Brake Caliper Mounts At a Funny Angle, Need Pics From Someone Else's Bike!

[LocalRoadKing]

Hello VFRer's,

 

I bought by VFR1200F this year and one of the reoccurring problems I've had is the left front brake caliper sticks, even after rebuilding the calipers and flushing the system. I noticed today that the caliper wants to mount at an angle that isn't flush with the radial mount. I measured the mount and noticed the left one is 3mm farther from the rotor than the right one. How is this possible?? The only thing I've noticed is that there seems to be more space between the fork and the wheel on the left side than the right, as evidenced by the pictures below. My question is, is this normal? Am I following the right path to fix this issue? If someone could let me know that this amount of asymmetric spacing is normal in also on their bike, or even better take some pictures to compare with mine, I would greatly appreciate it!

[ducnut]

Pull your forks together, while snugging your pinch bolts. That’ll center everything. I’ve had to do that on various bikes, over the years.
 

During your next fork service, chuck up the tubes in a lathe and check runout, just be sure of their straightness. 

[LocalRoadKing]

Hmmm, ok, I guess I can get out some ratchet straps and try pulling them together so they are equidistant, but wouldn't this cause the axle bolt to stick out from the caliper mount? Currently they sit flush with each other (picture below) if I pull the forks together, wouldn't it cause this to stick out? Or is it supposed to?

 

 

[ducnut]

You shouldn’t need a ratchet strap. Just reach through the wheel and grab onto the opposite fork leg. 
 

The axle is only going to thread in so far.

[Skids]

HTH

[LocalRoadKing]

Thanks Skids, you pictures look the same as mine, which seems to suggest that my forks are properly spaced apart, but the caliper mounts and the caliper itself seems to suggest they're not. I have no idea what's going on here. When I try to mount up the left caliper, here is a picture of how it want to center itself on the rotor vs how the mount wants to sit:

 

 

[Skids]

That is definitely not right

[LocalRoadKing]

Figured it out, the left rotor is warped, but in a way that has made it cone-shaped. I've never seen warping like that before, I drew a picture below to help illustrate it. Time to go shopping I guess, might roll the dice on used OEM since new is about $1000-1100 for the pair. But thanks for the advice and pictures everyone, I would have kept going down the wrong path otherwise and who knows what I would have done then. Related, has anyone put aftermarket rotors on these bikes and has had a good experience with them? 

[Skids]

Are they that expensive over there?

 

I paid <$200 each for mine.

 

Buy EBC Brakes X Motorcycle Brake Disc - MD4012X | Demon Tweeks (demon-tweeks.com)

 

Either way, glad you figured it out.

 

 

[V4 Rosso]

2 hours ago, Skids said:

Are they that expensive over there?

I was surprised too but checked local prices and yes,over €1000 a pair 😬

 

EBC is fine, so is TRW Lucas that are in the same price range:  <$400 a pair.

[DannoXYZ]

What would be helpful is figuring what caused rotor to warp like that?
Worried that new rotor would get warped like that too.

[VFR750F3]

I would swap the bolts to the other side and see if the caliper is cocked that way.  I think the bolt is bent. 

[Viffy]

Ive seen it before in the UK, The Disc is warped as you said. Proabably got that way with sticking pistons in the past. Also rarely, the master cylinder return hole inside the reservoir under the small deflector plate, can  be bad from new, causing the brakes to drag badly. The bike is so poweful its difficult to feel a dragging brake when on the move.

[LocalRoadKing]

Update:

 

I bought some used OEM rotors from eBay, but they were in much worse condition (gouged, pitted) than what the seller described so I returned them and bought some EBC MD1176X rotors instead. After swapping them out and testing the brakes they feel 100 times better than before. The root cause of my problem was definitely the warped rotor, the wheel spins freely now and the lever has firmed up dramatically now that it's not trying to push on a warped rotor. Thanks again to everyone for the advice, I haven't bedded in the rotors completely so I'll reserve my judgement until then but they fit great onto the wheel. The takeaway? Even if you've flushed the brakes thoroughly and have checked over all components 10 times over, the cause of your problem may be nothing to do with the system you're servicing. Check your rotors!

 

[bmart]

Nice fix...but you'll surely want to find out how ti got warped. If it was leaned on something (some discs are delicate-GSXR), then you can stop doing that. But if it was from use, you'll want to find the root cause so that they'll work properly when you need them. 

 

Also, I believe that the proper term for what you described as your rotor shape might be "dished."

[DannoXYZ]

Yeah, symptoms of problem is warped disc. But actual cause... we'll see...

[LocalRoadKing]

Hey Everyone,

 

So winter has come and gone, and now I finally got a chance to try the bike out with the new rotors. It works perfectly now, the brakes don't drag and they perform great. The rotors were definitely the problem. Thanks for everyone's help!

[Yokel]

On 5/12/2022 at 10:04 PM, LocalRoadKing said:

Hey Everyone,

 

So winter has come and gone, and now I finally got a chance to try the bike out with the new rotors. It works perfectly now, the brakes don't drag and they perform great. The rotors were definitely the problem. Thanks for everyone's help!

Happy endings!

 

Still curious how a stuck caliper piston could have caused that... glad it's resolved!

[Grum]

On 10/31/2021 at 10:45 AM, LocalRoadKing said:

Hmmm, ok, I guess I can get out some ratchet straps and try pulling them together so they are equidistant, but wouldn't this cause the axle bolt to stick out from the caliper mount? Currently they sit flush with each other (picture below) if I pull the forks together, wouldn't it cause this to stick out? Or is it supposed to?

 

 

This is interesting because the axle arrangement appears to be exactly the same as the 8gen.

There have been a couple of issues on this forum and VFRworld where owners are concerned about the left axle face not being exactly flush with the fork face as is mentioned in the 8gen Service Manual. YET the VFR1200 Service Manual makes No mention of making sure the axle and left fork are flush!

 

My own 8gen and many others have stated that the axle positions itself naturally to about 1mm inside the fork from being flush. The last process before tightening the left pinch bolt/s and with both calipers fitted, is to lock the brakes and pump the front forks several times, this will correctly position the left fork, then the left fork pinch bolts are tightened.

The left fork shouldn't be forced to a position it doesn't want to be just to ensure the axle is flush to the fork, this might create a bias to one side of the left disc rotor potentially causing your issue.

 

The fitting of the axle and tightening both the main axle bolt and right side pinch bolts pulls the two outside collars against the bearing inner races, leaving the left fork leg to find its own natural position with calipers fitted and the fork pumping procedure carried out, then left pinch bolt/s tightened.

If everything is done correctly, the clearances of the disc rotor to the caliper body (not the pads) both sides of each disc should be symmetrical.

 

[eastbowl2]

Good explanation Grum, thanks. 

[Wald]

On 5/20/2022 at 2:24 AM, Grum said:

The left fork shouldn't be forced to a position it doesn't want to be just to ensure the axle is flush to the fork, this might create a bias to one side of the left disc rotor potentially causing your issue.

In addition, you do not want to find out what the front will do at 150 mph. Every misalignment and tension multiplies with speed.