850 Commando rear mudguard/fender stainless or chrome??

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998cc

998cc

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Hello All.
I pulled my rear fender; it has a few dents and a lot of scratches. Looking closely at few areas around the mounting/fixing bolts where these have galled/rubbed the finish, no copper plating is found. I found this thread relating to a '72 Commando.

What rear fenders / mudguards do I have?

Hi, I have searched the forum but not found the answer to my query. I have a 72 Roadster (204xxx Combat) and have two rear mudguards available but don't know which is correct. Both are magnetic although one looks stainless. Both have the same profile and drillings and the cut-out for the...
www.accessnorton.com www.accessnorton.com

My fender is magnetic and has a "Made in England" sticker applied. Is it stainless or chrome?? If stainless, I'll hammer it out and polish it. :)

850 Commando
Manufactured 9/73

Thanks and best regards,
~998cc
 
I don't know about your Commando but the MKIII is Stainless - mildly magnetic.
 
my 74 Mk2's fenders or mud guards are definitely stainless. had a few dings and dents in them when I bought the bike, and used old school hammer and dolly to straighten things out. took them to my buffing wheel and with a little green rouge, they shined up like new.

BTW, some types of stainless are mildly magnetic. I do know that 18-8 stainless is mildly magnetic.
 
Both my 72 750 and a friends 74 850 (307*** are stainless. Both originally had the made in england transfer on the fender, I'd go with stainless.
 
My '74 850 mk II was definitely chrome and rusted like a retired whore..... same with the front.
 
Both the front and rear fenders on my 73 850 MK1 are stainless
 
Thanks folks! Absolutely no rust on this one, so I am betting it's stainless.

Regards,
~998cc
 
Stainless fenders were introduced sometime in the '72 (MkIV) model run. I believe on the Interstate only at first. Everything from '73 on should have had stainless fenders. If your 850 has rusted fenders it may be due to the alloy used as the stainless fenders are magnetic as well.
 
My 1974 Roadster featured Corrosion Resistant Steel (Stainless is such a misnomer) fenders. I was able to polish out most of the pitting on my front fender but the rear pitting was beyond help. Replaced with another CRES fender.
 
I've worked a lot of SS alloys in my years and I'd be ashamed to call what I have SS..... It really doesn't behave anywhere near like the stuff. SS generally weeps & bleeds while this went right into blistering and deep pitting while in storage. Had to polish it weekly when I rode it because it would begin to weep.
Anyway hope you guys got better.
 
jbruney said:
I've worked a lot of SS alloys in my years and I'd be ashamed to call what I have SS..... It really doesn't behave anywhere near like the stuff. SS generally weeps & bleeds while this went right into blistering and deep pitting while in storage. Had to polish it weekly when I rode it because it would begin to weep.
Anyway hope you guys got better.
Click to expand...

jbruney. Please clarify "weeps and bleeds". Is this a result of working the metal itself or something else?
(edited)

Thanks.
998cc
 
'Weep & Bleed' is common enough in that there is iron in the alloy and it does tend to weather through. You see it quite often in the petro/chemical plants over a period of time, but as a rule there is no pitting or blistering in the grades used. Then to add into this mix there are more grades/types of 'stainless steels' than I can count also, so there is no way to know which was used in the creation of these mudguards. So to close my opinion I have to state that; They've not rusted through, although had to be painted leaving them still useful for possibly another 46 years, so the term 'resistant' fits the material so much better.
 
My 74 was stainless (resistant?) and I had them chromed 40 years ago. Much easier to keep shiny.
 
Just a note on my use of the term "Corrosions Resistant". In the late 1970's I worked as an Engineer in the aerospace industry. In almost all cases that called for "stainless steel" whether 316, 304 and some of the monels the prints (pre-CAD) were marked as CRES -Corrosion Resistant Steel along with the grade.

Look underneath a vehicle manufactured in the last 20 years or so. The exhaust will usually be a copper-hued color with some surface pitting. In most cases the pipes will be 304L (low carbon for improved welding) while the stamped mufflers may be 409 or 420. These are all "stainless" alloys but show pitting and discoloration. The good news is that they will easily go 100,000 miles and numerous grit / salt exposure on the proving grounds.

Discussion on the use of "SS" for Norton applications is interesting - I am always very hesitant to use "SS" unless I know the grade and the material characteristics and treatments.

Nuff said - good for future discussions.
 
It really doesn't belong in here anyway because to we laymen it can become mind boggling leading to head 'splos;)ions', and I want to keep my near empty unused one in one piece for wifey to sell in a garage sale when I die.
 
In the island life we live in Auckland, the Tasman Sea is 45min drive to the West and the Pacific is 15min to the East. Salt air is everywhere. 316 is the grade of choice for me. My original '74 stainless mud guards have held up fine.
 
Last edited:
Ron L said:
Stainless fenders were introduced sometime in the '72 (MkIV) model run. I believe on the Interstate only at first. Everything from '73 on should have had stainless fenders. If your 850 has rusted fenders it may be due to the alloy used as the stainless fenders are magnetic as well.
Click to expand...
Hi Ron,
Very likely what you say about introduction of stainless fenders in production. What is the source of this info? My ‘73 750 220627 had stainless. I recall it was Nov 1972 build on the ID plate.
 
My "74 850 has a chromed front and stainless rear. I believe front chrome done during a restoration effort in the '90s, when the engine side covers (primary and timing), gearbox outer and rocker covers were all chromed. The mudguard has not held up well and is flaking around the rivet points. So much so I plan to replace it with nice used stainless front I collected for peanuts. It will then match the rear.
 
When I chromed my front mudguard I drilled out the rivets and had the bracket chromed separately. The stays too.
 
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