[Guest]

Some of the work done to my stock header:
Removal of precatalyst in header.
Head flanges port matched to head, then sides and bottom opened 0.025 inch to reduce reversion.
Inside casting and welding flash removed.
Ceramic coated with Techline Coatings Satin Black - 2 coats.
Wrapped primaries to below oil cooler with Thermo Tec copper impregnated 'glass wrap.

Precatalyst removed:

Header wraped and coated:

 

[Guest]

Compared to a friends bike with the same exhaust, the exhaust sound is noticeably deeper and louder with these mods. Not a lot, but it is obvious.

Also, I used high temp BBQ grill paint to cover the copper colored header wrap.

 

[Guest]

Hey dev, I seem to remember a post from you on how you did the preCat removal.
Could you give us old people ( okay--that is just me ) a quick refresher( if you got the time---Thanks TRACKER)

 

[Guest]

The following is a brief overview of how to remove the precatalyst in the 1050 header:

The pre-cat is a simple tube that is coated with a catalyst coating. It is held in place with two outter rings that have locating pins welded through the header pipe after the collector. The front pins are welded through the header with spot welds in front of the rear header mount (top and bottom). The rear pins are located through the header flange weld near the header outlet (top and bottom as well). There are 4 locating pins welded in place in total.

1.) Drill out front spot welds top and bottom with 3/8 inch bit.
2.) Cut rear pins from inside with air (pneumatic) or hand chisel.
3.) precatalyst should slide right out.
4.) Weld up holes from spot welds.
5.) Use 6 inch long carbide burr and sanding rolls in a die grinder to remove remains of locating pins and welding slag. A Dynafile also helps.

Total time to remove and weld back up took about 30 minutes - easy.

Flange work:
Using a die grinder with carbide cutter, burr, and sanding rolls.
Widen each flange where it meets the head's exhaust ports.
Clean up the top of each flange.
Cut bottom of flange to provide 0.025 inch step - to not compromise sealing.

Detailed photos are in the Gallery in "Motorcycle Related" section.

I hope this helps.

 

[Guest]

Thanks Dev. One other question: is there "special" welding necessary to fill the holes in the stainless??

 

[Guest]

Well, I'm kind of "short bus" special....

But no, nothing special other than matching the rod to the header material.

 

[kuhlka]

If you want to do an exceptional job on stainless you'll want to use TIG/GTAW and some backing gas that'll flow through the tube to keep the backside from losing it's stainless properties. If stainless overheats it'll burn out the chromium and/or nickel.

 

[Guest]

I use TIG and don't find a reason to back gas when welding stainless tube (or Ti) - even though I have the ability.

 

[Avi8or]

Won't Ti go brittle if welded and inert gas isn't used?

 

[kuhlka]

Well, it oxidizes at a relatively low temperature compared to steel. Hobart Welding Institute, where I went to school for QC-7 welding classes and certs, recommend always using backing gas on stainless or titanium unless its just a practice piece. I'd be wary of buying someone's exhaust system if it wasn't backpurged when welded. Your pretty $1k+ system will just rust from the inside out like regular galvanized steel once it has lost its stainless properties. Just look at my brown mid-pipe, lol. I welded some elbows together in a quick job to fit an 02 Daytona 955i CF can without gas and it turned the nice stainless gray then it rusted brown after it was on the bike for a few months. I'm going to eventually get the headers and exhaust coated black though so no biggie. When I make a header for my bike, I'm going to definitely purge it.

 

[Guest]

Thanks guys, I'll see if i can get some one local although asking someone about purging and back gas sounds like something the Cheapest would do!! ;D

 

[HarriS]

Root gas is absolutely obligatory with titanium and very highly recommended with stainless. The pieces may stay together but the seam does not meed any certificates for sure.

 

[Guest]

This isn't going to be popular:
I back gas when building structural parts like tubular frames and cages. I even have an enclosure for welding specialized parts in an inert gas atmosphere.

For exhaust systems, I purge them and rarely back gas. Are they certified, no. Do they work well? Yes. I know several marine exhaust manufacturers do the same on twin wall water cooled exhaust systems.

I have several headers in stainless and one in Ti that were not back gassed and have no issues with oxidization, even after several years of use. One of them is on a rotary engine with 28 psi of boost and very high exhaust gas temps for several tears. It looks and works great to this day.

I have had to weld up one set of Acropovic Ti headers due to cracks. I welded them by simply purging them with gas and then welding from the exterior. The welds held fine.

I have built several stainless tuned pipes for two-strokes that see very high EGT's and still have no issues with oxidization in the welds - no back gassing was used to construct them.

Are any of these parts x-rayed or distructive tested? No.
Are any of them certified welds? No.
Do they work well and last? Yes

Is back gassing a good idea? YES. Is it always mandatory? NO.

How many aftermarket exhaust manufacturers (cycle, auto, or boat) do you think perform destructive testing on their welds?

 

[racecomp]

The only time that you have rusting of stainless welds with tig welding is when the Tig operator is to slow, If the metal gets hot for to long it will eventually go rusty because the burn out of the chromium or it’s poor quality to start with.

Best welds are often done a few hours into the job, if you’re not welding every day you will be out of touch for a few welds.

Purging your weld is the best way to go, but it’s expensive. This is one of my stainless turbo manifolds for the 1050 It has not been purged! It will not go rusty I’ll guarantee that!!!!!

If you are after the very best quality welds then purge away but your welds will only be as good as the kit that you are using and the ability of the operator.

For most of us now and again welders it’s practice that makes the job good!!!!

http://www.triumphrat.net/albums/album441/abm.jpg

http://www.triumphrat.net/albums/album441/abn.jpg

 

[racecomp]

And a few more pictures that got lost last week.......

 

[racecomp]

One more thing, you could weld with a blindfold on and still do a better than the OEM mig welded Triumph headers!!!! They are poor; I have two sets of headers that leak the obligatory black condensation water from the collector box on my Daytona motors on start up………

 

[kuhlka]

Yeah, I'm not saying exhausts have to have backing gas, just a low cfm purge to prevent air from oxidizing the weld from the backside while you're welding (which makes TIG a PITA). If all your joints are perfect and have no gaps whatsoever and you're welding very quickly, you could probably get away with no purge. The welds are going to hold regardless unless you're the world's suckiest welder. Yep, overheating the piece is indeed what causes burnout of the chromium/nickel.

 

[briank]

o.k. i removed that pesky precat. it is getting welded and ceramic coated over the weekend. do you have a decent internet source for the exhaust wrap? how is it held in place on the pipe?..........

 

[Guest]

Brian,
Lots of sources for header wrap - try www.jegs.com or www.summitracing.com - Many Advance Auto Parts shops carry header wrap kits in stock.

I used Thermo Tec brand, but there are many available and most are simple fiberglass cloth. Black wrap is available, but you can also use high temp paint (or BBQ paint) to coat the wrap after installing it.

You want to use 1 inch wide tape. It is easier to wrap around the small primary pipes without gaps.

Some kits come with bands to hold the wrap in place. Some kits require you buy seperate bands.

 

[briank]

devious....
i was scouring the inernet for wraps and came across this article. what do you think of it??? thanks


http://www.centuryperformance.com/heatwraps.asp