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Life is too short to worry !
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Having now sorted my oil light problem I now need to decide what to do with my front rotors.

I have found a source for new bobbins but I seem to recall reading that the rotor mounts on the ST4s are aluminium ?
If this is the case then I wonder whether it will be the mounts that have worn and not the bobbins giving me the excess run-out that I have.
The discs themselves are still well within tolerance for thickness after 48,000 Mls and I dont have any pulsing problem to worry about after a recent good cleaning sesssion but I have been pre-warned that they wont pass the next MOT Test so I will need to do something.

I dont want to spend money on a whole set bobbins only to find they are unable to sort the problem.

Anybody done this fix ?
 

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I have changed two sets of "snowflake" rotors to full floaters with replacement buttons. First set I had was on my old SS. I used the STM 5MM kit and found it was a very loose fit. I ended up buying a pack of thicker washers to make up some of the slop. For the second set (on the ST), I used the TPO kit. The fit is perfect on the 4.5MM snowflakes. Almost no brake drag (main reason for this mod) and by my fish scale / belt tension tool, you drop just under .5lbs between the two rotors.

Very doubtful your aluminum carriers are too worn out to do this. Even after many miles of use with the sloppy fit STM rotor buttons, the carriers of that first set I converted did not show excessive wear when took them apart to put the thicker washers on. Keep in mind that with the stock tight-fit buttons, you have very little movement between the rotor and carrier. With the floaters, you have a lot of movement. Takes some getting used to, in fact! Point is your carriers are likely fine. This is a good mod. Just be ready for the extra noise.
 

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TPO for me

Hello
I, too, have done the TPO buttons on my sT with just under 60K miles on the clock. They seemed to fit fine, just "loose enough".
I've noticed no wear, but replacement carriers are plentiful if it does show up.
 

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disc rotor repair

Gearbox,I to am from Scotland,Cheers from Colorado!My question is,I just purchased a 02 SR4s,and the rotors are warped,rather than spend hundreds of dollars for new rotors,can they be reground back to tolerences.Its done every day for autos?Thanks,David
 

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Gearbox. I dont want to hijack this thread but I am also from Scotland. My Dad was born near Peterhead in 1921 and my last name is Duguid.
I dont miss the MOT here in the states it makes it easier to customize your bike.

Desmo dave look on ebay its probably the cheapest way to go.
 

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Life is too short to worry !
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Discussion Starter #6
Gearbox,I to am from Scotland,Cheers from Colorado!My question is,I just purchased a 02 SR4s,and the rotors are warped,rather than spend hundreds of dollars for new rotors,can they be reground back to tolerences.Its done every day for autos?Thanks,David
Hi - If you do a search you will find many suggestions as to other causes to brake problems that only infrequently are rooted in warped discs.
Mainly sticky bobbins or brake pad residue.
A good clean (if available with a glass bead blaster) and a good clean out of the bobbins with liberal use of brake cleaner usually does the job.
Regarding machining (if that is the problem) - I doubt it is possible because whereas brake discs have a lot of material to skim the brembo discs only start at 5mm and the minimum wear tolerance is 4.5mm so not a lot to work with (others who know different amy choose to comment)

I think I shall wait until the off-season and dismantle the discs to see where the wear has taken place (Aluminium mount or bobbins) and then either order a full set of bobbins or order new discs (Galfer seem popular ?)

BTW - Not to mislead anybody - Although living Scotland for nearly 13 years -I am from Essex originally but chose this area due to the friendliness of the people and access to the beautiful scenery after many holiday visits.
It is a very under-rated area with terrific cliffs and beaches , fantastic clear roads and only a few hours from the Highlands.
 

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Thanks for the reply guys,After three good scourings with S100 and a brush it solved the shuddering problem.I just did a 100 miler up and down the canyon and Walla ,Perfect,Cheers Dav
 

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Och Gearbox yer a Sassenach!

I understand your move I feel the same way about Alabama but the difference is that I can ride all year long without worrying about salt and ice.
 

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Discussion Starter #9
Och Gearbox yer a Sassenach!

I understand your move I feel the same way about Alabama but the difference is that I can ride all year long without worrying about salt and ice.
You forgot the wind ! :D
But we do have the best whiskie's.;)
 

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You forgot the wind ! :D
But we do have the best whiskie's.;)
Whiskie's yes Whiskey, there are people in Kentucky who would argue:)
 

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Gearbox you are right about the whisky thats why I always have a bottle of Bells within arms reach.(when i am not riding or driving). In fact I will be in Haddington, just outside Edinburgh in 5 weeks at a wedding and I will be reminding myself of my homeland by sampling as many different types of Scotch as can.
 

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brake disc resurfacing

Gearbox,I to am from Scotland,Cheers from Colorado!My question is,I just purchased a 02 SR4s,and the rotors are warped,rather than spend hundreds of dollars for new rotors,can they be reground back to tolerences.Its done every day for autos?Thanks,David
I see your problems are solved now, but in the interest of new eyes on this thread....

This Michigan based business was recommended to me with enthusiasm by a friend of a friend. I have not used them, and am unsure of their practicality on performance applications, but it seems a route I may try when the time comes.
TrueDisk LLC - Motorcycle Brake Rotor Resurfacing and Grinding Services

PS: I'm not from Scotland, only Scot blood :)
 

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I went for the Corse Dynamics full floating 5mm kit for my bike three weeks ago and yes they are loose but perform flawlesly (spelling). I have one slightly warped rotor but I will regrind it flat maybe over the next couple of weeks. The full floating buttons take away the pulse but they are a bit loose. Might try adding a washer :)
 

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I always thought the bobbins were pressed on? Do you have any pics of the ones you fitted? Just curious!

John
 

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Life is too short to worry !
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Discussion Starter #18
Well I'm a Scot living in Scotland :D
Alan, on what grounds does your MOT man say they won't pass next year. If they meet the efficiency requirements (it would be hard not to), they are above the minimum thickness and there is no fluctuation in the braking performance (warped discs) on the rolling road tester then there are no grounds to fail.
From the testers manual: MOT UK car and vehicle MOT information equipment car servicing parts and spares - hand brake control valves
Hi Derek - This must be one of the oldest revived threads......

The problem was on my old '02 and the failure would have been because there was too much rotational play (i.e. you could turn the disk because there was too much play) I eventually got so close to the thickness tolerance that it was pointless replacing the bobbins and just fitted Galfer discs and pads which was able to transfer over to the new bike.

Problem with updating the Avatar is that it appears to update retro-actively which can cause some confusion.
 

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Ah, thanks for that! I take it you have to grind the old bobbins off?

John
 
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