[keitha]

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Mark, I thought I had similar issues, to start with on my 748r. Turned out I also had a dud front tyre. Sorted that first. So with new tyre on and on the new surface of the M1 you could still feel a vibration at 80-90kph. Back to workshop, front wheel on stand and set up a dial wheel. Over 60 degrees of rotation had 1 to 1.5 mm "play" in rotor.
Rotor off to planet... sorted. I put a new set of pads in as well, the EBC ones. I'm getting the pulsating now. Have 4000 kms since this. I will do the cleaning treatment once back in Melbourne. PM me if you want to check the rotor "play". I'm back at the Ski and Bike shop from monday week
Keith

[Slower than you]

Originally Posted by brettc63

How does that go with the full floaters? No problems?

Sorry for the late response. No problem with floaters as under the disc and against the drill press table, I supported the disc on about six thick washers. This lifts the disc a bit so the buttons don''t hit the table therefore the disc is well supported around the diameter.

The hold down bolts go through the table slots and use rubber pads on the centre hub to act as a nice cushy spring to hold the disc in place. Also to not scratch things up.

If your drill press table is perfectly perpendicular to the spindle like it should be, you'll notice that the inside of the disc will start to show sanding marks before the outer diameter will. This is as discs wear more near the outer diameter than the inner due to the surface speed that the pads see. This coning wear is normal and can't be removed with a rotor hone. All we can do with the hone is to grind off the high spots that were created with use and to remove pad buildup.

So make a few revolutions with the hone and stop. If it's pronounced that the sanding is toward the inside, tilt the table a bit until the hone works on the whole surface.

[madmortimer]

200klm today....same problem, Rotors off and some machining should fix the problem. :-(

Mark

[madmortimer]

Ah Hah! Turns out it's Headstem bearings, loose or worn, or rust contaminated that cause the pulsing in the front end.
Under hard braking it is not noticable because of the bikes weight placing pressure on the headstem bearings, negating movement.
Strip down next week. Told it's usually due at 20k.
Keith maybe thats your problem? It had me beat?

Mark

[STANLEY]

Either your description is way off or someone is taking you for a ride digger.

Dave Ward
Moto Italia
Aprilia-Ducati-Moto Guzzi
0432 441 985

[brettc63]

Originally Posted by madmortimer

Ah Hah! Turns out it's Headstem bearings, loose or worn, or rust contaminated that cause the pulsing in the front end.
Under hard braking it is not noticable because of the bikes weight placing pressure on the headstem bearings, negating movement.
Strip down next week. Told it's usually due at 20k.
Keith maybe thats your problem? It had me beat?

Mark

Good news - I've always wondered how you could actually warp those discs anyway unless you were really abusing them on a track or physically damaging them with some kind of contact.

[madmortimer]

How so Dave? My blokes seen a few worn headstem bearings but not many instances of warped rotors.
I'm all ears as this conundrum is confusing me.

Hard braking no problem, slowing under constant lighter braking pressure...pulsing! New front brake master cylinder fittted.

Mark

[STANLEY]

Bearings should be re-greased at 20k.
I have never seen steering head bearings wear out. I have seen poorly serviced bikes have the steering head bearing rusted (some beyond belief) due to never being greased from new. It is part of all service maintenance schedules.
I have seen plenty of rotors warped & replaced under warranty though.
Let him have a go & see what it does???

Dave Ward
Moto Italia
Aprilia-Ducati-Moto Guzzi
0432 441 985

[madmortimer]

Thanks for your input Dave, I'm going to let Rob diagnose my prob.
Hes a keen Ducati owner and Tech of many years, he's also the current Victorian Interclub Road Racing Series Supermono Champion rider and was also asked to take part with MV Agusta at the IOM in 2007 for their return to racing after 35 years. He's also worked with Kawasaki there.
The upshot is I do not know a better man in my area to see to my machine.
Here's hopeing.

Mark

[pat1098]

Originally Posted by STANLEY

Bearings should be re-greased at 20k.
I have never seen steering head bearings wear out. I have seen poorly serviced bikes have the steering head bearing rusted (some beyond belief) due to never being greased from new. It is part of all service maintenance schedules.
I have seen plenty of rotors warped & replaced under warranty though.
Let him have a go & see what it does???

Dave Ward
Moto Italia
Aprilia-Ducati-Moto Guzzi
0432 441 985

I have replaced countless steering head bearings on the older tapered (Timken-type) bearings. They get notched in the straight-ahead position from not being adjusted up, as well as those with water/rust effect.
Seems to be less of a problem on the later ball-type races - may be just a matter of time?