Author Topic: Restoring Exhaust pipes and finned collarpiece  (Read 3132 times)

Offline Charliecharlcomb

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Restoring Exhaust pipes and finned collarpiece
« on: August 10, 2026, 03:46:08 PM »
Now I have opened a can of worms cleaning up some unloved areas of the bike I've decided to remove the exhaust pipes and try to safeguard them for the next 10 years.

They were NOS in 1992, have done 9,000 miles and are generally good but having removed them there are some small rust spots and areas where the chrome has rubbed off. Also one tiny hole where the muffler joins the downtube that could be spot welded as there is no other significant rust.

So, what would be the best way to arrest and protect the chrome from rust?

Also, now that everything else is going to look so nice, what would be the best way to make those finned collars (joint in the spares list) rust free and looking new?

Again, any advice would be welcomed

Cheers


Offline Bryanj

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #1 on: August 10, 2026, 04:46:30 PM »
CAREFULL there is suposed to be a small hole on bottom just into silencer where down pipe is to allow condensation out

Offline Charliecharlcomb

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #2 on: August 10, 2026, 05:06:32 PM »
Thanks Bryan, you are spot on of course. The hole is just along before the breather hole and is probably related. I'll make sure it isn't blocked.

Offline Oddjob

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #3 on: August 10, 2026, 05:57:16 PM »
Very difficult to get the finned clamps looking good. I did a whole thread on just those alone, I think I spent around 20 hours on each one. I still have around 8 still to do. I had some rechromed after doing some smoothing work and some chrome ceramic coated, just to see which lasted longest.

I started with something like these



After a LOT of work, the castings are extremely rough, if you chrome them you leave loads of holes where water gets in, it's this which causes the rust problem. You need to remove all these casting marks, you can see how smooth this is.



One done in chrome ceramic, not polished yet. It's extremely hard and very resistant to road salt etc. I had the collets done in the same stuff so they matched.



And one chromed, you need to get right down the valleys as the chromer can't get in there to polish it, I can but it takes a good while to do.

Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Online McCabe-Thiele (Ted)

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #4 on: August 10, 2026, 06:39:15 PM »
I cleaned my 500 finned front pipe clamps, using Kens plastic wheels, the castings are full of holes, hence why they rust. I settled silver for VHT paint to finish them off.

I have a new set that came with my 500 Delkevic 4 into 4 silencers that I never used, PM me if you are interested in buying them. They are chromed steel,  they look much better than my 500 originals, for complicated reasons I never used them.

« Last Edit: August 10, 2026, 07:19:36 PM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Athame57

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #5 on: August 10, 2026, 06:50:34 PM »
But how did you get it so smooth, anything rotary?
I brake for animals!
1978 CB400F2 named Elen.

Offline Oddjob

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #6 on: August 10, 2026, 07:02:33 PM »
I used a Dremel and some small grinding stones, went through a few. After that those little wheels I keep mentioning, used those to remove the grinding marks and slowly smooth it flat. Finally a modified buffing wheel to get the shine. The chromers did nothing, they were satisfied it was as good as it would ever get. They charged me around £5 each to chrome them. So what I lost in time I made up for in money.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Athame57

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #7 on: August 10, 2026, 11:29:32 PM »
I used a Dremel and some small grinding stones, went through a few. After that those little wheels I keep mentioning, used those to remove the grinding marks and slowly smooth it flat. Finally a modified buffing wheel to get the shine. The chromers did nothing, they were satisfied it was as good as it would ever get. They charged me around £5 each to chrome them. So what I lost in time I made up for in money.
I've never heard of them until now, I think this is now on my bucket list.
I brake for animals!
1978 CB400F2 named Elen.

Offline Oddjob

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #8 on: August 11, 2026, 02:29:44 AM »
I’ll try and post a link up of those little wheels. I try and post links up where they still use the same colours as I started out with. There are 7 colours in total. Some sets use different colours for the same grade abrasive and it can be confusing if we ain’t all singing off the same hymn sheets. The grades are 80 grit, which is dark green, then 120 grit, dark blue, 220 grit, I say red others say brown, 400 grit, light blue, 600 grit, purple or lilac, 1000 grit, light green and finally 2500 grit, white.

The white is like a pumice stone, ok for very soft metals like gold but not great on alloy but you’ll find a use for them. Dark green is very aggressive and is great at getting rust of parts or cleaning up really scabby alloy.

Bristles go in direction of rotation, 2 on a mandrel works well. Don’t press hard, a light touch is best. I’ve used them to clean stainless steel pans for the wife, polished jewelry with them. The uses are limited to your imagination.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Spitfire

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #9 on: August 11, 2026, 09:10:20 AM »
Strangely enough I came across a lot of multi coloured polishing wheels while tidying my shelf, I vaguely remembered them but could not remember where from so thank you for the last post reminding me which was which.
Those pipe clamps look great, I can remember buying a new one (OEM) for my F1 and when it arrived it was nearly as rough as the one I was replacing, so mine got a coat of high temp aluminium paint in the end.

Cheers

Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Online McCabe-Thiele (Ted)

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #10 on: August 11, 2026, 09:21:24 AM »
I agree 100% with Ken, those plastic wheels are fantastic.
A couple of years ago I dropped a teaspoon in our our sink waste disposal unit.
When I recovered the spoon that was part of a set, it was all chewed on the back of the spoon end.

Last year I decided to try and dull the sharp edges and clean up the spoon using 80 grit to remove the deep marks, then 400, then finished off with 1000 wheels. Now out of the set it takes me a while to find that spoon, it has turned out that good. If I get bored I might try to improve it even more one day.
« Last Edit: August 11, 2026, 07:19:58 PM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Charliecharlcomb

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #11 on: September 04, 2026, 03:48:59 PM »
I went for the David Silver pattern parts in the end. It looked like way too much work to bring back the originals and I’m happy with what they have sent. Worked out around £20 each including postage.

Offline Oddjob

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Re: Restoring Exhaust pipes and finned collarpiece
« Reply #12 on: September 04, 2026, 04:34:13 PM »
They look better cast than the originals. As you spot the only parts the chromer could polish was the edges of the fins and the holes for the studs. Not as rough as the originals so hopefully they’ll last longer. Watch the bottom of the valleys between the fins, the rust will appear there first.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.