Hi, Yea ok, Yes I'm asking even though I get the be there thing. It has come to me after a while of riding that the rear brake is just not acting like it should in the way of feel and action. SMH, these linked brakes are for the birds and even that is being to nice to say. What's going on is the rear brake lever action is somewhat firm like one would expect, except there really isn't much in the way of braking going on. I really have to almost stomp on it to get what I'd call a decent amount of feed back letting me know it's working. Yes, This has been bugging me since I've had this 5th gen from Aug. last year, but I've only just now started to really get in the riding. anyway after reading a lot of this and that here and VFRD that the rear brake is a devil to bleed as I'm thinking that would help answer part of the question what the H is going on. At first I put it as it's linked brakes , just the way it is, now I'm not so sure. LOL if there was another 5th or maybe a 6th to try for comparison that would help, but there ain't any around for a simple check. I just wanted to hear if anyone else has had something familiar and what they found. the fronts act pretty darn good, just the rear is very questionable.
Flush the brake fluid ... make sure you also bleed and flush the proportional control valves. If you don't, it leaves shitty brake fluid in there and can make the dual linked brake system work like shit. When bleeding the proportional control valves, you have to actuate the valves that control them in order to bleed (ie; pump the front brake caliper itself back and forth on the front left and the rear brake lever for the other).
My 5th has the same issue. I don't usually use the back brake, but I have been trying to more, though the reason for that I guess is just to activate the extra piston in front. (Do 5th gen brakes work the same as 6th?) I know the front was flushed by the P.O. when he replaced the front forks. I doubt he did the back, therefor, probably the whole system needs redone. I've got new pads to put on it, as my tire peeps said that the rear pads were toast, but they are only about half worn.
I flushed and bled the whole system and followed the manual to a T. It took awhile, but once I was done no issues and I rather like how the linked system works. Follow the shop manual and you'll be set.
Thanks guys, yea it's just weird. I know from previous experience from what I call normal braking practice. I use the rear a bit more depending on what's going on in the ride at hand. I've learned and felt what works from the track and a lot of spirited riding. I get it. But I kinda figured from the get go I would need to get a feel for this linked brake thing, it's getting the better of me though. As soon as I can these are going by by. That said in the mean time thought after yesterdays out n about I'd look a little deeper in whats going on. I'm pretty good at brake bleeding, this just has me a bit leery whats going on. just hard to figure if that's the way they are, or if there's a hang up and where to start. The fronts are perfect considering. I'll add that the PO was great at maintenance, the fluids are clear like they had just been flushed, the clutch as well. My thinking first off is it's not a fluid issue. Could be just me wanting more than it can deliver, but still odd. You guys need to be closer so I could compare.
The only problem I had on my 5 Gen (bought used) was the two outer pistons in the rear caliper were nicked and were rubbing away the seals gumming them up so the rear calipers wasn't working at all! A caliper rebuild and flush/fill as well as a brake line upgrade, the rear works now BUT the pedal does feel different than my 6 Gen. However, I can step on just the rear pedal and bring the bike to a stop in decent distance. The main difference in the way the 5 Gen vs. the 6 Gen works is primarily in the front, where the front brake lever does the two outer pistons on each front caliper and the rear pedal does the center piston on both calipers. There is also a "delay valve" on the front but I don't believe that affects the rear brake. As to where the systems are similar is the secondary master cylinder, which applies the center piston of the rear caliper and the rear pedal does the two outer pistons. Personally I think as long as the delay valve and proportional valves are in good working order, the linked braking system shouldn't be an issue or concern. Bleeding, although can be a huge PITA, once it's done the brakes work as well as any system I have experience with. YMMV
Well, I'm on a 6th gen, but I'm not sure if the linked brakes are the same. Fluid will DEFINITELY impact how well those rear pistons hold ... even if it's clear, it doesn't mean that the proportional valves were flushed and bled, and these can make your rear feel mushy. When I just did my fluids a few weeks ago, I could feel a BIG difference. It will never feel as solid as the front though. EDIT: OOTV nailed what I was attempting to explain.
I had exactly the same problem on mine, the rear worked but not how I expected it to. You've got air in there ,bleed ,bleed and bleed some more. I pumped the rear brake lever,then pump the smc on the front brake and bleed the valve under the tank again and again and again. After I got truly fed up I then pumped the rear brake lever while bleeding the rear caliper.Rode it a month or so then cracked the nipple on the rear caliper and got the last remaining air out .I never want to do this again but know I'll have to .It really is one he'll of a job.
As most would imagine, doing the bleed process solo can be not only time consuming but a little difficult if you have traditional bleeders. Especially when you need to bleed the front SMC and rear proportional valve. Although I have done this solo, I have speed bleeders so the process is much easier but having a helper makes it go much easier. Long and I have done this on his bike as well as Mofo's in my garage and other than him drinking all my IPA :wink: , it was fun hanging out and getting something important done and done well! Of course this means the IPA was drank AFTER we bled the system...right?
If you have a hand vacuum tool for brakes, it makes this job ridiculously easy. Best $35 I've ever spent.
I have a Mighty Vac and would not even think of doing brakes without it. Did my VFR last month and the linked brakes are a pain in the ass but the vac made it tolerable.
I am slightly concerned that you may actually be trying to dial out something which is actually implicit in the 5th gen braking system. So your idea of comparing it with the brakes on another VFR is a sound one. IIRC the linked brake system fitted on 5th Gen VFRs is not the same as that fitted to 6th gen models which had a more refined system, which noticeably changed the rear/front braking effect. What you describe (the rear brake seemingly not working very well) is not entirely surprising. Basically on the 5th gen models the rear brake only applies braking force to 2 pistons on the rear disc and to two pistons on the front discs - inevitably this will make it feel like the rear brake is not very effective. For the 6th Gens they changed the set up to give a more obvious rear/front brake bias. To do this the rear brake on 6th gens applies braking force onto 3 of the 4 pistons on the rear caliper and only one of the front caliper pistons. This significantly changes how the brake effect feels. Meantime the front brake on the 6th gen applies braking force onto 5 of the 6 front pistons meaning it has a far more obvious front brake bias but it still operates (indirectly) one of the rear caliper pistons - to ensure that especially in an emergency braking situation, the rear brake will be applied and the available grip on the rear tyre will therefore contribute to the braking effort. Inherently Honda realised that the brake balance on the 5th gen set-up was not ideal but it is what Honda delivered. If you are still uneasy about the brakes on your bike it is probably worth arranging a brake test session at a rolling road facility to check out the comparative effect on front and rear tyres of applying in turn the front and then the rear brakes which should give you 4 separate brake effect readings. Personally I owe my life to the effectiveness of the linked ABS brakes on my 6th gen, so I am very glad to have a bike with the system. Whilst doubtless there are some top flight riders like Marquez and Rossi who using a conventional brake set up, can out-perform the braking achieved by a linked ABS system but I know am not one. Indeed the system proved itself a few years back when I rounded a corner in the Alps at speed on my side of the road to be suddenly confronted with an idiot in a van rapidly heading towards me on my side of the road, who despite the obvious blind bend just yards ahead, had decided it was a suitable place to overtake a caravan. Suffice to say my first reaction was **** and to apply a total death grip on the front brake and try to steer the bike through the narrow gap remaining between the van and the hillside. At no stage did I think of, or even remember to make use of, the rear brake - but of course Mr Honda had that covered for me and amazingly the ABS just did its thing allowing me to simultaneously apply maximum braking and steer the bike enough to somehow squeeze through the gap. By the time I had brought the bike to a halt I was really shaking and it took a few minutes before I felt ready to move off again. Suffice to say the van and caravan were long gone. Whatever you decide to do with your brakes - take care SkiMad
BTW, the Mity-Vac does not work with speed bleeders, at least at the typical PSI used for standard bleeders. You'll still need to squeeze the lever or press the pedal. I find that one or the other makes bleeding a snap.
I find the rear brake extremely effective. I use it at stoplights really just to exercise it and know that it is working. Of course there is no way for me to tell how much braking force is applied rear vs. front. All I know is the rear brake lever applies a fairly large braking force. If it is completely ineffective then something is wrong. The ideas above of gum in the proportioning valves or air in the system sound likely. Secondly, Jay have you had the rear calipers apart at some point? I wonder if they are sticking from nicked pistons and gummy seals. However I think I know how meticulous you are. Also knowing that the rear also should apply the front, then concern for sticking pistons and gummy seals in the rear seems less likely in your case.
I read this somewhere - I wonder why this is? Just requires more vacuum I guess to get the valve in the speed bleeder to work??
Skimad thanks and whoa, I can only imagine that pucker factor, wow. Yep Knight while on thewheel and shock i gave it a really good going over and cleaning seeing if there was any reason to go further an there wasn't. so no I didn't tke em all apart as I didn't see anything that told me that would be a smart thing to do. If it can work out Powderrecon from here might be able to make a meet up work this week end. So with a bit of checking this and that it may tell me whats up. Here's the interesting part since I don't have another 5th gen to compare yet, I dug into the shop manual seeing how these work. never really told me much other than how it's put together. Then Skimad brought more light to it which now makes a lot of sense, for the time being it's me that's looking for a more efficient bite. Small test here today when I was checking the chain I went ahead and used hand pressure on the brake pedal, and low and behold it didn't take much to feel friction push a bit more, more bite, to the point I could hold down the brake lever and not rotate the wheel. interesting. Then the light bulb went on,, I should have thought it worked, SMH, when I did the rear wheel & shock LOL I used the rear break to hold the wheel so I could undo the lug nuts. and vise versa, used it to hold it while tighten em up too. Doh!!!! so it must be working just not like I would have thought.. again SMH.. Still will be interesting to do a comparison, who knows, now maybe it's the pads?
I also posted this on one of the VFRD brake bleeding threads, so maybe that's where but yes, the amount of force required to trigger the check valve appears to be a lot more than what you normally use to draw fluid through a standard bleeder. I had my Mity-vac up to about 10 PSI above the recommended value and that still didn't trigger the check valve.
