bad disk brake performance

Flo said:

So what are you all getting at?
I do a lot of 2 up riding & the front brake leaves a lot to be desired.
Maybe I should slow down? I didn't buy a Commando to poodle around.

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If you are not going to be able to stop in time, you definitely need to ride to the conditions.
Only fools would think otherwise.

Pics of Commandos with superlarge or twin discs abound, obviously good brakes are available.

P.S. Honda 4s had twin disks available as an option when Commandos were new..
Obviously some makers valued their riders more than others... ?

I brought the brembo 4 piston brake, with mounting kit from British spares, complete with master cylinder, brake caliper, floating disc. It's expensive and it's also awesome. the brake caliper is chromed and looks great.

I own 3 bikes, two modern and the Norton. The problem with that is I found myself surprised a few times on the norton my it's inability to stop by modern standards!

The stock caliper, in its era, was one of the best. No one knocks the Yamaha TZ/RD350 caliper of that era - they are almost identical. The problem was always the dummy who spec'd the diameter of the Norton's master cylinder's piston. Yamaha's engineer got that part right, the Norton guy, well . . . . . .

With just the master cylinder sleeve mod, braided stainless lines, and "racing" pads, the Commando's front brake is more than adequate. Yes, I admit that it would be nice if I could use still less effort.

I weigh 260 pounds and going downhill is one place where my Norton can give lessons to her younger relations. The youngsters' superior acceleration advantage is attenuated in the downhill mode and while the kids do have double disc four pots, they aren't that much better. After one spirited descent, a duly impressed fellow rider, studying my Norton, pointed to her front disc and said "look at those cracks!" Every single hole in the center set of drillings was cracked radially.

http://s814.photobucket.com/albums/zz67/xbacksideslider/Cracked Norton Disc/

I no longer run a drilled disc and despite similar downhill runs, the replacement disc has not warped.

My experience of good brakes started with my SV650 in '01, then track school Ninja. Then I finished Peel, 12 mm m/c, ss hose, RGM race lever and 1.5 lb lighter rotor on 110x19 Dunlop dual purpose grooved tire. On Ninja I gritted teeth to creep up on pull down until stoppies occurred, [jerked on track for intense warning lecture] But I then Knew what I could get away with, Before I began reason to attend school, test theory that there is no difference riding THE Gravel or Tarmac if attacked harsh enough its as loose as a goose too. I got much more handy on SV after the school, but not so much what they taught me as no oncoming traffic on a track.

I lived on Ms Peel about a year after school, first time I had a flat or her I just hopped on SV to return to work and almost crashed by stoppies going by the pull down ease of Peel and also got surprised by unexpected pop up wheelies, just going by the pull of Peel just commuting sanely I thought. The moderns may have the most powerful brakes but they sure can't use all the power and grip to stop as short as a long low Commando can. Peel was so good I tried stoppie many times but all that happened was I could not stay in seat on the intense deceleration or ending up riding locked front for a few bike lengths. Rear would only lift enough to totally unload rear then required butt power to keep it from passing front.

I brake serious hard before reaching crests or going into blind turns, I brake seriously on mail box shaped that freak me out as if deer, I brake seriously for tiny bits of foil after dark as freaked out its deer eye reflection. Serous braking is very near and dear to me. I've yet to experience one as secure at on obsolete Md Peel. 0>100>0 times is part of Peel's purpose to find her pecking order among all comers. Part of Peel's purpose is to rub the elites nose in the dust using apparently such obsolete technology.

BTW I now believe the tnnie tiny orifice in rubber end of piston stack was to restrict full brake effect to mimic drums. Remove it and get a distinct better feel w/o doing anything else. That is all I'm allowing my self to deviate from factory on Trixie. None of the resleeve jobs have any restrictor orifice.

xbacksideslider said:

After one spirited descent, a duly impressed fellow rider, studying my Norton, pointed to her front disc and said "look at those cracks!" Every single hole in the center set of drillings was cracked radially.

http://s814.photobucket.com/albums/zz67/xbacksideslider/Cracked Norton Disc/

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Who drilled that disc ?
They weren't done with a pilot hole first ?

Rohan said:

xbacksideslider said:

After one spirited descent, a duly impressed fellow rider, studying my Norton, pointed to her front disc and said "look at those cracks!" Every single hole in the center set of drillings was cracked radially.

http://s814.photobucket.com/albums/zz67/xbacksideslider/Cracked Norton Disc/

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Who drilled that disc ?
They weren't done with a pilot hole first ?

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No idea. Good point about the pilot hole. Got the disc 2nd hand. The holes were barely chamfered too which was OK by me as my idea was that chamfering steals even more swept area.

Rohan said:

john robert bould said:

..beats me how pre war manx nortons with single 7in drum laped the island at 90 mph?

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In racing, a lack of whoa can be made up for with more goa.
Doesn't work like that in traffic, however....

Good question though - fearless is probably a word that is involved here. ?

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Flo, Yes the old racers didn't have white van drivers to deal with, but still had to pull up a sign post corner, problem is "we" are comparing the Commando brakes to modern stoppers..i carnt remember MCN slagging off the brakes at the time? But again the roads where not filled with mums taking kids to school in 4x4s on their mobiles,
Six weeks ago a young lad ran into our parked car...yes it was a case of " Love you honey,see you latter...O shit" Bang on his phone,,what a twat!
But if brakes can be improved [a bit]without detracting from stock looks i am all for it, Big Norvil twin disc's must be good, but not for me...I would say too good for a old bike with the increased possibility of skidding, with a chance of increasing a gravel rash risk?

Repeating my self....looking is better than the best brakes. I have only ran into a car once in 43 years..and that was NOT LOOKING! learned me a lesson that as kept me safe...i have drove 380.000 miles in three years, and well over a million total ,Driving with my eyes and reactions focused , and leave a good gap, it really is the the answer....i have seen cars driving 10 feet from the car in front on M Ways at 80 plus...total pricks...then when a rear endder happens, they say" it wasnt me "he" braked" seen it many,many times.
Going back to white van drivers...thats ME!

Chamfering would also help reduce the chances of cracks.
And would also reduce pad wear/damage from rough edges.

When someone conservative like BMW finally went to drilled discs, you just KNOW that drilled discs are better.
And they chamfer the holes.
Took em a long time to go to Brembo calipers though....

xbacksideslider said:

The stock caliper, in its era, was one of the best. No one knocks the Yamaha TZ/RD350 caliper of that era - they are almost identical. The problem was always the dummy who spec'd the diameter of the Norton's master cylinder's piston. Yamaha's engineer got that part right, the Norton guy, well . . . . . .

With just the master cylinder sleeve mod, braided stainless lines, and "racing" pads, the Commando's front brake is more than adequate. Yes, I admit that it would be nice if I could use still less effort.

I weigh 260 pounds and going downhill is one place where my Norton can give lessons to her younger relations. The youngsters' superior acceleration advantage is attenuated in the downhill mode and while the kids do have double disc four pots, they aren't that much better. After one spirited descent, a duly impressed fellow rider, studying my Norton, pointed to her front disc and said "look at those cracks!" Every single hole in the center set of drillings was cracked radially.

http://s814.photobucket.com/albums/zz67/xbacksideslider/Cracked Norton Disc/

I no longer run a drilled disc and despite similar downhill runs, the replacement disc has not warped.

Click to expand...

Strange how my MK 3 passed an M.O.T..on the brake meter it pulled over the required force...the D.O.T have a limit set out by people who know what is required, dont think STOPPIE'S was on the cards :lol:

Not saying better is going to save your bacon lads! infact may be worst in the wet with skinny 4.10x19 up front!

john robert bould said:

Strange how my MK 3 passed an M.O.T..on the brake meter it pulled over the required force...

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The braking efficiency standard for the MOT is not particularly high (30% and 25%) so it's not surprising it passed. http://www.motuk.co.uk/mcmanual_330.htm
http://www.vosa.gov.uk/

john robert bould said:

the D.O.T have a limit set out by people who know what is requireds

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DfT (Department for Transport)
http://www.dft.gov.uk/

L.A.B. said:

john robert bould said:

Strange how my MK 3 passed an M.O.T..on the brake meter it pulled over the required force...

Click to expand...

The braking efficiency standard for the MOT is not particularly high (30% and 25%) so it's not surprising it passed. http://www.motuk.co.uk/mcmanual_330.htm
http://www.vosa.gov.uk/

john robert bould said:

the D.O.T have a limit set out by people who know what is requireds

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DfT (Department for Transport)
http://www.dft.gov.uk/

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Lab, 30% of what? if Commando brakes are [to some] just crap, then 30% of crap ain't a lot :!:

john robert bould said:

Lab, 30% of what?

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It's in the tester's manual, John
http://www.motuk.co.uk/mcmanual_330.htm

The efficiency of each system operated by a single brake control is the ratio of the total retarding force generated by that system divided by the weight of the machine and rider

Total retarding force for one system/weight of machine plus rider (tester) x 100

Motorcycles first registered on or after 1 January 1927 require two means of operating the brakes, one achieving a minimum efficiency of 30% and the other a minimum of 25%

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Can this help???? Half inch sleeve down kit in the master cylinder, the issues is the diameter of the master cylinder. It is five eights of an inch, the kit will reduce it to half inch as per all modern bikes with single disc. It’s like the garden hose with no fitting on the end, wont squirt far, if you narrow the opening with your finger you then have plenty of squirt, same principal.

L.A.B. said:

john robert bould said:

Lab, 30% of what?

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It's in the tester's manual, John
http://www.motuk.co.uk/mcmanual_330.htm

The efficiency of each system operated by a single brake control is the ratio of the total retarding force generated by that system divided by the weight of the machine and rider

Total retarding force for one system/weight of machine plus rider (tester) x 100

Motorcycles first registered on or after 1 January 1927 require two means of operating the brakes, one achieving a minimum efficiency of 30% and the other a minimum of 25%

Click to expand...

Click to expand...

MK 111 said:

Can this help???? Half inch sleeve down kit in the master cylinder, the issues is the diameter of the master cylinder. It is five eights of an inch, the kit will reduce it to half inch as per all modern bikes with single disc.

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Yes, many of us here already use the sleeved-down (13mm) master cylinder conversion-and it is a definite improvement. I expect John would think so too-if he tried it.

Norton factory hydraulic ratio is like 19:1 while modern bikes are like 25-27:1, with 13 mm m/c it raises Lockeheed into the 21-22 ratio.
12mm tends to allow lever to get pretty close to the bars to move enough fluid on big old Norton calipers, more so with dual discs.

Getting back to one of my questions when I resurrected this post: Comments about the RGM brake cylinder sleeve kit (they're not doing the machining right now due to backlog of work) and self-installation. Any of you done this and the results? I have a drill press and compound vise so holding the piece upright should not be a problem.