ZZR1400 Gen 1 - Bad shaking under braking

[Nope.]

Hi BCF'ers,

I recently procured a ZZR1400 Gen 1 with ABS (09 plate) at a very reasonable price knowing it needed a few bits and pieces - namely a battery and set of front brake discs (and pads obviously) as they were warped. Picked it up yesterday and sure enough there was pulsing through the lever. I had already ordered a new set of discs and pads, so today I fitted them. I've fitted discs & pads many times and never had any issues.

I was careful to bed them in a bit before I did any hard work on them, but under harsh breaking the whole bike is now shaking. It's not pulsing at the lever, it's a violent and jarring vibration through the whole bike - though it looks much worse than it actually is in terms of braking performance.

My current thoughts are:

1) I've got something slightly wrong on the install and there is something behind one of the discs that's making it uneven.

2) I've been sold brand new discs with a tonne of run out.

3) The floating bobbins are stuck.

4) I have a completely different problem.

I'm going to hopefully find some time tomorrow to strip the front end again and see if I can figure out what on earth is going on, but if anybody has any thoughts I would be most grateful for them!

Many thanks!
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Former: Derbi GP1 50, Sachs XTC 125, Suzuki GSXR 400 GK73A, Kawasaki ZX7R, Suzuki DR250, Yamaha RD350
Current: 2011 Yamaha XT660Z Ténéré, 2003 Yamaha YZR-R1 5PW (In Build), 2009 Kawasaki ZZR1400

[Easy-X]

This would probably be a two-man job but I'd probably try lifting the front end up, spinning the wheel and applying the brake, see if anything obvious jumps out at you.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[doggone]

Steering head bearings? - try the notch test with front lifted up.

[Polarbear]

Lift up the front end with a jack under the engine (has it got a center stand?). Spin the front wheel, you should be able to see any run out or the discs binding on the pads as it turns.

At a guess though I would agree with you and go for something wrong with your assembly or you have a warped disk from new.
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Triumph Trophy Launch Edition

[jeffyjeff]

Don't those brake calipers have opposing pistons on both sides of the disc? When you have the brake apart, you might check to for proper function of the caliper pistons. One or more might be seized.
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History shows again and again how nature points out the folly of men - BOC

[stinkwheel]

If you've ridden it ehough to notice the problem, you might have uneven discolouration on the disc by now showing somewhere where it's gripping unevenly.

In any case, I'd be checking runout. If you don't have a dial guage, you can put a cable tie round the fork leg, snip the spare end off square and position it so it's JUST off touching the disc. Any significant runout should be obvious as you turn the wheel.

Excessive runout on new discs is a thing. I've also had a wheel where the posts the disc bolts to were damaged which made the disc off true. It wasn't by enough to see but I was able to measure it, they had a slight variation in distance from the calliper bracket when it was all bolted in with the disc and calliper off and the disc had vertical runout with a dial guage.

Could you have missed off or poorly fitted a brake pad spring/clip?

Also have a close look at the tyres since it's a new bike. Bad feathering of the tread? Not properly seated on the bead (there is a line going all the way round the tyre just off the bead, it should be the same distance from the rim all the way round)? Tyre on the right way round?
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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.

[Nope.]

Thanks for the replies and advice guys, I appreciate it. I didn't get a chance to look at the bike in any detail today, but I did observe that there is now an uneven wear pattern on, of all things, the ABS reluctor ring which isn't good! Hopefully it hasn't damaged the sensor. Something is clearly wrong so I'm going to strip it down on Thursday and hope I can sort it! Will update when I've figured it out.
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Former: Derbi GP1 50, Sachs XTC 125, Suzuki GSXR 400 GK73A, Kawasaki ZX7R, Suzuki DR250, Yamaha RD350
Current: 2011 Yamaha XT660Z Ténéré, 2003 Yamaha YZR-R1 5PW (In Build), 2009 Kawasaki ZZR1400

[PotatoHead202...]

I had a similar issue with a VFR1200. Turned out the "mechanc" at the Dealers hadn't tightened the steering stem nut properly.

Check the clearences with the ABS sensor and the ring sensor. On the same VFR after I had fitted EBC discs the clearance was way out and it was pretty much unrideable until I'd fitted spacers.
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Suzuki V Strom 1050XT, Honda CBF500 ABS,

[MarJay]

Check the mating surfaces on the wheel do not have any corrosion. It might present itself enough to make the disc not sit flush with the wheel.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Nope.]

Right, so, tonight I took off the front wheel again and removed the discs. I used a green Scotch-Brite pad to clean down the mating surface of any and all corrosion, of which there was a bit on the left hand disc. I also cleaned down the isolator shims that sit between the wheel and the disc, and did my best to visually check the discs for runout - of which I could see none. I cleaned everything down with brake cleaner, and then re-assembled.

Before re-fitting the callipers I used stinkwheel's suggestion of a cable tie around a fork leg to check for runout which showed no runout at all to the naked eye.

I refitted the callipers and everything looked fine and ran clear of everything (including the ABS sensor!).

Riding the bike is now improved significantly over where it was, but the problem still persists. Braking at moderate speeds, or through moderate speeds from high speed, still elicits significant shaking through the front end - but still with no pulsing at the lever.

The only thing I have noticed, and apologies for the quality of the image, is that the inside pads on the left hand calliper appears to have a different colour back than the other pads. I don't know for sure it wasn't like this when new, but I don't think it was. This is possibly indicative of a stuck piston perhaps, though they did retract fine when I put the new pads in.

The only other thought in my mind, is perhaps the new brake discs have thrown off the wheel balance - though I get no discernible vibration at any speed I've noticed unless under braking. This would perhaps explain why it is marginally better now if I happen to have moved the discs into a different position and affected the balance by doing so, but I would expect other symptoms if balance was the issue.

I leave for France in a week, and at best have a day and two evenings to sort the bike. Worst comes to it I'll take one of the others, but I was really hoping to go on this. I'm at the point of dropping it into my favourite local mechanic and hoping he can fit me in, but he's not open until Monday which cuts it a bit fine.

Any thoughts or advice would be appreciated. I will take it for a wheel balance next week anyway to see if it helps.
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Former: Derbi GP1 50, Sachs XTC 125, Suzuki GSXR 400 GK73A, Kawasaki ZX7R, Suzuki DR250, Yamaha RD350
Current: 2011 Yamaha XT660Z Ténéré, 2003 Yamaha YZR-R1 5PW (In Build), 2009 Kawasaki ZZR1400

[stinkwheel]

Balance is easy to check. Take the callipers off and spin the wheel. Mark the 12 o' clock position on the tyre where it stops with chalk and spin it again. If the mark finishes up somewhere different, it's balanced, if it doesn't, you need to add weight next to the mark.

Keep adding weight until the mark stops somewhere different every time. If you can't get it that perfect, add weight until it swaps ends then take half the previous amount off and it'll be pretty close.
____________________
“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.