Title Bits

Arrrrr-gon, I was lacking a clever title so I thought I would tell one of my very own homemade pirate jokes. Here is another one. What do pirates take on vacation? an Arrrrr-V. Lets move on shall we?

I had taken on my CB160 cafe racer project as my main garage focus and continued to do little side projects in between. It would appear that my 65 Revive project is starting to become the side project as I continue to get side tracked with numerous project that seem to be taking up the majority of my time. Either way I continue to stay focused on the Honda build and still make progress using what little time I can find.

I decided it was time to tackle the exhaust. There was no reason why the exhaust was the next required step it was a decision based purely on what I felt like doing. I had already mentally designed the system and had ordered all my stainless steel mandrel bends from Columbia River Mandrel Bending as well as my muffler from Megs Mufflers. As much as I would have liked to just jump in and start seeing the system come to life there were necessary preliminary steps that needed to be performed before the `glory`work could commence.

The original header pipes had flanges bent into the tubing in order to allow for a gasket surface as well as a way to secure them to the cylinder head. I had played around with a few ideas as to how I would accomplish this on the new stainless pipes and had finally settled on machining some flange rings that would get welded onto the down pipes.

Another item that needed some attention before fabricating the entire exhaust were the factory cast finned flanges that secure the exhaust to the cylinder head studs. Since I was building a fully welded 2 into 1 exhaust system I needed to thread the flanges onto the exhaust downpipes before welding up the system. The flanges would be permanently installed onto the exhaust system therefore I needed to perform final finishing of the flanges.

So I`ll let the pictures walk you through the details. So far everything has worked out perfectly and I look forward to seeing the exhaust system take form.

OEM Downpipes

These are the factory downpipes for the CB160. You can see the pressed flanges that fit into the cylinder head. The orignal set up was a dual exhaust however I have opted to change things up to a 2 into 1. Using Megs Mufflers collector size chart I opted to feed the factory 1.250″ primary pipes into a collector with a 1.50″ outlet.

Machining ex flange

In order to get the flange I needed on the primary downpipes I decided to machine them up. Here is the finished machining except for the trimming to length.

Header pipes with rings

Here is a shot of the 2, soon to be, new downpipes with the freshly machined flanges ready for welding.

Press fit flanges

I machined the flanges with a very slight interference fit in order to help hold them in place while they get TIG’d on. The fit is fantastic.

Doin what I love

Laying down the molten.

Ex flange weld

All welded from the inside, no clean up required. I love welding staniless.

Powdered ex hold downs

Here is a shot of the factory finned exhaust collars that secure the header pipes to the cyclinder head. Since these flanges will be an integral part of the new 2 into 1 exhaust I needed to clean, glass bead blast, and powder coat them. I ordered in high temp powder coating just for this occasion.

Trimming mandrel bends

Trimming up all the mandrell bends on the bandsaw makes the fittment so nice, all the cuts are square and the joints fit up perfectly.

Argon feed

Thought I would show my stainless steel wedling set up. Since stainless “sugars” so badly on the back side of the weld it is important to back purge it when it welded. This simply means that argon needs to get pumped not only on the top side of the weld but also on the back side. I built my own back purge set up. I added a Tee fitting to my argon regulator and attached a ball valve plumbed with a 1/4″ pneumatic airline.

Back purge valve

I then run the 1/4″ pneumatic airline to a regulator and another ball valve. I made this little unit so I can clamp it to my wrok bench near by where I am welding therefore it is quick and easy for me to control the valve before and after the welding.

Pipe purge plugs

I use surgical tubing from the work bench mounted valve to a couple of silicone plugs. I stole the plugs out of my powder coating kit. I drilled holes through the center of the plugs and inserted an air needle used for filling up sports equippment. One plug acts as my inlet and the other is my exhaust.

Ex set for tacking

Here you can see the set up in action. I simply feed argon into the pipe and allow all the air to exit the other end. Once the pipe is filled with argon the welding can take place and sugaring of the welds backside is prevented. It uses up the argon a little more quickly however it is worth it considereing the weld quality it produces.

Mocking up 2 into 1

And here it is. All the prelimary leg work completed. It may not seem like much but it is a required step on my way to getting the complete system fabricated. Now I am able to get onto the actual forming of the sytem.

Comments
  1. Luis Rodrigues says:

    Nice!!! And what about the starter and the crankcase? Are they gonna be like that or will you do something to them later on?

    • gordsgarage says:

      Thanks Luis, the engine that is currently in the bike is only my mock up engine. The engine is empty and there is hole punched through almost every piece of that engine. My good engine is sitting on a stand under a sheet waiting for the bike to get finished. You can see it here

      Thanks!
      Gord

  2. Steve says:

    Don’t forget the flanges before you collect, haha
    Keep up the good work

    • gordsgarage says:

      Hey Steve, that would suck and would maybe even bring tears. The good news is I have made progress on the exhaust and I did NOT forget the flanges first. I’ll post pics soon.

      Thanks!
      Gord

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