Posts Tagged ‘custom exhaust’

Title front end

So I was able to continue my auspuff progress on the CB160. The preliminary leg work had been accomplished and it was time to start cuttin’ and buttin’ stainless pipe together to make a structure that will hopefully represent a 2 into 1 exhaust system.

The plan was to make the “lines” of the exhaust flow with the bike and give it as much of a clean look as possible. I continued to work with the bike turned upside down as I had previously done when modifying the center stand. I am not sure how much I can say about the whole process other then it takes a lot of “looking” and “figuring” to make sure everything is just right.

I have included bonus pictures in this particular post which shows a major screw up on my part. I was able to dissect my mistake and fix it however the thoughts associated with my lack of planning still continue to haunt me. Anyway…look on and follow along as I eventually ended up with a completed exhaust system for the 65 Revive project.

Tacking down tubes

Laying out and tacking up both header pipes to ensure that they are both identical.

Collecter tacking

Tacking the collector to the 1.500″ outlet pipe which will help me line things up on the bike.

Collecter to headers 1

Starting to piece the header pipes to the collector assembly.

Tacked pipe take 1

Here is the “2” into 1 section all tacked up. I placed the collector in a particular spot in order to allow access to both oil drain plugs.

Ashamed and embarrassed

And here is my screw up. I cannot believe that I did this. For some reason I neglected to presicely place my collector assembly. I have no idea why I just “guessed” at its position. As you can see the exhasut angle under the bike look hideous.

Starting over

So here is attempt number 2. Good thing I only tacked the pipes together. This time I measured and clamped the collector assmebly in its proper position.

Collecter to headers 2

With the header pipes measured out and bolted in symmetrically and with the collector placed properly I began cutting pipe and fitting pipe in order to join the 2 sections together.

Tacked pipe take 2

It’s already looking better. Hopefully round 2 will prove to be successful.

Yeah Baby!

Way better, completely happy with the “angle on the dangle” on this one. The flow looks great. I like how the lines of the underside exhaust matches the angle of the seat frame.

Pipe final welding 1

With the exhaust tacked and tested it was time to perform the final TIG welds.

Pipe final welding 2

I back purged all my welds and they all worked out fine.

Muffler angle mock up

It was time to keep going with the elbow and angle required for mounting of the muffler. Here I used various supports to help hold the muffler in place so that I could stand back and get a good visual.

Completed 2 into 1

With the muffler angle figured out I cut and welded the remaining pipe. With the exception of a support bracket this is the final product.

Pipe install 2

Here is a shot of the completed and installed exhaust. I think the lines and shape worked out great. Don’t mind the orange elastic bands as they are only there to keep the exhaust flanges from sliding down the pipe while I was welding and installing.

Pipe install 1

And here is the final look. I still have yet to weld, or clamp, the mufller (I haven’t decided yet). I also need to install a bracket however this too has to wait for variuos reasons. My intent from the start was not to grind and brush the welds. I wanted to go for a raw and racey look so I think I am going to leave the welds exposed. I’ll let it sit for awhile and see how I feel.

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.

A friend of mine has been working his way through a Honda CB350 café racer project over the past year. He was at the point where it was time to fabricate the exhaust system. His plan was to custom build the entire system from scratch except for the mufflers. He had asked me if I would be willing to give him a hand in completing the task. No problem on my end as far as the willingness goes however I do not have a lot of, I mean any, experience in building custom exhaust. We figured that if we put our heads together we may be able to fabricate something that resembles a corridor for carbon monoxide and hydrocarbons to travel through.

The exhaust system was going to be built from 1.50” x .065” stainless steel exhaust tubing. He had previously purchased various sections of both straight pipe and mandrel bent 45 degree, 90 degree, and 180 degree sections. For us it was a matter of figuring out all the angles and where to cut them. The idea is to TIG weld tack it as we go along then perfom final welding one mocked up.

So he hauled his bike over to my garage and we set it up on a couple of saw horses so that the underside was completely accessible. Unfortunately it is hard to apply any kind of math to this type of procedure. Keeping the exhaust system lengths equal between cylinder 1 and cylinder 2 is important however figuring out all the bends needed to be done by eye. So between the two of us we spent much time holding up pipe and staring at it. My friend has a very good eye for angles and appears to be able to envision the system as a whole much better then I can.

It took an entire day but we managed to get the entire system mocked up and tacked together. I am happy to say that no wrong cuts were made and no welds had to be cut apart for a redo. The symmetry came out fantastic as it aligns great with the lines, and frame, of the bike. All that remains is some time spent performing the final welding. After the exhaust was complete we even found some time to fab up some rear mounts to relocate the foot pegs and foot controls.

The pictures on this post lack some of the specific build details, my apologies. When working with a second person in the shop it is hard to take time out for getting shots of the process. You get what you get and will have to piece the story together for yourselves. Enjoy.