Replacement Discs for 1200 Sport

[JAS]

Hi all:

Like others, I am having problems with the front discs (right disc actually) on my 1200 sport, shudderring, especially at high speed. I have freed up the bobbins etc (kept them free since 3000km, now have 9500km) with no change. The right disc has significant runout and has variations of up to 1.5 thou over the disc surface (left disc only 0.5 thou).

I am going to try a warranty claim, but from other people's experieces, am not hopeful.

As floating discs can't be reground and I can't put up with this shudderring problem, looks like disc replacement is the only way to go.

I had thought of going after market, and looked at EBC discs. Not sure if it is an exchange rate problem or something else, but I priced the discs with new pads here in Australia, and they are incredibly expensive. Looking at about $1000 for the lot.

I was wondering, does anybody know (or know where to find out) what specific model of bikes have the same discs as the Breva 1100? I have not heard of any problems with the Breva's discs, and the Breva shares the same front end (as far as I can tell) as the 1200 sport. Discs must be interchangeable?

I was thinking if Ducatis / Aprilias / Japanese bikes etc share the same discs (or disc diameter, offset and bolt pattern), I should be able to get a pair form the wrecker at a more reasonable price. I don't care about the wave disc pattern, just want something that works and doesn't vibrate.

Any ideas?

Thanks,

Jason

 

[Roblatt]

Jason,

Get the warranty claim in ASAP. No more warranty on disks once you exceed 10,000km here in Oz, irrespective of how much warranty time is left on the bike!

I know, it happened to me!

Robert

 

[Mike.C]

You can get aftermarket ones from Metal Gear here in Aus. if your warranty claim is a no show.

LINK HERE

 

[JAS]

Thanks Robert, I will put a claim in next week. The anti friction coating on my forks has worn away, I don't really care about this but if MG won't come to the party on the disc, I might have second thoughts. Surely must cost more to replace two forks rather than a single disc?

What excuse did they give on the discs? Did you make a complaint through NSW fair trading? I've read the Waranty book, can't see how they can get out of it.

Mike, I have found a distributor for Metal Gear discs near my home, and will call them next week, but not sure how much cheaper they would be than EBC. Worth a try, will see.

Jason

 

[Roblatt]

Jason,

I was unaware about the km limitations. My dealer kept telling me a little pulsating was normal - until I'd reached 20,000km, then he said the left rotor was warped. Of course he didn't remember all my previous comments so it was my word against his. I've since found out that MG doesn't pay well on warranty work so dealers prefer clients to pay!

I contacted John Sample, the importers, who after muuuuuuch arguing and discussion agreed to supply new disks if I paid for the install. Well, they won because I got sick of chasing them and nearly a year later, still no disks. So, I'm doing my bit and telling anyone that cares to listen "if you want Italian V twin power - buy Ducati".

I love the bike and with the aid of the good people on this site, am now learning to do my own work as I've lost faith in the Oz network of approved repairers. Give me a few years and I may learn some of the stuff that others on the forum have already forgotten.

Gees, this is sounding like a whinge. Anyway, I feel better now. But get in quick and keep a copy of the list of defaults you give the dealer and let him know you have the copy.


I hope you have better success than me buddy.


Robert

 

[GrahamNZ]

Jas
A lot has been posted about brake juddering problems on Brevas, so you're not alone. A search might be useful for those.

1.5 thou runout is insignificant on a semi-floating disc. Tight bobbins can be an issue but so also can be brake pad deposit buildup on the discs. That can be caused by poor pad material choice or by not enough hard applications. Going to harder pads is often the perfect cure. I couldn't tell if one disc was juddering more than its partner.

Juddering at higher speeds can also be caused by loose or worn steering head bearings. Pulling wheelies is a common cause of bearing troubles but somehow I've never managed on on my Breva! Maybe a 1200 Sport will though?

Graham

 

[JAS]

Robert, yes I have heard this sort of thing from a couple of people, and Guzzi wonders why they have new models but can't sell properly???????

I can't put up with this vibration, so if I have no luck with the distributors, I'll probably try a set of sintered pads and see if this improved things, if not I'll try and get a set of discs from a late model Duck or Aprillia.

Graham: I was not aware that Bravas had major troubles (I had seen a few owners have problems), I had already checked out a few pages on Brevas & Grisos, but had the impression that they didn't have the widespread problems of the Sport. I loosened the bobbins up when the bike had 3000kms up and shamfered the pads which improved the shudderring, unfortunately by then I think the damage was done.

Perhaps my original post was unclear, I meant 1.5 thou disc thickness variation over the disc, not runout, which is pretty significant (I have an article which indiactes anything more than 1 thou will be felt). I didn't measure disc runout as the holes in the disc made it too difficult to run a dial indicator. They are floating discs so I am not sure how relevant disc runout is anyway? The right discs has significant runout (compared to the left disc), as the disc rubs in two areas diametrically opposite (when the wheel is rotated), whilst the left disc has no uneven pad friction.

I think that the bobbibs from the factory are too tight, they seized, the disc could not "float" and warped, I freed them up when I noticed a problem, but by then it was too late. Most 1200 Sports I think have the same problem.

Thanks for your response,

Jason

 

[john zibell]

I'm sure Todd will be glad to set you up with good rotors and pads. See https://www.guzzitech.com/store/Brembo-Store.html

 

[azccj]

The front rotors on my Norge started pulsating within 2k miles and got worse over time. Both were replaced under warranty without any problem. When the new rotors went on I also replaced the front pads, using EBC sintered pads. In 5k miles I've had no more problems with front brake pulsation. While waiting for the replacement warranty rotors I read several online articles about brake pulsation. One author claimed there is no such thing as warped rotors and the pulsation you feel is the buildup of pad material on the disk. Another author claimed that he resolved his motorcycle brake pulsation problem by switching to sintered pads and after several hard high speed stops the problem was fixed, presumably by the more abrasive sintered pads removing the pad material deposited on the rotors. I myself have only had pulsating brakes on two of my more than 20+ bikes that I have owned over the years. Both those bikes were Guzzis, my Norge and a new 2003 LeMans. Both of those bikes started developing the problem within 2k miles from new and I was never that hard on ethers brakes to develop the kind of heat needed to warp the rotors. If I was racing the bikes around the track, maybe but most of my driving is highway touring miles. I myself believe the problem is caused by the pads which Guzzi puts on the bikes at the factory, maybe the pad material is too soft.

But if Guzzi wont warranty the rotors, before I'd spend the $500.00 out of my own pocket it would cost to replace them, I would first try switching to sintered pads and see if that doesn't improve or eliminate the problem. And even if Guzzi or you replace the rotors I would still switch out the pads.

 

[GrahamNZ]

azccj

Bull's eye! I am probably one of the authors you refer to in not believing that discs on road bikes often warp but that unsuitable pad material is often the cause of juddering.

In my case the slow speed juddering with my Breva was cured after loosening the very tight bobbins (rivets) and then using the brakes hard every time I ride. Brakes revel in hard excercise, like most things. The runout on my discs was negligable by the way, and I'm still using the stock pads.

Buell until recently fitted fairly soft pads to that huge front brake and pad material transfer was a real problem. Mine suffered from it but was cured completely by fitting harder sintered pads. The downside is that initial bite is reduced, more pressure is required and disc wear is increased. Incidentally, Buell allow up to a whopping 0.8mm runout on the disc because it is floating.

Ducatis and Aprilias aren't immune from the problem either.

Maybe it's journalists who are largely to blame for praising brakes which require only one or two finger operation that encourages manufacturers to fit soft pads to achieve that. Personally I use all four fingers on the front brake and from watching film of Rossi in action, so does he. Using all fingers all the time ensures that come emergency stopping time you will automatically be ready for the full Monty. Four fingers also provide greater pressure control.

So my advice is to ensure bobbins are loose enough to allow the discs to move as they should, to fit harder pads to clear the discs of pad impregnation, to use the brakes hard every time you ride, and to use four finger application.

Graham

 

[JAS]

I read the paper on uneven disc pad deposits on the disc, thats the reason I measured the thickness of the disc at different points and found the variation of 1.5thou.

Already looking at buying just one set of sintered pads, installing them on the right problem disc and seeing how it goes. As azccj observed, this seems the cheapest way to try a fix. If it works, I'll buy a pair for the left caliper as well, ditto if I get the disc changed under warranty.

I think the front brakes on the guzzi are too sensitive at low speed anyway, so I would welcome a bit more lever pressure.

Anyway, I'll see how it goes, thanks for the advice.

Jason

 

[Greg Field]

JAS:

Does your 1200 Sport have the Braking wave rotors or Brembos?

Sintered pads do not require more lever pressure. They require less. EBCs do, at least.