VFR800 rear brake doing something odd when stopped.

[c_dug]

Hi All,

I got a new to me VFR800 on Friday just gone, I've come across a bit of a niggle that I can't get my head around.

I was filtering through tight traffic this morning and I consistently found that as I came to a complete stop and the bike rocked backwards a bit from the front suspension decompressing I would lose brake pressure on the rear brake.

If I pumped the brake pedal it would quickly regain pressure and it doesn't appear to lose pressure at any other point, only when it rocks back in that way. It doesn't lose pressure overnight, and it doesn't lose pressure when using the brake to slow over a long distance, purely when completely stopped.

The brake still seems to be holding the bike still with enough force to stall the engine if I try and pull away with it pressed, but the pedal feels to have dropped a good inch or two from where it normally bites.

Any ideas?

Brakes are non-abs linked jobbies if it makes any difference.
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[nowhere.elysium]

[shot in the dark]I'd be chalking that up to the linked brake voodoo. It sounds like pressure's equalizing between the brake systems as you apply more of the front brake, causing the brake pedal to 'sag' like that.[/shot in the dark]
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[carlosvalderr...]

I'm not sure if it's on the VFR800, but some linked Hondas attach a front caliper to a little master cylinder.

As the caliper grips the disc, the master cylinder is actuated, which pressurises the rear system.

It could be that as you stop, the spring extension and top out is putting a little counter-rotation into the front wheel, and instead of pressing on the master cylinder, the caliper is drawing on it, which could then react by drawing the rear piston into the caliper a little.

However, I'm making this shit up as I go along, and I'd be surprised if Honda didn't stick a check valve, or a mechanical stop on the caliper to prevent this...

[Ribenapigeon]

Id pop out the pads and give both brakes a good clean. Its the cheapest first fix you can do before going all brake stripping or handing your wallet to a mechanic.

[c_dug]

Well I've sussed the problem.

Brake pads just shat themselves somewhere along embankment.

Guess which cunt is stuck at the side of the road!

Go new bike!
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Ribenapigeon]

Wow nasty. Sorry to hear that. Who sold you a bike with duff brakes? Are you going to go back to them?

[c_dug]

Private sale. Unsure where I stand but it isn't the first issue I've had, pretty fucking angry to say the least.
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Pol Anorl]

ad say sold as seen ?

if not ride it through his window claim you couldn't stop because he used his cabbage brain and ham fists to fit brake pads.
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[Ribenapigeon]

[c_dug]

Receipt says it. Don't think it holds much legal standing but I'm unsure if I can claim misrepresentation when I've had a chance to take it for a test ride and stuff before buying.
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Ribenapigeon]

[Pete.]

Pads came out or just shed their linings?
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[MCN]

Private Sales are not covered by the same (watery) rules as dealer sales.
Probably have to suck it up.
I'd pop around and chin the bastirt for the price of a set of pads.
Can only say fcuk off.
Then launch the old ones through his living room window.

[c_dug]

Pads came out. Have had a chance to inspect now with the recover driver.

Turns out one pad hadn't had the pin put through it, the pin is still securely in the calliper and through the other pad.

It's chewed the anti rattle spring but everything else seems mostly intact. Time to break out the spanners
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Casper]

Few fucking drama queens. New pads and get on with your life. Private sale, trading standards for brake pads. Yeah right. This country is turning into America more each year.

[Pete.]

[c_dug]

To be fair the brakes aren't the only issue I've come across, it's the second time in a week I've been left at the side of the road, as you can imagine I'm pretty pissed off.

Caveat Emptor and all that jazz I guess.
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I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Ribenapigeon]

[stinkwheel]

Mind you.

Mis-fitted brake pads are a long way from the worst thing I've seen on a second hand bike.

So, taking the degree of mechanical ability shown with that particular fix. Go check everything else.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MCN]

[chris-red]

Here is a lesson for you all folks, if you have brake issues investigate!

I felt a slight knock/rattle from the front of my TDM, I thought it was a loose fairing/mudguard when I got home I had an prod about and couldn't find anything. Was gonna go inside but though I'll have a better look, got a torch out and saw one of my calipers was missing a bolt and the other was only holding on by a few threads

Dunno how it happened the other side was tight, and they hadn't been touched for ages, I was suspicious of tampering but just chalked it up not torquing it up properly.
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[Doovy]

Jesus Con, I swear you are the most unluckiest guy I know on a bike
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[c_dug]

Honestly I really do!

I thought I'd spend a bit of money and get a nice bike, less trouble I told myself. Clearly that's worked well.

Seller is claiming ignorance to any of the issues, can't say I expected any less to be honest, but it was worth a try speaking to him.

Actually I get the impression he never did his own maintenance on the bike so I'd say it's more likely a dodgy garage job that he was unaware of, just pot luck that it happened to me and not him!

I've got breakdown cover now anyway, not that it saved me the £130 last night. Hopefully I can get it into some sort of reliable condition before Friday (BBQ)!
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Ribenapigeon]

[MCN]