Front Brake Calipers & Disc
 

Recently purchased a 2005 VTR 1000 with 43,000kms on the clock.

I've noticed under high speed braking (anything 80km/h plus) I get a bit of jitter/vibration when I squeeze the lever. At low speeds, I don't notice it as much or at all.

I've checked and cleaned out the bobbins - they rotate freely with the spanner/bolt trick, but don't rotate freely by hand, and the pads look practically brand new.

My assumption is the discs are warped, and am waiting to hear back from the dealer I bought it from to see how we will proceed on fixing the issue. With the front wheel off the ground, the wheel spins although the pads are in constant contact with the discs. It doesn't even complete a rotation without stopping

While checking out the calipers further, I noticed a bit of corrosion on the pistons. I haven't removed them fully and won't until I know further how the dealer will respond, but as the corrosion is on the outer part of the piston - where it doesn't get pushed back inside the slot - do they need to be replaced or can I try and clean them up?

Attachment 32719

Looking online, a replacement piston is is about $35 USD each, so $140 for a full caliper set (left and right) which is money I'd rather not spend. Do I only need to replace the pistons on the left side of the above image?

If the bike from the dealer came with a warranty - they should be looking at refurbing the brakes with new pistons and seals, and disks if they've warped. A bit shocking that they'd sell it in that state.

Having fully functioning brakes is quite fundamental on a 150mph motorcycle and bodging isn't the answer.

You might want to go over the bike with a fine toothcomb to see what else is amiss.

I have a complete brake set off my VTR (I replaced it with a CBR954 set) that you are welcome to borrow to see if it makes your shudder go away. But my guess is that you more likely have either a slightly bent disc, or a seized disc bobbin. Some have reported that freeing up the bobbins reduced/removed a shudder. If you put a nut and bolt through the bobbin and gently tighten it, you can then rotate the bobbin to work it free.

You can also borrow my front wheel for a comparison ride if that would help (I'm in Auckland).

Thank you very much for the offer, really appreciate it.

The bike is currently back at the dealer (they've had it for 2.5 days now and have no update for me!!!) where they have agreed to look into and fix the problem.

I'll let you know how I get on!

Got a call on Thursday afternoon to come in and check out the bike after they had spent time on it.

The service guy took it for a test ride before working on it and agreed something was wrong.

He explained that he took the lower front end apart and cleaned out the calipers etc. and put everything back together. I was told the discs were well within run-out spec. and that the vibration had improved but it was still there slightly.

When I got there, I took it for a test ride and initially didn't feel a thing, however as soon as I got to 70km/h + speeds, the brake shudder/vibration appeared. It's only in the first small movement of the brake lever and once I squeeze it on fully it mostly disappears - however for that portion of braking where it vibrates, it does it a lot - enough that the fairings and bubble screen shake, which is pretty unnerving when braking from high speeds.

I explained my findings to the sales rep, who has said he will order in a replacement left disc, have it fitted to the bike and then we will see what happens. According to the service tech it is coming from the left side of the wheel.

I must admit, they've been bloody great about things so far and I hope there is a positive ending so that everyone is happy. I'm being vague and not naming names on purpose, I'll reserve that for when I know how it ends and if all is well I'm sure there'll be a box of beer in it for the Sales rep

I'm a bit familiar with brake judder as I have a minor case of it on my VFR. I tried a replacement 2nd hand disc from EBay which looked great and had little runout at the rim, but shook the bike hard enough to jolt one of the indicator bulbs out of its socket. Turns out the disc had originally been mounted not flat to the wheel, and had worn "straight" provided it stayed in a crooked mount. I put my original disc back on and the eBay retailer (Steeles Cycles)kindly refunded both my shipping and the purchase price. Sound like your dealer is playing a straight game, End, which is good news. If it all turns out well, I'm sure you'll name names.