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Author Topic: Chrome going brown  (Read 2901 times)

SimonT

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Chrome going brown
« on: April 10, 2011, 09:39:11 PM »
Hey Guys

The chrome on my exhaust is going a goldy brown colour. Just wondering what is causing it, and how do i remove it?

Ducati Scotty

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Re: Chrome going brown
« Reply #1 on: April 10, 2011, 10:58:27 PM »
When chrome gets hot it tends to discolor.  I've heard that it's the impurities in the metal pushing out.  I think it's really just oxidation.

I see this in two main spots on the new bikes: right near the head and about 3/4 back on the lower part of the muffler.  The stock pipe probably has pretty good back pressure because of the catalytic converter, it's both an inherent restriction and needs to be hot to work.  This causes the hot gases to be held in and really raise the temp in spots.  Near the head is as hot as it gets.  I suspect that the part of the muffler that turns color is either a constriction (the catalytic converter) or an internal bend that reverses the gas's direction.

You can use metal polish and a lot of elbow grease, this will often take care of it or at least minimize it.  In the long run it will come back.  Your best bet is to get an aftermarket muffler without a catalytic converter.  This allows the gases to flow out more easily and lowers the overall temperature.

Hope this helps,

Scott


SimonT

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Re: Chrome going brown
« Reply #2 on: April 10, 2011, 11:07:46 PM »
you were spot on with your locations....

a bit near the engine... and the other bit formed a bit of a band around the muffler.

That sux if its going to keep coming back :( it appeared after my first highway stint. So im guessing it was the higher RMP for a longer period of time.

So... what pipe should i look at getting? :)

singhg5

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Re: Chrome going brown
« Reply #3 on: April 10, 2011, 11:31:26 PM »
That sux if its going to keep coming back .....So... what pipe should i look at getting? :)

Simon:  

The golden / brown color on the pipe is a sign that you have been riding the bike well !  The pipes last many miles, even with the color.  In my opinion there is no need to spend money on getting a new pipe unless the performance is affected. Just look at the scenery when riding the bike :D. and spend the money on Fosters lager and some good food.
« Last Edit: April 10, 2011, 11:53:32 PM by singhg5 »
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GreenMachine

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Re: Chrome going brown
« Reply #4 on: April 11, 2011, 12:00:15 AM »
exactly..i'll be dam if i'm gonna try to get that brown n blue spot on my header pipe cleaned off....life 2 short to give a shit about that...a foster be good right around now...haven't had 1 of them in a long time mate.. ;D
Oh Magoo you done it again

SimonT

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Re: Chrome going brown
« Reply #5 on: April 11, 2011, 12:15:28 AM »
im not too worried about the one on the header... but the one on the muffler looks gross hehe...

Btw... Fosters = gross ;) They dont even really sell it here in Australia.

There are plenty of other local beers which are actually drinkable  ;)

bob bezin

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Re: Chrome going brown
« Reply #6 on: April 11, 2011, 12:22:44 AM »
the discoloration is normal. usually the pipes on most bilkes turn blue eventyually. don't worry enjoy the ride.the pipes on my 04 triumph are almost black due to the restrictons in the mufflers. my enfield pipes are getting blue . no big deal.
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GreenMachine

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Re: Chrome going brown
« Reply #7 on: April 11, 2011, 12:45:57 AM »
actually i haven't had a fosters for a few years...guess i won't get it then...plenty of local  microbeers to get my hands on....keep polishing that pipe joint.. ;D
Oh Magoo you done it again

Ducati Scotty

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Re: Chrome going brown
« Reply #8 on: April 11, 2011, 01:23:51 AM »
I'd say what's been said: ride and don't worry.  If you really can't stand the discoloration there are two period appropriate style pipes available:
http://nfieldgear.com/enfield-store/aftermarket-parts-accessories/exhaust/efi-silencer.html
There's also an upswept model but you can only get that through the dealer.  They're both a little louder than stock and give a modest performance improvement over stock according to reports here on this forum.  The upswept is the louder of the two.

Also, we have a 1 3/4" head pipe.  This is the same size as most modern Harleys.  So there are plenty of aftermarket options out there that you can use so long as you can get or make a bracket to support it.

Scott

Chris-G5

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Re: Chrome going brown
« Reply #9 on: April 11, 2011, 03:41:20 AM »
The best stuff for removing discoloration on chrome pipes is Blue Job. It takes some work by hand or you can use an orbital sander like in this video.

http://www.youtube.com/watch?v=BWaChZa5htg

Here is an inexpensive silencer that I have on my G5. You can't beat the price even if the shipping is the same as the $37.99 price. It's like the "EFI silencer" from nfield gear.
The inner diameter is 1 3/4" and the head pipe has an outer diameter of 1 5/8" So you'll need a short pipe to insert into the silencer to reduce the inner diameter to 1 5/8". I got a 4" pipe form the auto parts store that worked perfect.

http://cgi.ebay.com/ebaymotors/CHROME-ROYAL-ENFIELD-500cc-ELECTRA-SILENCER-ASSLY-NEW-_W0QQcmdZViewItemQQhashZitem1e62c467c9QQitemZ130506057673QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_6544wt_1167
« Last Edit: April 11, 2011, 03:51:47 AM by Chris-G5 »

REpozer

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Re: Chrome going brown
« Reply #10 on: April 11, 2011, 04:32:01 AM »
Hmm, guess mine never gets hot enough to discolor.
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GreenMachine

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Re: Chrome going brown
« Reply #11 on: April 11, 2011, 03:06:14 PM »
I remember when the bike was new and breaking it in (winter) that OEM header pipe would get blue and purple and hot as  the dickens.  Got a new exhaust system, re jetted and she just has that golden brown look 4 " above the neck ,no browning at the muffler joint....
In retrospect I probably should have coated the header pipe when I brought it new as
the coating hardens overnight  and supposedly acts like a insulator and cuts down on the heat transfer to the pipe.  U can't coat the inside of a used pipe ...rambling thoughts for the morning chat.
Oh Magoo you done it again

REpozer

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Re: Chrome going brown
« Reply #12 on: April 11, 2011, 03:42:54 PM »
Coated with what?
2008 AVL Classic Bullet in British Racing Green
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GreenMachine

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Re: Chrome going brown
« Reply #13 on: April 11, 2011, 04:10:25 PM »

google exhaust coating and take your pick..external or internal...if i ever order a new complete exhaust system for the enfield, I would consider doing this to see if their is any improvement on look and performance...It could be voodoo science too...and cost would be a factor..Guess u could Kreeme a new exhaust and c what that does for u..U know that blue crap in a bottle for 30 bucks....has to be for a new virgin pipe and let it cure for a day or two...

“Internal Exhaust Coating”
For protecting chrome pipes or for those wishing to impart the maximum thermal barrier properties, and obtain a smother interior surface for enhanced exhaust flow.

A ceramic based coating used as an internal lining to achieve maximum insulating properties between exhaust gases and the metal surface. The greatest benefit is realized at the area where the exhaust hits the first bend in the pipe, however a complete lining will result in maximum benefit. Great for exhaust ports. Pipes must be new to be guaranteed.

Minimize or in most cases eliminate chrome pipe bluing
Obtain maximum thermal barrier properties
Improve exhaust gas velocity, increase hp.
Our coating service includes all necessary preparation for coating adhesion.

Pricing upon request
Oh Magoo you done it again

Ducati Scotty

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Re: Chrome going brown
« Reply #14 on: April 11, 2011, 05:04:12 PM »
Three cans of flat black Krylon and you won't care what the shiny bits look like.  Sometimes I miss the complete lack of needing to ever wash your bike when you own a Dark Ducati.

Scott