Hawk Exhaust HACK Mod: De-Cat and Spark Arrester

[xposur]

I decided to mod the exhaust on the Hawk. It is really restrictive and there is not a lot of aftermarket exhaust systems that work for this bike. I know of 2 brands but they do not line up correctly and sit lower than they should.

First Thing I did was remove the spark arrester and cut off the plate in the back of it with a cut off tool and replace it with a screen to improve the flow a little bit.

2nd was the cat.
I removed the header pipe, its bolted to the head (2 14mm nuts) and muffler(10mm bolt clamp).

Once removed I used a cut off tool to cut it directly in the middle of the cat.

The cat was really restrictive and held a lot of heat in the exhaust. To remove the cat material I used a 3/8 drill bit to drilled in the center and worked my way up in size. The metal will twist around the drill bit and pull off the pipe nicely. The key is to go up in drill bit sizes and work around in the pipe and the metal will come out easily. Use needle nose pliers to pull off any remaining metal and or a flathead.

Once the pipe is cleaned out of the cat material, bolt back to the bike and use the heat shield as your alignment guide.

Weld a bead on there so it holds, then remove and finish welding around.

(Welding tip:make sure you use a shallow penetrating rod if your arc welding like me. I was anxious to do this and used whatever rods I had at home, which was a 6011 and this will melt a hole in the pipe! Use a rod like a 7014, or stripe down the pipe to bare metal and use a 6013. I used 6013 which is for clean metal and the exhaust pipe has a coating on it, ended up giving me slag holes. Im not a pro welder either, I can weld, just not pretty!)

After you weld all the way around, check for leaks by putting the welded section in water and blowing into the pipe. Alternatively you can coat it with gas leak solution and look for bubbles after blowing into it. I had a few air leaks on mine so I covered them with JB Weld.

I painted my entire exhaust with a goldish high temp paint from autozone and installed it back on. Will most likely need to go up in jets.

[xposur]

If you have a small grinder dremil, grind down the welds on the inside of the header pipe to improve the flow a little more as the came lousy from the factory.

['16 TT250]

I've never seen a soft cat. like that. The ones I've dealt with were always a hard crumbly honeycomb material, the couple I've gutted I just used a punch & hammer. I wonder if that's a China special or the new way they're made.

[Azhule]

What kind of Exhaust Header Gasket was used on your HAWK?

Did it come with a good 'copper crush gasket' (right in pic) or was it similar to what I had as my header gasket (Bashan WILL)... it looked as if they used a piece of soda can metal cut like a coil/spring and smashed down to 'make a gasket' (left in pic)



I replaced that crap with a Honda OE part # 18291-MN5-650 to fix my "gasket" problem

[xposur]

There acaully was no gasket lol, atleast non that I saw taking off. Here is a pic of it painted and on the bike

[pcspecialist]

I'm still trying to locate a source for a new header pipe as I don't want to mess with the existing one. I have the latest version with a flange instead of being slip over. All requests to Q9 and to Adam Rinkleff have gone unanswered.

The current exhaust system version has a much longer spark arrester and I doubt any mods to it would make any improvement. I think getting rid of the cat is the only thing that will.

[Weldangrind]

Thanks for the pics and write-up.


I haven't been successful in removing cat material with a drill bit. One of the best tips I've read on this forum was to cut a window in the header (basically half of the tube material, or a little more), pop the cat out and weld the window back in. You don't lose the alignment that way. BTW, a decent MIG will make you smile on jobs like this.

[xposur]

Originally Posted by Weldangrind

Thanks for the pics and write-up.


I haven't been successful in removing cat material with a drill bit. One of the best tips I've read on this forum was to cut a window in the header (basically half of the tube material, or a little more), pop the cat out and weld the window back in. You don't lose the alignment that way. BTW, a decent MIG will make you smile on jobs like this.

Yea I didnt think of that..does sound a lot better. Yea Im planning on buying a mig welder, the flux mig from harbor freight (I want to get that plasma cutter too!) but I haven't been doing that many weld jobs to get one so I borrow the Arc welder here and there. Is it a lot easier to weld with the wire feed as opposed to stick welding?

[BlackBike]

Originally Posted by xposur

Yea I didnt think of that..does sound a lot better. Yea Im planning on buying a mig welder, the flux mig from harbor freight (I want to get that plasma cutter too!) but I haven't been doing that many weld jobs to get one so I borrow the Arc welder here and there. Is it a lot easier to weld with the wire feed as opposed to stick welding?

I love my Lincoln Flux core wire welder. So easy, even i can weld. point and shoot hot molten steel

Great job on the pipe, just get er done.

P.s. that screen will coke up and will clog eventually but if maintained should not be a problem.

[xposur]

Originally Posted by BlackBike

I love my Lincoln Flux core wire welder. So easy, even i can weld. point and shoot hot molten steel

Great job on the pipe, just get er done.

P.s. that screen will coke up and will clog eventually but if maintained should not be a problem.

Knowing that makes me want to buy a flux welder even more! How are they for deeper penetrating welds?? I know with rods you have ones for shallow penetration and other rods for medium to deep penetration

Yea i figured, I will clean it every year or so..I just want to stay legal for national forest riding.

[BlackBike]

I think the pic should tell you alot. This is from inside of the weld door and is quick for material reference. They are great for what they were intended for,which 90% of the time is perfect unless you are a BBQ fab guy or pipeline welder (haha). It will do that too just mabey with a couple of passes. It cost around $500 @ home depot 10 years ago but decided it was one of those good long term investments. Fixed trailers, garage doors, strength equipment, BBQ pits, road graders. Used infrequently but always have it when needed. Most reciently, Chinese motorcycle ha.

[Weldangrind]

Originally Posted by xposur

Is it a lot easier to weld with the wire feed as opposed to stick welding?

You wouldn't believe how easy; point and shoot. Arc welding is an art on a couple of levels, because you not only scratch-start, but the rod is being consumed as you move, which moves your hand closer to the work as you travel (as you well know). Wire feed can be held at a constant distance from the work and it will easily weld out of position.

I recommend against flux core only. Get a true MIG that will accept shielding gas and then the choice is yours, in terms of using gas or flux core. I also recommend a welder with infinite voltage control, rather than four, five or six settings. My voltage control goes from 1-10, and I spend most of my time between either 2-3 or 3-4 on the dial. the finite control is very useful, whereas limited controls might either not give the penetration you need or might burn right through (which is quite frustrating).

I bought a Miller 175 about 10 years ago, but since then, Eastwood has come out with a decent MIG welder that has infinite voltage control for cheap. If you want a 120VAC machine, check out http://www.eastwood.com/mig-welder-1...5a-output.html The price is certainly right. I have a friend with that welder, and I like it just fine for small jobs. It uses Tweco consumables, so parts are easy to find.

[rojo_grande]

I got the cheap HF 90 amp welder a number of years ago to weld in some patch panels on a vw bug project but only after lots of practice with different settings etc. Also switched to different/better wire than the HF stuff. http://www.amazon.com/BA71TGS-030-In...e+welding+wire

Much better results, less spatter.

Rojo

[Weldangrind]

Originally Posted by rojo_grande

I got the cheap HF 90 amp welder a number of years ago to weld in some patch panels on a vw bug project but only after lots of practice with different settings etc. Also switched to different/better wire than the HF stuff. http://www.amazon.com/BA71TGS-030-In...e+welding+wire

Much better results, less spatter.

Rojo

I used a spiffy little 120VAC Cebora (Italian) MIG welder to build my first utility trailer, about 15 years ago. The duty cycle was pathetic, so I installed a fan and drilled a bunch of holes in the rear cover so it could breathe. I then installed a better quality ground cable and clamp, to replace the shoestring that came from the factory. Both mods helped to increase the duty cycle dramatically, but it would still sputter and fail under heavy use.

It was only useful within a small range of metal thickness, so I set my sights on a Miller; haven't looked back since.

[dpl096]

Originally Posted by Weldangrind

I used a spiffy little 120VAC Cebora (Italian) MIG welder to build my first utility trailer, about 15 years ago. The duty cycle was pathetic, so I installed a fan and drilled a bunch of holes in the rear cover so it could breathe. I then installed a better quality ground cable and clamp, to replace the shoestring that came from the factory. Both mods helped to increase the duty cycle dramatically, but it would still sputter and fail under heavy use.

It was only useful within a small range of metal thickness, so I set my sights on a Miller; haven't looked back since.

If I'm doing any serious welding with my little Handler 110 I open the side panel and set my garage pedestal fan there blowing on it. That greatly increased the cycle ... I still think these small flux welders are the berries. Plus they keep getting cheaper and now with a good review below on a unit from HF there's little reason for a hobbyist not to treat themselves to one.