for exhaust flow.

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great tips Neil.

Yeah I wouldnt personally use water heater flex tubing because of the reasons yo7 descri ed but some have.

VenturiEffect said:

Im going to look into.the conduit. My engine seems to.be.running hot. Ive only had it.for maybe a month. Could it be the warmer weather?

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Check the color of your spark plug to make sure its not running lean.

although there are factors such as fuel quality that can affect color we normally look for a light to medium brown plug color.

Yup... I was talking about the EMT piping you can buy at hardware stores... it's regular steel and it brazes or welds easily... As for the flexible piping, personally i try to avoid it in my builds but others have had success with it, and it does look cool when done right. They do sell pre bent sections of EMT but a 1" 90 degree bend has like a 5" radius so the bends are really wide. To get around this problem, a straight or bent section can be purchased, then pie sliced and re welded or brazed to get teh bend radius or shape you need. The advantage of pie slicing is that you keep the same diameter across the bend like mandrel bending, but the disadvantage is that there's a LOT of cutting and welding involved. Pie slicing and welding is not a way to do a 90 degree bend, but you can get a very tight radius by doing 9 10 degree bends or 10 9 degree bends...
Tools needed for the pie slice method are a chop saw or a die grinder and a LOt of cutting wheels... the 3M brand "Green Corps" wheels are the thinnest and last the longest. I get these in 5 packs and they're 3" dia x 1/32" thick, and one wheel will make several cuts before wearing down to the point it's not usable. For comparing, the Harbor Freight cutting wheels are 3" dia x 3/64" (nearly 1/8" thick) so they cut slow and will wear out in 2 or 3 cuts thru 1" EMT... get the good stuff.
Also when pie slicing to get the desired bend angle, there's no need to cut all the way thru a piece of pipe, you can cut out a very thin slice but leave just the outer wall intack and fold the pipe til the gap closes and weld or braze shut, this way is easy for anyone to do and also reduces the time it takes to set each section up for re welding etc...

2door said:

How do you plan on attaching weathertite conduit to anything with the plastic coating on the inside? Welding it? Yes it might hold liquid and gas but it's stainless steel. You can't solder it, you can't braze it and only those with skills could weld it and then there goes the coating so you have a leak.

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"Weathertite" flexible conduit is made of steel and the plastic coating is on the outside.
You slit it then peel it off like a banana skin.
Check it out when you are in Home Depot next time.
Why would the liquid tite coating would be on the inside?
It's flexible conduit for electrical wires.

I have used both kinds as exhausts on 4 strokes.
The flex tubing is clamped onto an exhaust stub which is how the Whizzers did it.
No welding needed.

The stainless flex is sealed by it's tightly coiled interlocking construction. It is so tough that you can't break it by bending it as tight as it will go, which is about a 6" diameter for 1" OD.

The steel flex will pop if you do that to it.

MotorBicycleRacing said:

Gas line flexible tubing has corrugations that would not be good for exhaust flow.

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I totally agree it would be a epic fail to a otherwise what could but will now never be a perfectly ''tuned'' expansion chamber. IMO.

the exhaust Im making for the Yellow bike is 1" ID flex exhaust tubing I bought at an auto parts store, its just galvanized steel and seals off perfectly.

its kinda hard to find it seems and some places that have it want way to much for it in my opinion, Im gonna go to Home Depot and look at the flexable conduit with the out shell, I always thought it had an inner coating also, but if it doesnt then I can see how it would be a good candidate for exhaust as long as it is made in a way that its air tight in the flexing areas.

I also have some of the EMT conduit and have us3s it for exhaust, I have a tubing b3nd3r for 3/4" but not for the 1", I tried bending it on my HF pipe bender but it just mashes flat and tries to crimp over since its so thin, for some reason the 1" conduit benders at Home Depot are much more expensive than the ones for 3/4" cant figure that one out......

Have you tried filling the emit with sand and packing it in tight before bending? Or does it still try to smash flat when bending?
I haven't tried to bend any small tubing on my new HF pipe bender but I did get a successful bend on some 1 1/2" steel pipe by bending it the desired angle then taking the pipe to the press to push the bent section down to where its even with the rest of the pipe, still not as nice as a mandrel bend but nicer than just bending it in the bender, I still need to get a few bags of sand to see if filling the pipe with sand will help keep it round at the bend.

Davezilla said:

Have you tried filling the emit with sand and packing it in tight before bending? Or does it still try to smash flat when bending?
I haven't tried to bend any small tubing on my new HF pipe bender but I did get a successful bend on some 1 1/2" steel pipe by bending it the desired angle then taking the pipe to the press to push the bent section down to where its even with the rest of the pipe, still not as nice as a mandrel bend but nicer than just bending it in the bender, I still need to get a few bags of sand to see if filling the pipe with sand will help keep it round at the bend.

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No I haven't tried that yet but its a plan, Im gonna get some 1" and try that, I know there's a thread on here where many of us discussed several ways of getting the pipe bent without crimping it.

I even thought about filling it with sand and then adding water to get the sand very densely packed to see if that may help stop the crimping issue.

Im gonna go to Home Depot tomorrow and get some 1" and I may pick up a sack of play sand while Im there and give it a try.

Just to answer the question before it gets ask by someone, I plan to cap the ends by drilling through the very end of the tubing capping it with either cast or pvc caps that have been drilled also then Ill just sput a #8 or #10 machine screw through to hold cap on.

Yup... that Cerro Bend stuff is the best thing to use if one can get it in the right amount to fill the pipe to be bent... I've seen that stuff before and it basically turns a tube into a solid piece until you melt the stuff out, and it can be reused over and over. I've heard some of these super low melt alloys can get ruined if they are heated too hot and it will raise the melting point beyond an easily usable temperature. Not so sure if that holds true for the Cerro Bend stuff or if it's just certain alloys designed to melt at or below 200F...

bo7ght a roll of the flexable liquidtight steel conduit toda6 at H.Depot, $50 for 25ft but its gonna be excellent for making 3/4" ID exhaust, looks identical to standard galvanized exhaust flex pipe once the sheathing is removed, basically $2 per ft. and thats much less than I paid for the 1"ID flex pipe at autoparts store.

Ill post some pix later on tonight when Im on my computer.


And yes, o heat on psealed pipe with wet sand.... big no no....!

That is why I made it clear how I would likely cap the ends.

Same here... I was working at Boeing and was waiting for a tube to be maid to replace a hydraulic line on a KC-10, the guy from the tubing shop let us go in and watch as he did the bends... he basically wanted us to cut out the bad section of tubing so he could copy it and he had me and another guy help him thru the process. I was amazed at the time how easy this metal would melt and he'd fill the tube up with the stuff while it was in boiling water, he did all the bends, then heated the tube up again and this metal just poured right out like water. He told me it could be reused indefinitely as long as ya kept the temperature under 400 degrees or so, but once it got too hot it would lose it's super low melting temperature. They make another metal called cerro Safe that melts at 281F which doesn't contain cadmium or lead and the Air Force was wanting to make them use this stuff since it's safer to handle but since it needed about 90 or 100 degrees higher heat to melt nobody really liked the stuff since they could no longer just dip the parts in a vat of boiling water.
I was looking on ebay yesterday after being reminded of this stuff and there are a few sellers who still sell this stuff that melts at 158 to 190 degrees, the stuff is rather pricy at around $29 per pound but one seller has a 7.5 pound ingot and I bought it for $70 since I need to make me a new lower frame tube for my bike and it'll also get used when making the exhaust for my Stingray build I'm slowly working...