Topic: Dealing with rusty pipes

[KingCustomCycles.com]

Try blue job brand pipe cleaner from your friendly HD dealer and a brass wire brush with your steel wool.  If that doesn't bring them around it is paint time.  I like flat black rustoleum high heat BRUSHED on. 

[youngerthanmybike]

Just out of curiosity-  why brush the paint on?

[KingCustomCycles.com]

The spray is far too thin and will burn right off.  I brush it on and then heat cure it with some running.  It will be soft when hot but hardens nicely when it cools, sort of a poor mans powder coat.

[Bill K]

If you decide to paint, I've had good luck with Bill Hirsch Space Age Black aerosol holding up well, cures to a flat black. I've used Hirsch products on my old truck, they make great stuff. I prep my pipes by working them over real good with a BIG wire wheel on my grinder.
                                                                  Good Luck

[katmol]

Ok, here is my wacky idea for the day. I just picked up a used stock exhaust system for my '78 750K. It all looks good on the outside but I'm sure there is stuff going on inside. I can hear little things rolling around inside when I shake them. So here is my thought. Wonder if I could take rust neutralizer, pour it in pipes, slosh it around real good and let it dry for a couple of days before I put the exhaust on. Would it do any good? Any comments on my insanity?

[markjenn]

I don't know, but if I may ask a tangential question on this thread, is there something you can do with good condition pipes to keep them from rusting internally?  I have a CBX with really nice exhaust and it seems sound and I'd like to keep it that way.

- Mark

[aptech77]

I would use ACF50 down the pipe if anything. I use it on my shiny parts etc.... during long winter storage. I use it at work all the time and it is the best. Second best would be Corrosion X.

[GammaFlat]

Adding a little oil to gasoline preserves your pipes.  This was first "learnt" when cars that burned oil never seemed to have failed exhaust systems.  There was a thread on this not too long ago and Terry had some idears on how much oil to add to your gas.  When I install my new HM341s, I'll be adding an ounce or two per fill.  You might foul plugs a bit sooner but new pipes are not cheap. 

[chrislib]

I have used a product called Lawson Rust Converter. Iv`e used it on the frame& the exhaust manifold and turbo housing for my truck (Cummins diesel Dodge). On the frame it has proven indesrtuctible while on the exhaust it held up for about a year or so then started to flake off a bit, but it is still there mostly. Bear in mind the exhaust on my truck can get up to 1200+ deg farenheight. heres a pic of it pre-painted (dont have a current pic, but if dmeand is high i`ll snap one  )


heres a shot of the stuff on the frame rail


does a sohc exhaust get hot enuff to make it fail? who knows, but it couldnt hurt IMO, just keep the drain holes clear.

[katmol]

Hey Chris,
 That's the feedback I was looking for. Is the Lawson Rust Converter a spray on or a liquid. It needs to be thin enough to pour down the header pipe and slosh around the muffler.

I have used a product called Lawson Rust Converter. Iv`e used it on the frame& the exhaust manifold and turbo housing for my truck (Cummins diesel Dodge). On the frame it has proven indesrtuctible while on the exhaust it held up for about a year or so then started to flake off a bit, but it is still there mostly. Bear in mind the exhaust on my truck can get up to 1200+ deg farenheight. heres a pic of it pre-painted (dont have a current pic, but if dmeand is high i`ll snap one  )


heres a shot of the stuff on the frame rail


does a sohc exhaust get hot enuff to make it fail? who knows, but it couldnt hurt IMO, just keep the drain holes clear.

[ieism]

The best thing you can do is prevent short rides in cold weather. Exhausts rust from the inside because watervapour condensates in the pipe. If your pipes are not hot enough after a short ride the water will not evaporate before the bike cools down. And don't leave the bike idling too long before shutting down, give it some proper trottle before shutting it down.

[DORIGTT]

Is is possible to restore the exhaust systems of these CB's if they've only got slight surface rust on them?

[Queeg]

If they are chrome, yes! But it can get expensive to have them rechromed! Some times a soft wheel can be great too, but be carefull not to go thru the chrome. There are a million ways to remove the rust, the trick is bringing the shine back.
Not that I have worked on chrome before. I plane on fixing the hole in my original supersport muffler in january.
When all else fails black paint or a high temp powder coat!

[DORIGTT]

The mufflers come apart to accomplish this right?

[mlinder]

What mufflers are you talking about?
hm300's and hm341's do not come apart.
Neither do the 4 into 4's on the 500's.
Dunno about the f's and the 400's 4 into 1's.

I've had good luck with coke and tinfoil to remove the rust off of chromed surfaces. The main problem is that once it's rusted, that area is exposed to moisture so will rust again. On surfaces that do not get heat, you can use a quick, controlled spray of clear to help protect it from further rust.
Not sure what to do on surfaces like exhaust that gets hot.

[DORIGTT]

1973 CB 750 mufflers

coke and tin foil?

[mystic_1]

Crumble tinfoil into loose ball.  Pour coke on pipes.  Rub with tinfoil.  Phosphoric acid in coke dissolves rust, foil is hard enough to scrub dissolved rust off chrome but soft enough to not scratch the good chrome.  Rinse, polish, done.

mystic_1

[phactory]

Re-chroming an exhaust is a very tricky, not to mention expensive proposition. For one, you cannot do spot chroming. The entire assembly must be stripped and then re-plated. The sheer act of stripping off the old chrome was reduce the part to a rusted mess. I would probably only attempt to do this if the part was NOS and had no signs of rust.

The original exhaust on my K1 has some pinholes that I am going to attempt to fill in with JB Weld and then file and touch up. These holes are all very small, about the size of a pea.

If it is just the surface chrome, then I would clean off the rust and just keep it polished .

Phil

Is is possible to restore the exhaust systems of these CB's if they've only got slight surface rust on them?

[HondaMan]

If it's minor, I've used acetone for thorough cleaning, followed by chrome cleaner and polish. If the chrome starts peeling, spot touchups can sometimes be done with Simichrome, which polishes the metal underneath to a shine. Try to just polish the metal, not the chrome, or you end up with a very bright chrome spot there at the rust site.

[Johnie]

And good luck finding a chromer willing to dip your used mufflers into his tanks.  The carbon destroys the chemical in the tanks and it usually has to be dumped.  Now I have a chromer that will let me know when he is ready to replace his chemicals and then my exhaust is the last to go in.  That is about the only way to get it done.  Unless you find someone that does that chrome spraying I was hearing about...

[DORIGTT]

Wow.  This isn't as simple as I thought. 

I'll try the coke and tinfoil thing and see what happens.

[HondaMan]

Unless you find someone that does that chrome spraying I was hearing about...

...now, you're teasing me...what is this process?

[Jonesy]

Yes do tell.. I've seen the process where they "spray" chrome onto shafts and other surfaces to locally harden the surface, but not for looks...

[blounstation]

So I just picked up a used 4 into 1 pipe for my 78 cb750 and it's kinda haggered but usable. It's already rattle can painted but I'm not sure wait high temp would work to repaint. What's the pros and cons for wrapping vs rattle can?

[KingCustomCycles.com]

Paint is cheaper.