Front Brake Warped

[theparras]

Just wondering if anybody has experienced problems with there front brake disks warping. I have a mate who's trx has R1 calipers & disks which were on there when he brought it, this leading me to belive there maybe a problem with the trx brakes. With mine when I apply the brakes I get a shuttering feel from the front end. I was thinking of running a dial indcator on the disks to find the high spot then use a rubber malet to try flaten it or just grind the high spot down not sure yet.

[idl1975]

Just wondering if anybody has experienced problems with there front brake disks warping. I have a mate who's trx has R1 calipers & disks which were on there when he brought it, this leading me to belive there maybe a problem with the trx brakes. With mine when I apply the brakes I get a shuttering feel from the front end. I was thinking of running a dial indcator on the disks to find the high spot then use a rubber malet to try flaten it or just grind the high spot down not sure yet.

The R1 brakes are on there because they're better. But yes, it's a recognised problem, and is most probably related either to the pad compound of the original Sumitomos or to contamination of the calipers and sticking pistons (more likely, IMHO). I'm ready to be corrected, but while one may generally regrind discs on shiteboxes, I don't think it's an option on modern motorcycles with thin, drilled discs and not a lot of permissible wear.

A rubber mallet is really not going to do a lot. Try removing the calipers, pulling the pads, cleaning both calipers very carefully with brake cleaner, toothbrush and rags, and confirming that none of the pistons are stuck. Then clean the discs, scour to remove excess pad deposition and clean again. You may want to replace the pads.

If you have a seized or sticking piston, don't bother reconditioning the caliper. Pick up some blue spot calipers (preferably with the matching master cylinder) and sell the old ones on e-bay, since this will cost you just as much as fixing the caliper and is actually less time consuming.

[theparras]

the blue spot calipers are they the same as the R1 calipers, because I always see R1's in the wreaking sections of mags & might try snap up the disks as well.
Thanks for the advice.

[phuk72]

R1 calipers are commonly refered to as blue spots (for obvious reasons). They were standard fitment to a number of bikes (R1, R6, thunderace etc) and bolt stright onto the TRX and offer improved braking.

R1 discs are NOT the same as TRX discs

From what you have described, the discs are probably warped (although it could be something else). If they are warped, a rubber mallet aint gonna do a thing.

[theparras]

Yeh your pobably right about the mallet & it is a bit bodgey with the grinder to, I was just hoping to save a few dollars. I was told I need to change the pads when I do the disks. Got quoted about $300 for a disk & $50 for the pads.

[idl1975]

Yeh your pobably right about the mallet & it is a bit bodgey with the grinder to, I was just hoping to save a few dollars. I was told I need to change the pads when I do the disks. Got quoted about $300 for a disk & $50 for the pads.

As far as saving money, that's why I was suggesting that these symptoms - especially if you can't see a visible warp after looking closely at the disc - can be caused by caliper contamination and/or unusual deposition of brake pad material on the discs, especially with the original grey calipers which are _very_ prone to seizing and sticking.

So if you clean the hell out of everything first and replace the pads, you may well find that the problem is solved. If it isn't, the calipers will be clean when you put them on e-bay!

If you do end up having to replace the discs, it's worth spending the extra A$100 finding the R1 (or YZF-600R, or R6) calipers from a breaker or on e-bay because, from my experience, they are much more resistant to this problem. If you want to save money, you can use the original TRX master cylinder instead of getting the smaller one from the R1/YZF/R6.

[Quan-Time]

i had a really warped disk on a bike once. I did manage to straighten it. If it happened again, id just buy a brand new, top of the line, uber expensive new one.

yes, thats how much it sucked to straighten, its SOOO not worth it..

[Wombat]

Plus, are'nt TRX discs close to 300mm dia and R1 / 6 320mm?

Bob