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BLACK BELT
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Discussion Starter #1,041
Not that I own anything special, but it's hard to believe that mild steel would be the go-to material for pipes of that caliber. I mean, who would drop a grand or two on custom pipes just to watch them rust away. Sure, you could ceramic coat the inside, but it still seems odd. $0.02
Well, pound for pound, BT pipes are probably the most expensive. As they should be. BT's history is building race pipes for the fastest bikes on earth. And he's been very sucessful.

The reason for mild steel pipes is because they're the best for racing. Titanium pipes are lighter, but they don't last. I'm guessing stainless pipes were never a part of BT's repertoire.

So, what do I do? Send him an email asking him to make stainless pipes.
Good job. :D
 

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V four honda whore
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only one way to find out if he will do it :) but you could try what Julian suggested. knowing that you are asking for an exception. would be better if you would ask that in person
 

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Race pipes are only expected to last a season, too, and race machines get torn down/rebuilt every meeting at least so I doubt rust is an issue during the useful lifetime of the pipes.

My dad used to make 2-stroke pipes for racing and his were also always mild steel. Some race guys have a palpable contempt for anything that's more visual/aesthetic than performance/function over form, especially guys from that era.
 

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V four honda whore
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Corect me if im wrong, but arent stainless a bit lighter?
 

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BLACK BELT
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Discussion Starter #1,045
Corect me if im wrong, but arent stainless a bit lighter?
Nope. That's the problem. Stainless is heavier than mild steel.

Another issue is the metallurgy. I'm pretty sure mild steel pipes make slightly more power due to the properties of the metal. Also pretty sure stainless is more prone to cracking than mild steel.
 

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BLACK BELT
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Discussion Starter #1,048
Cost is probably a major factor, as well.

Stainless pipes cost more because they're more difficult to fabricate. Dosen't make sense for racers to spend the extra money.
 

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V four honda whore
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What about ceramic coating to protect them?
 

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BLACK BELT
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Discussion Starter #1,050
What about ceramic coating to protect them?
Pretty sure ceramic coating reduces power because it changes the way the exhaust gas pulses are reflected. Similar to using different metals and wall thickness.

Helps to prevent rust, but I believe it burns off near the exhaust flanges.

There's also chrome plating, but good chrome will increase weight and affect performance.
 

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forks and valves... WTF?
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671 Posts
SERIOUSLY? I gotta say that anyone who is worried about mild steel pipes rusting on a 2-stroke has never owned a 2 stroke. My first motorcycle was a 2-stroke, my first street bike was a 2-stroke, my first race bike was a 2-stroke... for the past 40 years I've always had 2-strokes and I've never had issues with rust on an expansion chamber.

The proper coating for the outside of the pipe is BBQ paint. It comes in a rattle-can. Its easy and economical to apply. If it get scratched, scrapped, dirty, wears off, or whatever, its super easy to re-apply and make the pipe look new again. As for the inside of the pipe... well if you don't know whats happening there you've never owned a 2-stroke, but lets just say a 2-stroke pipe will never ever rust from the inside (if the bike is being ridden).

Guys like me were originally attracted to 2-stroke motorcycles because they are simple, relatively inexpensive, and easy to maintain... so mild steel chambers fit this scenario. I understand that Smoker wants this to be a very nice looking show bike. I get it. I have nice show bikes too... and they look fine with BBQ paint on the chambers...

:fu:

[/url]20150501_202647 by andbike, on Flickr[/IMG]
 

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BLACK BELT
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Discussion Starter #1,052
Well, I've definitely had to deal with rust on my two-stroke pipes.

Guess it comes from outside storage and rain riding, but rust isn't a concern with this bike.


There's nothing custom about black painted mild steel pipes. Even stainless pipes are nothing special.

This is supposed to be a custom bike. That's why I'm trying to do something different.

Nice show bikes are a matter of opinion.
 

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forks and valves... WTF?
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671 Posts
This is supposed to be a custom bike. That's why I'm trying to do something different.

Nice show bikes are a matter of opinion.
I totally get it... and you have a particular style to your bikes. :thumbsup:

I just had to chime in with my $0.02 :D
 

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BLACK BELT
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6,918 Posts
Discussion Starter #1,054
Stayed up all night drawing the stainless exhaust pipe flanges and silencer caps. Got the drawings to the machine shop on Friday.

When I measured the original Toomey silencer cap, the I.D. was less than .875" which is the I.D. of 16ga. 1" O.D. tubing. So, I opened the I.D. of the cap to .875". Also shaved down some areas to lighten the stainless caps.
 

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BLACK BELT
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6,918 Posts
Discussion Starter #1,055
Stainless exhaust flanges. Go between the pipes and silencers.



I used the pipes I have at home to determine the flange thickness.

(After the parts are made) I realized that other pipe flanges support the weight of the silencers. But, my silencers are bolted to the subframe.

So, I'm going to send the flanges back to the machine shop, and reduce the thickness from 0.100" to 0.0625"
 

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BLACK BELT
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6,918 Posts
Discussion Starter #1,056
Stainless silencer caps. Go between the silencers and the exhaust tips.



The flange wall needs to be thick to fill the space between the inside o-ring and outside snap-ring/circlip. So, I cut down the flange thickness on the inside, except for the contact area. I left 0.0625 wall thickness, but I should have made it a little less. It's light, but it could be lighter.
 

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BLACK BELT
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Discussion Starter #1,057
Had to have a heart to heart talk with the machinist.

I hate to ask for changes after the parts are cut, but I'm not an engineer or machinist, and I'm just learning as I go.

So, fuck it. Having another 0.0312 inches taken off the silencer cap flanges just to lighten them up a smidge. :rock:
 

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BLACK BELT
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6,918 Posts
Discussion Starter #1,058
Got the silencer caps back.

Machinist ignored my numbers and took off even more material.

All good. They feel light (for stainless).


One of the stainless flanges got bent when the machinist chucked it up. Need to take the stainless bar back to the shop and start over.

If I have to use mild steel pipes, the stainless flanges will be useless.
 

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