gregforesi wrote:Mine is silver but it looks a lot like this one HERE and it's been fine. 14mm piston turns the wooden stock brakes into something useful.
Somebody asked me about rebuild kits for it, but at that price...who cares? You'll end up with one handle different from the other though. I did some hacking and welding and adapted the stock lever to that master.
79's had larger wheel caliper pistons and drilling the rotors can help the wet weather performance.
I thought the idea was to go from 14mm up to 16mm (5/8") or am I missing something?
Either a smaller piston at the master, or larger pistons at the wheel, give greater mechanical advantage to the brakes. You could put a longer lever on, or move the lever pivot outboard, but the easiest fix is a master with a smaller piston than the stock 17mm. It's the same deal as why hydraulic jacks have small cylinders pumping into big cylinders. For the same amount of lever effort, a smaller piston in the master will deliver more PSI to the calipers (at the expense of less volume per mm of travel...not an issue here).
2006 GL1800 (Brutus Maximus)
1978 GL1000 (White Trash - 2012 BOTY
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gregforesi wrote:Either a smaller piston at the master, or larger pistons at the wheel, give greater mechanical advantage to the brakes. You could put a longer lever on, or move the lever pivot outboard, but the easiest fix is a master with a smaller piston than the stock 17mm. It's the same deal as why hydraulic jacks have small cylinders pumping into big cylinders. For the same amount of lever effort, a smaller piston in the master will deliver more PSI to the calipers (at the expense of less volume per mm of travel...not an issue here).
That makes sense. Following that logic a smaller master cylinder still would be even "better" but I guess that other factors then come into play so it begs the question:
So what is the sweet spot in terms of master cylinder piston size?
Randakks says "A modern Nissin 5/8" master cylinder absolutely transforms GL1000 braking to near-crotch rocket levels. This unit dramatically reduces lever effort and provides significantly improved feel." http://randakks.com/products/randakks-u ... r-cylinder
I've found, 5/8", 16mm and 14mm units on Ebay that wouldn't look out of place on my bike and are at a reasonable price vs quality promise. I just need to make a decision on which one to go for.
Phil, Have you actually ridden your bike ie are you restoring it? I didn't think the front brake on mine was at all bad. Perhaps I was concentrating on the awful carburation instead. As I am used to Airhead BMWs, I found the front brake OK but I will be changing to braided brake lines in the future as they are a tad spongy. No, I don't plan to divide the front brake pipes.
Present bikes -
BMW R100/7
1989 BMW R100GS-Paris Dakar
MZ ETZ250 Trials
1977 Honda GL1000 GoldWing
Paul Narramore wrote:Phil, Have you actually ridden your bike ie are you restoring it? I didn't think the front brake on mine was at all bad. Perhaps I was concentrating on the awful carburation instead. As I am used to Airhead BMWs, I found the front brake OK but I will be changing to braided brake lines in the future as they are a tad spongy. No, I don't plan to divide the front brake pipes.
No I've not actually ridden it.
There are Ebay suppliers of stainless steel kits for around £75 for pre 1979 bikes. I see there's a supplier of 1979 kits that look like they are what is required if you want to remove the splitter ie only two pipes and a double length banjo for the master cylinder.
I think I'm just over thinking things because I can't get out on it until I have it MOTd and registered.
My original carbs are now working just about perfectly, not under load. It will be interesting to see how it goes once I can get out for a ride.
Rather than spend money unnecessarily, I would wait until you ride the bike as she may be fine. I'm not saying the brakes can't be improved upon but why not test them first?
Paul
Present bikes -
BMW R100/7
1989 BMW R100GS-Paris Dakar
MZ ETZ250 Trials
1977 Honda GL1000 GoldWing
Paul Narramore wrote:Rather than spend money unnecessarily, I would wait until you ride the bike as she may be fine.
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You're probably right. This bike is like a new hobby. My previous bikes and other bike have needed minimum mechanical intervention. I guess I've satisfied my need to prat around with them buy buying bolt on things to keep the wind off, hands warm and gear dry. My main motorcycling focus has been on trips to Scotland and all over Europe not on mechanics so I've had reliable easy maintenance bikes that'll take you to Poland and back in a week. I'll still do that but I guess that I want to GL to be something I jump on, on a nice evening, and go up into the dales for Fish and Chips at Hawes etc. having it as good as I can get it for that purpose.
actually, size does matter.... you have to move a certain volume of fluid to move the pistons in the brakes. the bigger the pistons (e.g. on the 79) the more volume you will need. you either move more by a longer stroke (on a smaller piston), or you have a bigger piston and with a shorter stroke. The mc on these old wings were rather marginal to start off with.
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I have a thread on it, that i havent touched in awhile because my HEL brake lines took FOREVER in the mail.... But I finally got them.... carbon fiber lines, with gold banjos, look amazing, a rear full stainless replacement line
I have a 12.7mm MC piston and couldn't find anyone that had tried on ... at all... I have it, so i will try it, I just got all the brakes hooked up on it , and should fill it up and bleed it, next couple days, I'll let ya know how it feels lol... most say it wont work, but why not try
Just got caught up on a wheel mod.... I do have 76/77's so i guess my pistons would be a tad smaller than yours
Paul Narramore wrote:Rather than spend money unnecessarily, I would wait until you ride the bike as she may be fine. I'm not saying the brakes can't be improved upon but why not test them first?
I took it down for its MOT test today. The brakes are good enough to pass the test but they didn't inspire confidence on the ride down and back to the garage.
I've ordered a new master cylinder and am just considering whether to buy straight replacement new braided brake lines ie keep the splitter or, while I'm spending some money, change them for lines that go straight from the MC to the callipers and remove the splitter. I've read previous posts in this thread and elsewhere and I've not really got to grips with the pros and cons of either keeping or ditching the splitter. I'd be grateful if someone could either point to the benefits of ditching the splitter or tell me why you either kept it or ditched it. My instinct is to keep it but I don't have any real logic to back that up.
No pros or cons either way. IMO Just what ever look you want. A single line to the M/C looks good. Some have trouble bleeding with the splitter. Mine has the splitter. But with braided steel lines.
1976 Goldwing Super Sport
1985 Honda Elite
1976 KZ900 Dragbike
1992 ZX7 Dragbike (KZ900 style motor w/NOS)
and a rotation of various purchases
Randakk approved Carb Rebuilder
Paul Narramore wrote:Rather than spend money unnecessarily, I would wait until you ride the bike as she may be fine. I'm not saying the brakes can't be improved upon but why not test them first?
I took it down for its MOT test today. The brakes are good enough to pass the test but they didn't inspire confidence on the ride down and back to the garage.
I've ordered a new master cylinder and am just considering whether to buy straight replacement new braided brake lines ie keep the splitter or, while I'm spending some money, change them for lines that go straight from the MC to the callipers and remove the splitter. I've read previous posts in this thread and elsewhere and I've not really got to grips with the pros and cons of either keeping or ditching the splitter. I'd be grateful if someone could either point to the benefits of ditching the splitter or tell me why you either kept it or ditched it. My instinct is to keep it but I don't have any real logic to back that up.
Thanks
Phil
What do you mean the "brakes are good enough to pass the test". Do they actually test them in some way?
SnoBrdr wrote:What do you mean the "brakes are good enough to pass the test". Do they actually test them in some way?
They have a rolling road connected to some electronics. The tester sits on your bike with first the front wheel sitting in the rollers. He has a remote control and brings the rollers up to speed. He applies the rear brake just to stop the bike moving backwards when he applies the front brake. He then gives the front brake a good hard pull and the display shows how much resistance is created. He said they are "good enough and they locked up". He then did the rear in the same way again, "good enough".
I live in quite a hilly area and the junction at the bottom of my road is on a slope and I felt like I needed to will the bike to stop. How I feel about the GLs brakes is probably because I had an R1150RT for 10 years until recently (the one with servo assisted brakes!!!) and my other current bike is one of the last oil cooled R1200GS which also has awesome but more conventional brakes.
This was my first ride on the bike and I have to say it is an awesome beast, I love it. Riding away from the testing centre with no registration plate amused the next guy who was on a Harley.
I think I'm going to remove the splitter. I can't see any real benefit to it and it seems to me that it's a pretty good place for air to hide in the system.
Personally, I don't like the look of two brake lines coming off the handlebars. But that's only aesthetics. As Robin says above, it's half a dozen of one, and six of the other... I think it's cool that they actually test the effectiveness of the braking system. Some vehicles I see on the road around here seem to be nothing short of death-traps, yet I'll get pulled over if my headlight flickers!
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'77 gl1000, roller parts bike.
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