I submitted this before.
This is from a personal email reply I sent hobot about his Norton front brake master cylinder brake upgrade (hot nail through the rubber piece). He asked that I post it public, I included his reply at the bottom.
Me:
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.
hobot:
Alrighty David you got about as much as one can expect form the factory hydraulic ratio do appreciate hearing how much just a bigger hole makes for actually having a lockable brake. Its somewhat a safety feature it takes so much effort to squeal at good speed but guarantee if a panic need arises it wont hardly noticed. I got a decent grip so not much a bother to me to squeal at will. Next thing to improve the ease is get something like the RGM race lever and SS hose. Do not mistake ease of squeaze with actual stopping distance once a loud squeal or lock up can be had then that's all there is from two fingers or ham fisted grab. Once pistons or pucks get rusty they are more prone to re-rust and mess with bore pitting. Your email would be fun to read on forum with a title like hobot brake mod let down : )
mightydaj,
Feb 23, 2015
