Front Brake / Bobbin Maintenance

[shadowknows977]

Igofar always writes about cleaning these bobbins. Now here's a video for the visual learners.

 

[Obo]

I had no idea those moved or were supposed to.

I thought it was just a welded or bolted or some other fastened transition from the outer ring to the inner section.

Now I'll have to check and clean.

 

[Kevcules]

I had no idea those moved or were supposed to.

I thought it was just a welded or bolted or some other fastened transition from the outer ring to the inner section.

Now I'll have to check and clean.

I'll let you clean mine if you make it to NB sometime......Since you will be experienced at it. HaHa

 

[Obo]

I'll let you clean mine if you make it to NB sometime......Since you will be experienced at it. HaHa

You coming to WoodSToc?

 

[Andrew Shadow]

I had no idea those moved or were supposed to.

Those are what make them free-floating discs.
I just use isopropyl alcohol, much cheaper, much less toxic to breathe, evaporates away in no time and works just as well for this purpose.

 

[Obo]

I didn't know we had free floating disks

I don't even know if mine have play in them, but I'm guessing they do not.

Had I noticed play in them I'd likely have thought there was a problem with them.

 

[wjbertrand]

Those bobbins (on road bikes) are mostly intended to allow the disk to expand radially without distorting when they get hot. As the ST1300 has single action sliding calipers that self align on their caliper pins, they aren't primarily intended for alignment to the caliper. I doubt cleaning or maintaining them has much if any effect on performance.

How floating rotors solved the biggest issue in braking - RevZilla

What are floating rotors, and why are they better than solid rotors? We explain the differences between the two common styles of motorcycle disc brakes.

www.revzilla.com

 

[Igofar]

Don't believe everything you think
Here, is this easier?

A Day At The OCD Spa | ST1300-Brakes

Now,, in the 4th photo down,,, is that a setup for loosening and lubricating the what-cha-ma-call-it's that allow the rotors to properly float ?? Yes. Tighten the buttons on the rotor between a bolt of the largest diameter that will fit in and a nut. Tighten it just enough so that the button...

www.st-owners.com

Read post #28 and 30.
Jul 7, 2022

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• #30

I jumped on the rotor button service today. They were good and seized however never felt that the braking was notchy or vibrating from applying the front brake. That being said, I did feel like my front brakes were grabby at the slightest touch and caused the front end to dive quickly.

Now to the service. Poor setup meant this was a tedious task (no lift). Degreaser and brake clean for each button made the buttons move under ratcheting action but in no way shape or form was I able to get any of them to spin under finger pressure after the service but they were at least un-seized and moving.

Test ride produced some astonishing results. I wasn’t expecting much because I couldn’t move them with my finger but my front braking significantly improved.
First, no more grabby brake. Just a nice smooth gripping of the rotor which leads to:

Second, no more abrupt diving at slow or high speed which means more control on the front end and overall on the bike. Huge safety win there!!
_______________________________________________________________________________________________________________

Jul 4, 2022

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• #28

Esti1300 said:
OK, what? These are suppose to spin/turn freely? Please expand on benefits over pitfalls if these are left in a seized position. Inquiring minds want to know…
What size bolt-nut combo does the trick?
Thanks

Yes they should be able to spin with finger pressure.
Your rotors should float, allowing everything to work smoothly together.
When brake dust or rust seizes them up, the rotor can cause vibrations or front end wobble etc.
A couple Kawasaki police motors had wobble’s and front end shake, the dealer replaces fork springs, fork oil and seals, bushings, front wheel bearings, steering stem bearings, balances the tires, and finally replaced the tires….all without fixing the issue.
The officers brought me the bikes, and 10 minutes later both bikes were almost as smooth as an ST
Sometimes just paying attention to the small details makes a big difference.
It’s just the OCD in me

 

[dduelin]

If you don’t have “grabby front brakes” or “vibrations or front end wobble” it’s a bunch of hoowie. There is no objective or scientific reason this service is necessary when there are no symptoms. Lots of motorcycles have solidly mounted rotors and practically every car or truck has solid rotors. Unless there is pulsing or vibration under braking the calipers are in alignment and/or able to handle minor runout.

 

[Igofar]

You may want to re-read the first three lines of the post again….
This guy didn’t think anything was wrong with his bike (common) but was very surprised at the difference once he did it.
Perhaps you should take 10 minutes and check or clean yours to see if notice a difference before discrediting my comment as hoowie with no experience in trying or doing this service.

 

[dduelin]

Actually you should reread it and note the grabby brakes symptom noted before the service and the fork dive mentioned later.

2 of my 3 motorcycles has solid mounted rotors. The one closest to the ST in design outbrakes the ST 70 mph to 0 by 23 feet. The one with floating rotors doesn’t have grabby brakes, front end wobbles or vibrations. It doesn’t need fork service to fix abrupt front end dive at slow or high speed.

 

[Obo]

Well I checked a few of mine mine tonight and did the bolt through the hole method and they moved, but squealed something awful. No finger movement. It's been added to the list.

@Igofar might whisper but I tend to curse. lol

 

[gmtech94]

This was a normal service on our VFR and CBR race bikes . The crud build up was pretty impressive after a weekend . Never had too much difference in braking unless some one forgot to clean these up .

 

[wjbertrand]

If you don’t have “grabby front brakes” or “vibrations or front end wobble” it’s a bunch of hoowie. There is no objective or scientific reason this service is necessary when there are no symptoms. Lots of motorcycles have solidly mounted rotors and practically every car or truck has solid rotors. Unless there is pulsing or vibration under braking the calipers are in alignment and/or able to handle minor runout.

This! And even then the problem probably lies elsewhere, at least that's been my experience. I had to have both front rotors replaced on my ST1300 under warranty due to pulsing. Turned out one of the rotors had an inconsistency in thickness. The bike was too new (less than 3000 miles) for the bobbins to be involved. I also had to have the front rotors replaced on my Super Tenere due to low speed pulsing. This happened at higher mileage than the ST so I fiddled with the bobbins. They were hard to move, but were movable with some effort. No amount of fiddling changed anything, either in the tightness of the bobbins or the pulsing behavior of the brakes. That's when I turned to Yamaha for warranty. Their conclusion was improper machining, but never elaborated. The replacement rotors have been fine from new and now 65,000+ miles later they're still fine. I've never messed with the bobbins again.