Home
It is currently Sun Dec 17, 2017 8:52 am

All times are UTC [ DST ]




Post new topic Reply to topic  [ 16 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Fri Sep 25, 2009 10:27 am 
Offline

Joined: Fri Jun 30, 2006 9:47 am
Posts: 148
Location: Hockley
I bought the CBR600F about a year ago with only 700 miles on the clock, although it was already two years old. I have since done about 3000 miles on the bike.
On three separate occasions under heavy braking I have experienced very severe brake judder which causes the bike to "bounce" rapidly, which considerably reduces braking force and, on one occasion, very nearly brown trousers (Druids corner!). I thought the problem was coming from the front end, but after I experienced the problem at Brands an instructor suggested I might have been using too much back brake and that the problem was starting at the back wheel and transferring to the front.
My main bike is a Blackbird which has linked brakes and it may be I have become heavy handed with my use of the back brake without realising it. The instructor at Brands pointed out I would be better off only using the front brake anyway, but I find it hard to stop using the back brake out of habit.
This may well be the answer, but the brake fluid has not yet been changed and I am still running on the original tyres, which are crap and will be changed very shortly. The brakes are not binding and the discs are not warped, so far as I can tell.
Has anyone else experienced anything similar, as it is doing my head in and causing a loss of confidence in the bike and me!!! Any suggestions will be much appreciated.


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 12:35 pm 
Offline
User avatar

Joined: Wed Sep 07, 2005 8:49 am
Posts: 254
Andy, almost glad to hear of a similar problem. My GSXR does exactly the same - blamed it on Guy ragging it in Wales :lol: :lol: , but i really noticed it under heavy braking at the end of the back straight at Snetterton, (hardest i have braked :oops: :oops: ) yet to check in to it fully, but my brother had same problem on his ZZR and turned out to be the floating discs, get corroded / shitty and then cannot float and simulates a warped disc. At his suggestion i have tapped with a mallet all the bobbins that support the disc, and it has improved it a lot, keep promising to drop out the front wheel to clean / lubricate with out risk to the pads. But as off yet too many other things take preference after all not too safety critical is it :oops: :oops: :oops: hope this helps - try a little tap and see..


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 1:09 pm 
Offline
User avatar

Joined: Thu Jun 02, 2005 11:58 am
Posts: 226
Location: on the patio, with a cold beer!!
Having not seen the Brands thing I can't say that the instructor is right or wrong. However, heavy use of the back brake will just cause the wheel to lock up. it may well skip a bit as the weight is right over the front but in my experience, unlikely to cause the front to judder in the way you describe.

The obvious is warped discs but you say they are fine, any warp would manifest itself under light braking.
Head bearings might be part of the problem, and a relatively easy check.

My guess would be suspension, the 600f has (reportedly, I have never ridden one so don't speak from experience) quite soft front suspension, if you are loading up the front to the point of it bottoming out then all you have left is the tyre and the road/track surface. This will give you the juddering you are describing because the front end is now locked solid which means even the slightest bump. however small, will be transmitted straight back through the bars to you.

Imagine riding a rigid forked bike with solid tyres, that is what is created when you run out of suspension with the front end under heavy load.

Not saying this is right or wrong, just an idea as to what might be the problem.

_________________
It's the guests that make the party great


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 1:37 pm 
Offline

Joined: Fri Jun 30, 2006 9:47 am
Posts: 148
Location: Hockley
Thanks for the tips guys.

The front forks have been set up by MCT with new springs etc to overcome the softness of the originals and I have experienced the judder both before and after the springs were done, so I don't think that's it. I had thought about taking everything apart and changing the fluid at the same time and I think I will try that next. I will check the discs again as well.


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 2:33 pm 
Offline
User avatar

Joined: Thu Sep 29, 2005 9:57 am
Posts: 1011
pm sent :wink: (just before your last post).

Regards

Phil

_________________
http://www.leighlockandsafe.co.uk


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 4:10 pm 
Offline

Joined: Fri Jun 30, 2006 9:47 am
Posts: 148
Location: Hockley
Sorry to be a bit thick Phil, but how do I access my PM's?

I bet you've been talking to your instructor mate who I was following when I had the problem at Druids!!!


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 5:25 pm 
Offline
User avatar

Joined: Thu Sep 29, 2005 9:57 am
Posts: 1011
Andy Lee wrote:
Sorry to be a bit thick Phil, but how do I access my PM's?


Hi Andy, login 1st and then look just below the EAMG logo and you will see this,

Logout [ Andy Lee ] 1 new messages

Just click on new messages and open new messages.

Andy Lee wrote:

I bet you've been talking to your instructor mate who I was following when I had the problem at Druids!!!


I forgot you had even been on track until today, no my friend had not mentioned your track day.

Phil

_________________
http://www.leighlockandsafe.co.uk


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 5:54 pm 
Offline

Joined: Fri Jun 30, 2006 9:47 am
Posts: 148
Location: Hockley
Tried that, but it shows 0 messages. Did you send it to the right Andy?


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 7:02 pm 
Offline
User avatar

Joined: Thu Sep 29, 2005 9:57 am
Posts: 1011
Andy Lee wrote:
Tried that, but it shows 0 messages. Did you send it to the right Andy?


Yeah I did. Oh well, I will have to do it again, took me ages probably 30mins or so :? . Pm me your email and I will reply...

Phil

_________________
http://www.leighlockandsafe.co.uk


Top
 Profile  
 
PostPosted: Fri Sep 25, 2009 8:00 pm 
Offline
User avatar

Joined: Thu Sep 29, 2005 9:57 am
Posts: 1011
Andy, my email philhreader@aol.com

_________________
http://www.leighlockandsafe.co.uk


Top
 Profile  
 
PostPosted: Thu Oct 01, 2009 12:52 pm 
Offline
Site Admin
User avatar

Joined: Wed Aug 25, 2004 9:00 am
Posts: 545
Location: Too close to Harlow!!!
CBR600F models have a known weakness with warping front disks - they are normally replaced once by Honda as a goodwill gesture even when several years out of normal warranty. The issue affects model years FX / FY onwards (1999/2000 onwards). It would ceratinly be worth a call to Honda who I'm sure will advise on the state of any 'goodwill' fix.

Chris

_________________
Fast Fat Bloke!!!


Top
 Profile  
 
PostPosted: Thu Oct 01, 2009 10:45 pm 
Offline
User avatar

Joined: Sat Apr 26, 2008 1:08 pm
Posts: 683
Location: 'arlow
I'm new to all this but I have a CBR600F and perhaps don't have warped disks.

It's very very common that the bobbins that allow the float beteen the inner and outter brake disk get clogged up and result in an effect like you describe.

Various fixes ranges from lubricating them (obviously you don't want this to fling out onto the disk though) to putting a bolt through them and tighten it until you can turn it and then work it loose.

An example of this being discussed can be found here :

http://www.bikersoracle.com/cbr600/foru ... hp?t=10135

p.s. I've had it before and have it again currently. I find that when we've had a dry spell we get it and then just a bit of rain and it goes away for ages.

_________________
Paul


Top
 Profile  
 
PostPosted: Sun Oct 04, 2009 10:42 am 
Offline

Joined: Fri Jun 30, 2006 9:47 am
Posts: 148
Location: Hockley
Thanks lads for the further info and tips. I guess I will just have to work my way through the various possibilities and try and discount or proove each theory in turn until I am just left with me! Although, by the sounds of it, I'm not the only one to suffer from this problem. I need to get to the bottom of it though, because under emergency braking it could well be a safety issue. Even with the very best forward planning, you can't stop someone pulling out on you and when the judder happens the braking effect is about half normal.

Andy


Top
 Profile  
 
PostPosted: Sun Oct 04, 2009 10:54 am 
Offline
User avatar

Joined: Sat Apr 26, 2008 1:08 pm
Posts: 683
Location: 'arlow
It seems similar to what I posted but I find I only get this when on moderate braking and hence an emergency stop wouldn't be affected.
Maybe it's not this but gotta be worth a go before you splash the cash :wink:

_________________
Paul


Top
 Profile  
 
PostPosted: Mon Dec 07, 2009 11:27 am 
Offline
User avatar

Joined: Fri Sep 17, 2004 1:43 pm
Posts: 198
Location: Just over the border .....
Hi Andy

For what's it's worth I've 50,000 miles on a CBR600FY in the last 8 years and it's a fantastic bike. However I had the same problem after about 4000 miles. It was warped discs and Honda replaced them even though it was out of warranty (they know it's a problem). I have subsiquently had a second set since then.
Bear in mind Andy that the warp probably won't be visible. They need to be checked on something like a static wheel balancer jig. You can then check them as you rotate against a fixed datum point.

Do you get a pulsing throught the brake lever ? if so it's discs. I can't see that changing the fluid would have any effect on this at all, but the seized floating bobbins will.

Keep us all posted.

Stuart


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 16 posts ]  Go to page 1, 2  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron