Master Cylinder Trap valve

I'm installing the new sleeve insert into the Norton/Lockheed MC but the new assembly lacks the trap valve (#11, http://www.oldbritts.com/1973_g22.html). A such, the fluid pressure goes directly to the brake line, which I would have thought would be okay.

Is this a redundant part? Can I retro the old one to fit?

Thanks

BC

The valve isn't used with the sleeve kit.

L.A.B. in the factory m/c, does this trap valve/rubber boot serve any return spring force spacing function?
Had someone try my hot nail trough it for same decent improvement to lock up but, what if just left out like re-sleeve kits?

hobot said:

in the factory m/c, does this trap valve/rubber boot serve any return spring force spacing function?

Click to expand...

It spaces the return spring, so perhaps not a good idea to leave it out altogether unless the spring is lengthened to compensate?

While on the subject of brakes, RGM are selling a Triumph master cylinder (997027M) which has a 13mm bore which they say saves re sleeving the original Norton Master cylinder. Has anyone tried this arrangement with the standard Norton caliper and a stainless braided hose?

Ok LAB just checking assembly safety reasoning. About most me and the other nail hole'r can claim is definitive for sure squealing or lock up to max - instead of thinking ahead before white knocked grip to sort of drag the spin down - but still requires a good strong grip, a safety panic feature to me - while the 12 mm and RGM lever and SS braid and 1.5 lb off the rotor gave like 3 finger action to equal the 2 finger action of moderns I've tested. 13 mm leverage should land somewhere between the above but rather closer to the nail holed improvement.

here is a 1/2" mastercylinder I do. the advantage of this over all other retro fit ones is this one accepts the Lucas switch block. and also has a 2 spade brake light switch for the standard brake light wires.

madass140 said:

here is a 1/2" mastercylinder I do. the advantage of this over all other retro fit ones is this one accepts the Lucas switch block. and also has a 2 spade brake light switch for the standard brake light wires.

Click to expand...

Those look pretty good, they look very similar to what's fitted to my Yamaha XJR 1300? How much do you sell them for ?

for members here $170 which includes standard length stainless braided hose and all fittings , includes Fedex shipping.
plenty of mastercylinders out there but not for Lucas switch block fitment.

hobot said:

Ok LAB just checking assembly safety reasoning. About most me and the other nail hole'r can claim is definitive for sure squealing or lock up to max - instead of thinking ahead before white knocked grip to sort of drag the spin down - but still requires a good strong grip, a safety panic feature to me - while the 12 mm and RGM lever and SS braid and 1.5 lb off the rotor gave like 3 finger action to equal the 2 finger action of moderns I've tested. 13 mm leverage should land somewhere between the above but rather closer to the nail holed improvement.

Click to expand...

Hi Hobot

Could you explain what you mean by Nail Holed? And from reading your last, I take it using the Triumph master cylinder is not too bad an option!

willy mac said:

hobot said:

Ok LAB just checking assembly safety reasoning. About most me and the other nail hole'r can claim is definitive for sure squealing or lock up to max - instead of thinking ahead before white knocked grip to sort of drag the spin down - but still requires a good strong grip, a safety panic feature to me - while the 12 mm and RGM lever and SS braid and 1.5 lb off the rotor gave like 3 finger action to equal the 2 finger action of moderns I've tested. 13 mm leverage should land somewhere between the above but rather closer to the nail holed improvement.

Click to expand...

Could you explain what you mean by Nail Holed?

Click to expand...

According to hobot, enlarging the size of the check/trap valve diaphragm hole (by poking a red hot nail through it) increases the effectiveness of the brake although if it actually does then it appears to defy the laws of physics.

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No, it's not a redundant part at all in the Lockheed m/c.
The design intent is to offer an aid to removing entrapped air when using the hand lever and m/c piston for bleeding.
This is well explained in material available online. Here is one such reference...
http://what-when-how.com/automobile/hyd ... utomobile/
The piston return spring holds it against the bore bottom so deletion does change the spring load as L.A.B. correctly points out.
It also serves to center and cushion the inactive end of the return spring within the bore.
Although available, it is not considered a typical wear part and is deleted from some standard bore repair kits.
I don't believe that omission is meant to indicate it is redundant, simply that you may re-use the undamaged original and save a few pennies.
All the best.

AntrimMan said:

I don't believe that omission is meant to indicate it is redundant, simply that you may re-use the undamaged original and save a few pennies.
All the best.

Click to expand...

Although I can see the use of the check valve in stopping reservsed flow back into the cylinder, there is no way the undamaged original will fit inside the new sleeve. It is simply too large.

I'm going to fit it today without and see how it works.

BC

madass 140 I really like your set up! Do you have one that would work with my MKIII ?

no not for MKlll, I looked in to it but the handlebar center to lever pivot bolt distance was going to be increased so I have canned that for the time being

Understood Madass, you do some quality work there Mister. Cj

Madasss I've got dibs on one of your non-mating to Lockheed bar clamps master cylinders ya know.
Here's a risk takers feedback trying hobot red hot nail trap valve mod. Certainly don't sound like much a help after all : )


Re: disk brake upgrade

Sent: Wed Sep 26, 2012 6:42 am
From: mightydaj
To: hobot
Sorry I did not reply back sooner. I wanted to do your upgrade and get some riding time on it for evulation of the difference. Plus I am not known here so I get no private messages and don't even think to look here for them.
Well I did do your upgrade, but only partially evualted the difference. I haven't gotten in very many rides on it since then (lots of different reasons) but at least enough for an initial aprisal. However I cannot make a true direct comparison as there were other factors also. This is what I did.
My Norton (1974 850) had a master cylinder leak since I got it (2 years ago). It did not leak too bad, but every once in a while the front brake lever would go all the way to the grip with no resistanse (scarry sensation). The next pull or two would restablish fluid pressure and it would hold good pressure. So it was ridable as long as space was left in case the first pull failed. But the cylinder did need fixing, so that was done along with your upgrade. The cylinder was cleaned then honed out with fine sandpaper (it had some rust and lots of crud but mostly in the area not swept by the piston). It looked good after I was finished. The piston was pretty rough and rusty (about 1/2 of it) but it also cleaned up ok. I cleaned everything up real good. I got a brake kit from Old Brits and replaced the rubber parts. I then did your upgrade on the old black rubber part with the hot 6 penny nail and put it all back together. I also took the front wheel brake disk off and used a "scott brit" pad on my drill to deglase the disk on both sides. I am no expert on doing that so I hope I did it right. I haven't noticed any puslating so it is probably ok.
So the master cylinder was brought back to normal and the disk deglased along with your upgrade.

My initial finding from the short rides I have done are positive, but not as rosy as your postings. I have found that now it does indeed stop better. I can now even lock up the front wheel if I pull very very very hard. Before that was not possible at all, you could get maybe 1/2 as much stoppage as that, plus it felt totally wooden as they say. It does stop much more evenly now too. Before it seemed to stop somewhat ok at first but then less well as it slowed down (like the same pressure was not slowing it down any further), requiring even harder pulling to get it to stop fully. The stopping distance is now a good bit less, somewhere between 1/3 and 1/2, depending on how hard I pull. It does take less pull to stop, but is by no means an easy pull. The lever still has to be pulled hard, very hard for fast stops. Before it had to be pulled very hard to stop at all. But compared to my 2007 Bonneville, you have to pull more than twice as hard on the Norton. Plus the modulation is way better on the Bonneville, meaning I can lightly change how much pressure and immedeatly feel the difference. The Norton still can't match that, you have to pull hard and pulling harder doesen't have as much effect. It is still more of a on/off brake than a modern. I know I didn't explain that part very well. There is definate improvement. I can't say how much came from any one part of what I did. It is now much much better than it was and is far safer to ride. Before I had to leave lots of room to stop, now I can ride with normal traffic spacing confidently. Thank you for sharing your upgrade with me. The only thing I am dissapointed with is still having to pull so hard. From your posts I was expecting 2 finger operation like my Bonneville. I have a good grip so it is no problem to pull hard, just was looking forward to more, plus I worry that someday I will forget which one I am on and pull the Bonnie's lever at Norton strength and crash. Anyway I do thank your for your help, it has made a big difference. I may still get a sleeved master cylinder later, but for now I will stick with this upgrade and see how it feels as I get more used to it.

I saw your post about Lake Of The Pines. Are you going this year? I want to take my Norton up there this year if I can get 1 more leak fixed, otherwise I will take my Bonnie. I would very much like to meet you in person. How could I identify you (provided you don't mind meeting)?
David Johnson.

Stillreel said:

AntrimMan said:

I don't believe that omission is meant to indicate it is redundant, simply that you may re-use the undamaged original and save a few pennies.
All the best.

Click to expand...

Although I can see the use of the check valve in stopping reservsed flow back into the cylinder, there is no way the undamaged original will fit inside the new sleeve. It is simply too large.

I'm going to fit it today without and see how it works.

BC

Click to expand...

Ahhhh, I see now, I was only referring to use with the standard 5/8" bore. When it comes to sleeving I know nothing but obviously the trap valve may be too large to fit within a reduced diameter.
All the best.

After much fussing, bleeding and splashing around of the blasted brake fluid, it appears the problem may be that the lever is worn at the working end. As such, the piston is not correctly positioned to begin the stroke to build hydraulic pressure. There is significant wear on the lever end that presses the piston so I'm going to shim the thing tomorrow and try again. I was able to determine this by 1) pressing the piston with my thumb into the new sleeve, generating plenty of pressure, 2) inspecting the f'g lever.

I now, officially dislike bleeding the brakes.

More news tomorrow as I still haven't got the thing safetied.

BC

willy mac said:

madass140 said:

here is a 1/2" mastercylinder I do. the advantage of this over all other retro fit ones is this one accepts the Lucas switch block. and also has a 2 spade brake light switch for the standard brake light wires.

Click to expand...

Those look pretty good, they look very similar to what's fitted to my Yamaha XJR 1300? How much do you sell them for ?

Click to expand...

Just received one of these yesterday after it was Fedex'd on Monday from the other side of the world, I've been out on the bike today and the front brake has been improved 100% it actually feels like a proper brake and pulls the bike up with no effort at all.
In my opinion it was well worth it, RGM charge £80 for a re-sleeve of your master cylinder, add another £10 for for postage to and fro and there's not a great deal of difference in cost . If your not bothered about keeping the bike 100% original I'd recommend one of these.