1973 850 Commando front brake M/C question

NickZ said:
I have a MC that has not been sleeved that has a similar marking.
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Hey, like I said earlier, pardon the newbie ignorance! :)
marshg246 said:
Call me a contrarian - go ahead, I am :)

I would never sleeve a standard Norton M/C. I would never knowingly ride a Norton with a sleeved M/C. I would never replace a working standard Norton M/C just to have a 13mm version. If I needed a new Norton M/C I would buy the 13mm version.

Why? Too many stories of sleeve problems and stopping only has to do with the pressure placed on the P.O.S. caliper pistons and therefore pads. The standard and 13mm M/C can both produce the same pressure but the 13mm requires less grip strength - that's their value. Of course, if you don't have the grip strength, then that would be a reason to change.

Yes, I have ridden Nortons with both and they all stop just as poorly :)
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While I think it would be a blast to spend a huge sum of money improving a Norton Commando beyond its factory configurations, I won't be doing that at nearly 65 years of age. Where I ride and how I ride, as well as limited funds, leave me out of that game. I currently own 4 vintage Brit bikes and never get too attached to any of them. I mostly go for original paint survivors, ( the Norton has been repainted) but I am not afraid to sell em or trade em like baseball cards.So as far as my Commando goes, I'll be buying Andover Norton parts and enjoying this great hobby hopefully without breaking the bank. Fun to have my thread take off into some educational discussions!
Cheers!
1973 850 Commando front brake M/C question
 
Is there an aftermarket fork slider which enables the second disc to be fitted ? I do not ride on public roads, but a single disc is not enough to properly stop a bike of the weight of a Commando when in full flight, and drum brakes are just a bad joke.
I can understand people believing motorcycle manufacturers must know what they are doing when they design motorcycles, but perhaps sometimes they do not. What was considered 'safe' in 1960, might not be now. We used pudding-basin helmets, and drum brakes for road racing. These days speeds are much higher and more people survive.
 
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MexicoMike said:
The two sleeved MCs that failed on my Commando were both from a company that was recommended on various Norton Forums. Their comment after the second failure was, "Wow, two failed? That shouldn't happen!" Really, ya think?
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This sounds like miles enginering.
 
L.A.B. said:
www.rgmnorton.co.uk

MASTER CYLINDER RELINE KIT WITH INSTRUCTIONS FOR ALL COMMANDOS

RGM NORTON 050136 MASTER CYLINDER RELINE KIT
www.rgmnorton.co.uk



I thought they had stopped doing the conversions.
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Don't know - just going by their published instructions. It's interesting that the instructions say kit 875 is DIY and 874 is them doing it. In RGM terms that should have meant 050875 for the DIY kit but you found 050136 as the DIY kit.

Also, 050136 is out of stock. The have lots of parts but apparently not enough to make kits.

1973 850 Commando front brake M/C question
 
marshg246 said:
Don't know - just going by their published instructions. It's interesting that the instructions say kit 875 is DIY and 874 is them doing it. In RGM terms that should have meant 050875 for the DIY kit but you found 050136 as the DIY kit.

Also, 050136 is out of stock. The have lots of parts but apparently not enough to make kits.

View attachment 116671
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My understanding is that RGM just sell kits and don't do conversions anymore but have not updated their documentation. They also sell or loan the special tools needed to do the conversion. They are very clear that it is not a simple operation.
 
The RGM kit was sold way before AN decided to wake up and make a 13mm bore MC. I have used one for over 10 years with no issue.
They do need accurate machining steps and a 18-1.5mm tap and a drill for this tap hole size.
If you have to invest in these items to retrofit your existing MC or you don't have access to a milling machine, then it might be better to purchase the AN kit.
I believe that they sell a housing only where you can transfer your old existing parts to the new 13mm casting. What ever you choose the 13mm bore is much better than the 5/8" bore of the original. The 5/8th... It was like squeezing two blocks of wood together to get the front brake to stop the bike. Very dangerous in today's traffic with ABS brakes and disks all around for 4 wheel vehicles. This isn't the 1970s anymore Toto!

here is the full kit:
andover-norton.co.uk

Andover Norton - FRONT MASTER CYLINDER ASSY C/W LEVER (Pre850MK3) (13mm bore) - 06.4871/13

FRONT MASTER CYLINDER ASSY C/W LEVER (Pre850MK3) (13mm bore)
andover-norton.co.uk
I couldn't find the bare kit which you use your existing parts.

edit:
found it here:
andover-norton.co.uk

Andover Norton - FRONT MASTER CYLINDER ASSEMBLY (PRE-850 Mk3)(13MM BORE) - 06.1939/13

FRONT MASTER CYLINDER ASSEMBLY (PRE-850 Mk3)(13MM BORE)
andover-norton.co.uk
 
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I don't really understand the FS sleeved cylinder, it was posted on FB the other week.

$325 with an exchange core or $410 without a core, that is a bare master cylinder, the Andover Norton bare 13mm master cylinder is around $325.
Why would anyone buy a sleeved version over a non sleeved version, let alone $85 more expensive without a core.

I am sure the vender means well (They sell AN parts) but that one went full cotrel for me.
#
Edit. I checked AN for current prices.

The 13mm master cylinder with cap and lever. US$386.72 (excluding VAT)
The 13 mm master cylinder bare. US$320.08 (excluding VAT)
 
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Time Warp said:
I don't really understand the FS sleeved cylinder, it was posted on FB the other week.

$325 with an exchange core or $410 without a core, that is a bare master cylinder, the Andover Norton bare 13mm master cylinder is around $325.
Why would anyone buy a sleeved version over a non sleeved version, let alone $85 more expensive without a core.

I am sure the vender means well (They sell AN parts) but that one went full cotrel for me.
#
Edit. I checked AN for current prices.

The 13mm master cylinder with cap and lever. US$386.72 (excluding VAT)
The 13 mm master cylinder bare. US$320.08 (excluding VAT)
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At the current exchange rate the bits for the RGM conversion is $74. Say it costs you $60 to get the sleeve installed properly. That is a significant saving over new.
RGM don't offer the installation service anymore (haven't for about three years now) Personally I,ve done quite a few of them for customers in the last few years. They work very well.
 
Jonez69 said:
My master cylinder has a number engraved on the back. I've seen this on M/Cs already rebuilt for sale on internet searches. So I believe this kit to be one installed and sold as a rebuilt M/C. View attachment 116660View attachment 116661
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Looking at the marks adjacent the O ring on the piston, I think they are there because of a material incompatability between the hard anodised piston and the sleeve material (is it an aluminium alloy?) RGMs early sleeves were of some aluminium alloy (I have one, not on a bike!) and the piston in that M/C shows similar marks. I don't know what date RGM changed the sleeve material to bronze (must be years ago) They must have realised that there was a problem with alloy sleeves ( I don't think the alloy sleeves were hard anodised and probably not in the M/C in the above photo), if they were, they might not have had any problems. The std and small bore 13mm M/C's are hard anodised aluminium alloy, The anodising provides a hard wearing surface to the item. The RGM bronze sleeve is far better than an anodised aluminium sleeve or anodised M/C at resisting wear.
 
dobba99 said:
Looking at the marks adjacent the O ring on the piston, I think they are there because of a material incompatability between the hard anodised piston and the sleeve material (is it an aluminium alloy?) RGMs early sleeves were of some aluminium alloy (I have one, not on a bike!) and the piston in that M/C shows similar marks. I don't know what date RGM changed the sleeve material to bronze (must be years ago) They must have realised that there was a problem with alloy sleeves ( I don't think the alloy sleeves were hard anodised and probably not in the M/C in the above photo), if they were, they might not have had any problems. The std and small bore 13mm M/C's are hard anodised aluminium alloy, The anodising provides a hard wearing surface to the item. The RGM bronze sleeve is far better than an anodised aluminium sleeve or anodised M/C at resisting wear.
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That is the kit used as per post #30 and the reason I asked why someone would pay more for a sleeved MC over a non sleeved of the same bore size.

I know my answer in general and for around the same cost as a bare AN unit. (Excluding machining time)

1973 850 Commando front brake M/C question
 
Time Warp said:
That is the kit used as per post #30 and the reason I asked why someone would pay more for a sleeved MC over a non sleeved of the same bore size.

I know my answer in general and for around the same cost as a bare AN unit. (Excluding machining time)

View attachment 116706
Click to expand...

Can you show us close ups of how the reservoir is connected ?

Got similar, albeit less well executed…
 
marshg246 said:
Why? Too many stories of sleeve problems and stopping only has to do with the pressure placed on the P.O.S. caliper pistons and therefore pads. The standard and 13mm M/C can both produce the same pressure but the 13mm requires less grip strength - that's their value. Of course, if you don't have the grip strength, then that would be a reason to change.
Click to expand...
The above statement is worded poorly. The 13mm M/C (sleeved or otherwise) will produce a higher pressure than the std 5/8" bore M/C given the same input, your right hand! The higher the pressure, the better the braking, with the same input, your right hand.
 
dobba99 said:
The above statement is worded poorly. The 13mm M/C (sleeved or otherwise) will produce a higher pressure than the std 5/8" bore M/C given the same input, your right hand! The higher the pressure, the better the braking, with the same input, your right hand.
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You get better feel and therefore more control over how much brake is applied.
 
dobba99 said:
The above statement is worded poorly. The 13mm M/C (sleeved or otherwise) will produce a higher pressure than the std 5/8" bore M/C given the same input, your right hand! The higher the pressure, the better the braking, with the same input, your right hand.
Click to expand...
Reducing the MC diameter is the same as lengthening the crowbar to open a nailed shut case, the further away from the pivot point the more pressure is applied at the case nail for the same movement of the hand. Take it too far in reducing the diameter and the lever will be pulled back to the hand grip before enough pressure is applied.
 
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kommando said:
Reducing the MC diameter is the same as lengthening the crowbar to open a nailed shut case, the further away from the pivot point the more pressure is applied for the same movement of the hand. Take it too far in reducing the diameter and the lever will be pulled back to the hand grip before enough pressure is applied.
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One of the features of radials, bigger bores to move fluid with adjustable lever ratios. (fulcrums?)
 
Time Warp said:
One of the features of radials, bigger bores to move fluid with adjustable lever ratios. (fulcrums?)
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And the way the Racing AP lever works so you can gain some advantage whilst keeping the 5/8th bore or improve the 13mm bore further, its a fixed change not adjustable.
 

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