Front Brake surge

[Speedy1959]

Thanks everyone for your errrr help..

Tyres are about 1,000 miles old so I cant see it being them..
A few days ago I had a good go at freeing of the bobbins. They were all very tight.. They are less tight now but you cannot turn them by hand as in some of the YouTube videos.

[Speedy1959]

Have a read...
http://blackshadow-uk.co.uk/Fitting.html

That's very interesting Froudy..
I have a nasty feeling you may be onto something there !

Thanks for the link

[Andre]

emmm... was a little confused with it being at high speed. Editing that "2" out makes the situation slightly different. 

[seth]

Give the bobbins another good clean with brake cleaner they shouldn't be tight  .
If the discs are very slightly warped(You'd need to check with a dial gauge to find out) you could try heat treating them once the bobbins are nice and free (not lose) remove the discs put them in the oven on full blast all day then turn off and leave all night to cool.
this can relive the stress in the discs .
it works if they are no to bad .
I think first thing should be to really clean the bobbins then go give it a good run using the brakes (Not overly tho) to get the discs nice and warmed up and see if it helps .

[Speedy1959]

Once again Seth I thank you for your advice...
Earlier I really scrubbed them with a pan scrub and contact cleaner to be totally sure they were grease free.
They are substantially better than they were.. So I don't know if contaminated pads could cause this issue (he said clutching at straws).
What temp in the oven?
I have a gas oven with fan assist..

[seth]

If it got better then your looking like doing the right things.
Take out the pads and give them a clean too (a run on every paper should do it ) then give it a run and hopefully much better after that.
As for oven temp as hot as it goes for min 6 hours then off and leave over night.
You need the buttons spotless before trying this .

[turner]

Sorry to come in late to this , but was it after your bike stood in garage for a while,Some sintered pads leave a rust type residue on discs . this can cause a symptom like this.if so clean disc with a scouring pad.

[gsxbarmy]

My turn!

Whilst I agree about the bobbins 100% (and they should turn reasonably free), I recall you had your wheels powder coated no so long ago Simon - let me ask, were the hubs which the disks bolt onto absolutely and completely free from powder coat (or anything else for that matter), as the slightest variation in the flatness of the hub and the disk won't sit perfectly flat as it should - which could give the symptoms.

Might also be worth checking the torque of all the disc bolt as well, to check they haven't worked loose now you've done a few miles

[seth]

@gsxbarmy great advice
My heat treating method is a last resort for warped discs and why you should check everything else first .

[Speedy1959]

You are correct Dave I had overlooked the fact about powder coating.
I recall the whole wheel was powdercoated inc where the disc sits.
I mentioned to the guy I asked for those areas to be masked off and he said "wont make a difference as the powder coating is the same thickness on all surfaces"!
Grrrrr
Why am I getting problems months later and not immediately?
Dam..... I had totally overlooked powder coating..
Any idea how to remove powder coating from disc areas WITHOUT knackering the alloy ??

[seth]

A sharp blade and be careful

[Andre]

Why am I getting problems months later and not immediately?

Because DTV takes a while to develop (as mentioned in the link Froudy posted above).

[gsxbarmy]

You are correct Dave I had overlooked the fact about powder coating.
I recall the whole wheel was powdercoated inc where the disc sits.
I mentioned to the guy I asked for those areas to be masked off and he said "wont make a difference as the powder coating is the same thickness on all surfaces"!
Grrrrr
Why am I getting problems months later and not immediately?
Dam..... I had totally overlooked powder coating..
Any idea how to remove powder coating from disc areas WITHOUT knackering the alloy ??

What a dipstick he was then - as whilst only thin, the powdercoat thickness will move the disc out slightly from where it was before, also he can't guarantee a flat finish. 

I agree about the sharp blade (carefully), but I'd maybe something like this Simon: Scotch Brite Wheel
https://www.ebay.co.uk/itm/Satin-Web-ScotchBrite-Metal-Sanding-Wheel-Fine-4-by-2-Section/302219027761?hash=item465da86531:g:aKwAAOSwJH1ZLu6q

a 4" fine one should do nicely, I use these all the time with a drill for getting lacquer off things like fork sliders etc before polishing - use on a low speed drill and gently and they do a good job. Depending on grade will leave very slight scratching (which you can flat with some 2000 grit wet and dry (wet) if you want to) but because the scotch brite wheels are soft should not damage the hub itself (you can get smaller ones for dremels for those hard to get places if you need them). They wear fairly quickly, typically I'd get through one 6" wheel per fork slider, but they are effective. I haven't tried one on powder coat, but can't see why they wouldn't work. As with everything, try on a small piece first. I'm guessing you'd probably need at least a couple, one for each side of the hub. Make sure also to mask off those areas where you don't want powder coat to come off, "just in case you slip" when using a drill - also be aware of the mandrel, you don't want to catch that on the hub either!

The above is just an example so you can see what they are like, search on eBay on "scotchbrite wheel" (link above is to the guys I use, helpful with advice as well if needed)

[Speedy1959]

A solution to my issue.
If I modulate the lever inversly to the surging I should be able to cancel out the side effects of the surging.
The side benefit of this is that following cars will witness a rather fetching brake light display!
Another plus point will be my hightened Ninja like reflexes !
Who says being tight doesnt pay !

[KiwiCol]

Also could only use the brake at higher speeds & coast to a stop?