Rotor/Caliper Issue

[scott_1200]

Hi!

I have a problem with the new rotors I purchased a while ago and was wonder if anyone else has seen this kind of problem or can confirm what the problem really is.

I have a 1989 FJ1200W (36,000 miles) that has been in storage for 12 years.  This last summer and fall, I have been rebuilding the bike and one of the new items I needed were rotors.  I bought some rotors off of Ebay.  The reviews were favorable and I believe other FJ'ers have used them successfully.  The new rotors are slightly larger than the stock ones.  The new rotors measure 300mm in diameter and are 5mm thick.  The stock rotors are 298mm in diameter and only 4mm thick.  Install was easy.  Since everything was apart, I had the forks redone (new oil, seals and bushings).  The wheel bearings looked good, so I left them alone.  I put everything back together and noticed that the rotor is rubbing aginst the inside of the caliper.  Both rotors are rubbing the calipers in the same spot.  It's like the down tubes have been twisted in just a little so that the one edge of the caliper hits the rotor. I installed a new axle and also found that the right fork is slightly bent. The left fork looks perfectly straight.  But no matter how much I rotate the fork, the rotor still rubs aginst the caliper.  There's no warps in the rotor and they look perfectly straight when spun (no wobble).  If I fix the front fork, will that also fix the problem and perfectly center the rotor in the caliper?  Can anyone confirm that their rotors are perfectly centered?  Are the calipers slightly twisted in as stock?  I never noticed this with the old rotors, because the smaller and thinner rotors gave enough clearance to not rub, but that doesn't mean that they were perfectly centered. I never check the old rotors and I do not have them anymore.

Any help is greatly appreciated.

Scotty

Here are some pics of the problem:
http://www.flickr.com/photos/scottmorton/6737545329/#
http://www.flickr.com/photos/scottmorton/6737545591/#
http://www.flickr.com/photos/scottmorton/6737547059/#
http://www.flickr.com/photos/scottmorton/6737549597/#
http://www.flickr.com/photos/scottmorton/6737548303/#

[moparman70]

I don't have any experience with the rotors you mention -- but just a thought and really don't know if it is feasible -- can you file down the calipers where the rotors hit

stevecc

[scott_1200]

I filed down one of the calipers just a little bit and it helped, but didn't eliminate the problem.  I know I could file it down some more with a dremel to keep the rotors from rubbing.  My main concern is if the rotors are suppose to be perfectly centered in the calipers.  If not perfectly centered, it may take longer for the new brake pads to eventually wear down enough to give full contact with the rotor.

Scotty

[flips]

Hi Scott

I'm no expert and probably totally off the mark  ....I'm sure some fj guru's will chime in...      but my thoughts none the less 
Firstly having a bent fork leg, besides probably being dangerous, is going to ware things out IE bearings/slides/seals etc.I would plan on replacing it asap.
If one fork leg is slightly bent I would guess that the whole geometry of the caliper/ rotor /wheel is going to be affected and may change as the fork lowers slide up and down depending on the orientation of the bend in the fork leg.Also the over all length of the  bent fork leg will be slightly less than the straight one.I would try orientating the bend either forward or rearwards in line with the wheel.I would remove the fender/mudguard and fork brace, loosen the triple tree clamps and try to manipulate the wheel while watching the rotor's position in relation to the caliper's.If they move to a more favourable position tighten the triple tree clamps.Again this is probably rubbish advice...wait for a guru!...but I hope this helps.

Cheers and good luck!

Jeff P

[scott_1200]

I rotated the fork several times and found the location with the least amount of rubbing.  I guess I'll have to get the fork fixed first and then see if the problem is still there. Anyone know of a place in Phoenix, AZ that and fix a slightly bent fork?

Scotty

[SlowOldGuy]

Nevermind

[racerrad8]

Scott,
       I am having trouble wrapping my head around the thought a bent for tube can cause that much of a offset in the caliper. If the right fork tube is bent then I guess it can make the axle be out of square and thus the calipers could be offset from the top to bottom.

But, with that said, the calipers will have the same issue on both sides. If the same amount of offset in the fork tube was the cause because the axle is not square and it will show in both calipers.

If you are only having an issue on the left side, then you need to look there exclusively. Did you put on new pads with the rotors, if so how was the wear characteristic of the ones you took out.

When you spin the wheel does the rotor run at the same angle of offset for the full 360*? If not, then the rotor is warped or the mounted surface is not parallel. If the rotor does not have any run-out and maintains the same distance throughout the rotation, then you need to look at the caliper mounting & caliper.

Check it out a little more and let me know, I would be interested to know if the fork tube is actually the cause of this issue.

Randy - RPM

[scott_1200]

Hi!

As I rotate the wheel with everything together, both rotors rub the same amount against their caliper, in the same spot and are at the same distances and angles in each caliper throughout the wheel's rotation. It's very symetric.  At first I thought it was a slightly bent axle so that when it was tightened, it twisted each fork the same amount. The axle turned out to be barely bent, so I replaced it, to elimenate it as being the cause.  When I tightened the new axle the problem was still there, only just a little less.  I loosened the triple clamps and the left fork tube just about slide out by its self and the right fork slide out with just a slight twist.  As I put everyting back together I rotated just the right fork in the triple clamps at 90 degree increments and saw a very slight increase between the axle hole and the wheel, maybe 3/16" at the most.  It isn't much and is probably within spec, but is the only thing I can go on right now.  I figured it wouldn't hurt to double check it.

I looked at the caliper mounting surfaces and they look nice and clean.  I thought there might be something there also.  I did give the lower tubes a good once over with some rubbing compound and then with some car wax using an orbital buffer.  I stayed away from the calipers mounts with the buffer and just cleaned those by hand. I never noticed anything abnormal.  But I'm still not ruleing those out.

The old rotors where really thin and the old brake pads seemed to have an even amount of wear on them.  But since they were a hair smaller in diameter and thinner than these new ones, they never rubbed against the calipers.  So I never thought to check if the old rotors were perfectly centered in the calipers or slightly offset like I am seeing with these.  I have already thrown away the old rotors and brake pads so I can't go back and double check.    Lesson learned:  Never throw anything away until its done.

I'm confused too.     It's exacly the same problem on each capiler.  The caliper mounting surfaces also look good and the bolts tighten up nice and don't appear to be bent.  That's why I was wondering if the slight angle of the caliper was designed that way and it works perfect with the stock size rotor, but not with a slightly oversized one (by 1mm in radius and 1mm in thickness).  I would hate to have to buy new, stock size rotors as they are very expensive and I can't return these new ones.  I'll only do it as a last resort.

The only thing I haven't thought about yet is the triple clamp, but I don't see how that would cause this kind of problem.  I am also starting to think that it might be in the wheel bearings or spacers.  I'll have to have the wheel bearings and seals replaced to know for sure.  I wouldn't think it would be those, though, because as many times as I've installed the wheel, it's never installed in exactly the same position and the problem is still there.  But, I could be wrong.

Good news is....most everything else is brand new and good to go.   And I'm really starting to like useing these smilely face things.

Scotty

[Mark Olson]

ok , so it sounds like the rotors are dragging the entire time you rotate the wheel. correct ? from the pics they are dragging with no pads in them .correct?

the rotors are larger so you need to upgrade to the blue-pot or gold -pot calipers from a r-6 or r-1 , the ones that  are not radial mount.

http://www.ebay.com/itm/YAMAHA-2006-YZF600-R6-FRONT-BRAKE-CALIPERS-w-LINES-/110812621497?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item19ccf26ab9

[scott_1200]

Hi!

The rubbing is along the entire edge of both rotors and drag the entire time you rotate the tire.  They drag against the inside of the caliper without the pads being installed.  Earlier this month, I installed new pads and rode the bike for no more than 30 miles so I could register the bike with the DMV and get the emissions test.  The pad wear on the new pads is not evenly across the entire pad, lilke I would expect and the braking feels really diminished.  I think the uneven pad wear is due to the non centerness of the calipers over the rotor.

Thank you for the ebay link.  I'm really temped to buy those to try them out.  The only thing that worries me is if after I bolt them on, they too are not centered over the rotor.  I guess I could buy the used calipers, test fit, and if not centered, put them back up on Ebay. 

Scott

[rktmanfj]

Are all the (correct) wheel spacers present?

[scott_1200]

All the wheel spacers look to be present.  I'm not positive that they are correct because they are not brand new, but from what I see in the wheel and in the schematic, they look to all be there.  I would have to have everything pressed out of the wheel and then measured to be sure.  Where can I find the measurements for the individual wheel pieces?

Scott

[craigo]

Thank you for the ebay link.  I'm really temped to buy those to try them out.  The only thing that worries me is if after I bolt them on, they too are not centered over the rotor.  I guess I could buy the used calipers, test fit, and if not centered, put them back up on Ebay. 

Scott

Scott,

If you buy these calipers, you will want to keep them and ditch the OEM ones. Add a 14mm master to them and you will have far better brakes than what you have now, even when your rubbing rotor issue is resolved.
And these are at a really nice price. I paid over $50 for my set.

CraigO

[scott_1200]

I'm running the stock wheel size and forks.  Are those calipers bolt on replacements?  Will they work for the 300mm rotor?  Sorry for all the questions and getting a bit off track from the topic.

Scott

[scott_1200]

I found a shop in the Phoenix, AZ area that can check and (if bent) straighten the forks and triple clamps.  I am going to take off the triple clamps and have everything checked this week.  I'll report back with the results.  I'll also order those calipers on Ebay if they are still available when I get home.


Scott