New Build, relatively new to the Forum...a few questions (Pic heavy)

2door said:
This is a little late but in case you want to try again I'll suggest you leave more pipe from the flange. Retain some of the bend that was already there and that means you don't need a complete circular bend in the EMT.
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I actually tried that at first...I had a good line/bend until I kinked it...and at that point I thought it would look cleaner if I had one lone pipe as appose to connecting further down, so I cut it then. If somehow I ruin the welding process, I'll order another one and start over. :)

2door said:
As for connecting the conduit to the exhaust pipe, here is another suggestion. I 'swedge' the EMT. It doesn't take much to get it to slide over the pipe material and all you need is about 1/2". I TIG weld this connection using stainless steel filler rod. Of course I realize everyone doesn't have access to TIG and it isn't necessary. Your idea of brazing will work, just not as pretty. There are 'swedging' tools available but I made one from a pair of battery cable terminal spreader pliers. I heat the EMT then insert the pliers and squeeze while rotating the pliers inside the EMT.
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That's a great idea! I'll have to look for a tool...or home made remedy, thanks!

2door said:
Just in case you don't know this (if you do, sorry, just need to include this) But welding or brazing on EMT will expose you to potentially toxic vapors. The galvanized plating is not good stuff to breath when it is heated. Do it outdoors and with good ventilation.
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Yes, thank you! I have read up on that very issue... I have a great vented mask (I use for paint/epoxy/fumes)...but am trying to avoid it brazing if possible. I may just take the pipe to an exhaust shop and have them weld it and be done with it.

2door said:
Your idea to use conduit connectors might work but keep in mind that the 'stop' or that stamped ridge at the center is a weak area and prone to breaking under stress or vibration. Just be aware.
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Thanks, I wasn't aware of that. I will need to look more into the swedging concept I think.
 
With all of the advice I gave you above I forgot to mention that the pipe you've built looks good and should function well. I've used the same method, EMT and stock pipe/muffler combinations, on several bikes and have been pleased with the results.

The 'high performance' guys will 'poo-poo', no pun intended, on the design but for everyday street riding they will perform just fine on a Chinese 2 stroke engine. One real advantage is they put the noise and exhaust behind you. I think you'll be pleased with the sound from your engine. Now you'll start looking for ways to quiet the 'pop'pop' intake noise. :)

Tom
 
Ha ha! You're so right... can't believe how loud the engine itself is...never noticed it until the exhaust sound went to the back. It's a joy to ride...just took a 3 mile trip in the neighborhood to test it out some more.

I like it! It's fun, much more quiet, but I'm gonna have to fix the seals on the exhaust, no way around it. They've broken loose/and I'm getting oil/smoke out of them now. I have to either buck up and get some brazing gear...or get it welded... shouldn't be hard either way. :)
 
It's been a little wile since I've updated on this build, so here's a snapshot:

Over the holidays I've been running the bike with the new exhaust I put on. A few thoughts on it: I like it. It runs more quiet, and seems to help with overall performance. However the connections I've used are not as solid as I'd like and has too much play, causing it to rattle and let's exhaust out of the seams... the only solution is to either buy a poo-poo pipe (I like the look) or to weld/braze the pipes together.

Before I spend on a new pipe, I figured that I might as well learn to weld. LOL

I assume with the thinner metals, brazing may be the best way to go...but getting a decent oxy/fuel set up is expensive!! I inititally tried to braze with Mapp on some scrap pieces...and I just didn't get hot enough.

For Christmas, I got a little arc welder (Mig or Tig would be much better I think)...but I can convert it to Tig if I want down the road. I'm practicing with it and welding up things left and right!! It's pretty fun...not sure why I didn't get one earlier. For the EMT/pipe connections however, I made a few passes on some practice pieces and while it welds...getting the settings low enough to not melt through the EMT is challenging. Not impossible, but not an easy job and NOT pretty.

I'm going to take this month to practice until I feel like I've got it down and then I'll do the actual pipe. If all else fails, I can always buy the poo-poo pipe...but what's the fun in that?

Meantime, I've got new jets to play with on the carb (Once it's fully broken in) and I've ordered up a seat post from a member on here...hoping to get it this week sometime.

Next up will be starting to work on the tank I'm going to build.... I've gone back and forth on designs but I think I've finally settled to go with one that works best with the frame of the bike.

I'll post pics when I've actually done some work.
 
Good that you're practicing on the thin metal welding. I was once told by a 'professional welder' that TIG welding EMT was impossible and that I was full of BS. HA HA.

No, it isn't impossible and it doesn't take years of practice to accomplish. Keep at it, Brass, and you'll get the hang. It can be done and some very nice welds are possible.

Glad you're making progress. Thanks for the update.

Tom
 
If you have a stick welder try some 7014 rod,its a contact rod and you can hold it against the work and go right along..................Curt
 
Update on welding the exhaust... I've found that you can indeed arc/stick weld thin galvanized steel...like 3/4" EMT tubing. The way it worked for me was to use 6011 rods (DCEP) at about 35 Amps. Once I get the arc started, I then take another 6011 rod (shave all the flux off) and add it to the weld joint where it inevitably melts and binds the pipes... interestingly, by doing this it takes the brunt of the arc (Or so I assume) as it didn't burn holes in the EMT nor exhaust tubing pieces...where I was careful and slow...when I went too fast, and didn't add enough of the sacrificial rod I got melting EMT, etc... Anyways, it's possible with patience and practice. (BTW, I saw this on youtube for welding mufflers and essentially copied it). Thank you Youtube! :)

That being said, I need way more practice to get good at it...and being the impatient SOB that I am, I decided to go the brazing route...LOL. Job done and spent the weekend priming/painting the exhaust high-heat black. (I know galvanized steel isn't likely to work well with paint, but we'll see how it holds up).

Here's a pic of it on the bike:

Thanks!
 

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Good job, Brass. Incorporating the tensioner with the muffler bracket was a good step.
Congratulations and thanks for sharing it with us.
Your bike is looking nice.

Tom
 
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