How do you know if you have the 14 or 16mm Master Cylinder on an '06??

[ELP_JC]

Hey SR1, so you're saying the problem emerges with use? That's interesting. What the hell happens then? Without external leaks, it can't be anything else other than internal M/C leak, right? I ride around 4K a year on my sport-tourer, mostly highway. My BMW has 15K miles, and brake pads are almost like new still. The equivalent of a lot less miles in the city.
I don't like the idea of iffy brakes at all, especially when I use 2 fingers all the time, and if I hit my fingers maxing out my braking at that point, it could mean an unnecessary accident. Not a pleasant thought.
I'll have to weigh all the pros and cons, and choose between this bike and the VFR. Cost is a wash between new '06s. And even '07s, I believe. I don't like the VTEC ***** on the VFR, and the smallish engine, but both the VFR and ST have very similar flat out performance, but I obviously prefer the torque of the ST. I also don't like the cable clutch of the ST, but can live with it. Don't like chain on either one, but that's what I need on a lighter bike, and am willing to live with it. As far as drivetrain reliability, the Honda is probably better, but haven't searched much. Not worry about it too much.
JC

[SR1]

The best guess of the problem is the pistons in the calipers. They get stuck and don't move all together. I think this is mainly due to dirt, but other bikes don't have the same problem due to (presumably) different seals and a coating on the pistons. While it is true I don't wash my bike much, I do clean the brakes but have found that in order to have "as new" brakes all the time you both have to exercise and clean the brakes every few thousand miles. Basically you take the calipers off, pump the brakes until the pistons come way out, flush them out with some brake cleaner, then use a big ass screwdriver (BAS) to push them all the way back into the calipers, and then, once you put the calipers back on and pump the brakes up, you'll have "as new" brakes again. It takes abotu 10 minutes. It's pretty apparent when you have the caliper in your hand and pump the brake lever...the pistons never move together and one is usually very sluggish. You need to make sure that the "lively" piston hits something solid so that the sluggish one will be forced to start moving. Once you've gotten them all moving again good braking is restored.

If you don't ride a ton, you probably won't notice as much. Exercise them once every 6 months or so, I guess.

FWIW if the 07's have gotten different seals and coated pistons, they may be alright, but we've heard nothing of it.

[ This message was edited by: SR1 on 2007-06-04 21:13 ]

[86gn]

The "fix" seems to be changing the m/c to the 5/8 and change the pistons to the ones from the 675 if you want to stay with Triumph stuff.

[CLB]

On 2007-06-04 21:10, SR1 wrote:
The best guess of the problem is the pistons in the calipers. They get stuck and don't move all together. I think this is mainly due to dirt, but other bikes don't have the same problem due to (presumably) different seals and a coating on the pistons. While it is true I don't wash my bike much, I do clean the brakes but have found that in order to have "as new" brakes all the time you both have to exercise and clean the brakes every few thousand miles. Basically you take the calipers off, pump the brakes until the pistons come way out, flush them out with some brake cleaner, then use a big ass screwdriver (BAS) to push them all the way back into the calipers, and then, once you put the calipers back on and pump the brakes up, you'll have "as new" brakes again. It takes abotu 10 minutes. It's pretty apparent when you have the caliper in your hand and pump the brake lever...the pistons never move together and one is usually very sluggish. You need to make sure that the "lively" piston hits something solid so that the sluggish one will be forced to start moving. Once you've gotten them all moving again good braking is restored.

If you don't ride a ton, you probably won't notice as much. Exercise them once every 6 months or so, I guess.

FWIW if the 07's have gotten different seals and coated pistons, they may be alright, but we've heard nothing of it.

Yabut...
To be fair, that will be the case with any multi piston caliper.
With the pads removed or backed off, the only resistance to motion the pistons have is the static friction of the seals. I can pretty much guarantee you that the static friction of the seals will never *exactly* match between all pistons in any caliper.
When you squeeze the lever, pressure rises in the caliper.
As soon as the fluid pressure overcomes the static friction of the least stuck piston, it starts to move. Once moving the pressure drops because dynamic friction is lower than static friction.
The next loosest piston cannot move until the first piston hits a stop, pressure rises and the next lowest static friction is broken.
Repeat as needed until all pistons are up against the pad back plates.
All multi piston calipers will do that, 6 pots included.

That said...
My bike came with the 5/8" or 16mm master and my lever travel still varied with time and use. Not as much as some of yours as lever travel will be 30% more with the 14mm cylinder.
Just pushing the pistons back with the pads (no dis-assembly required) and pumping them back out would give me a temporarily firmer lever.

After reading by David_M (I think) I ordered two 675 piston-seal kits from BikeBandit and swapped them out.
The result was a firm and consistent brake lever that hasn't changed appreciably in something like 2500 miles.
I don't know how to quantify the results other than I can lock the front or lift the rear with the lever set close (4). I might pinch my fingers trying that with any behind the lever but I have worse problems at my skill level anyway.
Unlike David-M, I kept the bike.

The kits are a little cheaper from cycle-parts.com if you know the Triumph part number.
The Triumph part number is T2020465. Each caliper takes one kit. Not being an officially blessed fix, I doubt a dealer would change them out as a condition of sale.

The Busa calipers might be cheaper, cooler or better, I don't know.

Good luck with your decision. My short list also came down to the Sprint and VFR.
IMO:
The Sprint could use a TOR, tune, throttle lock and calipers. The '07 has better sorted fueling and behaves better cold.
The VFR could use more displacement, a tougher voltage regulator and a VT_ECtomy.
You'll be happy with either.
I won't offer to trade Trumpy for the VFR.

[ This message was edited by: CLB on 2007-06-04 22:59 ]

[SR1]

CLB, I completely agree that the static friction won't be exactly the same, but with stock pistons you can tell there's a lot of friction on the pistons, period. You begin to wonder "when if ever" the second piston will start to move. I'm sure the new pistons do the deal...but 2500 is not much. For the same price I will most likely just get a 6 pot unit. Time will tell if it really works or not, or if I have to replace everything for it to be right.

[ This message was edited by: SR1 on 2007-06-04 23:09 ]

[CLB]

It's just another option.

I don't see anyone complaining after the 6 pot conversion. Several on the board swear by the conversion. I may have gone that route myself had it been the first option I discovered.

But... I am not complaining (about brakes anyway) either.
As my bike stands now, hardware is not the limiting factor.

[neil1052]

I originally found the std 14mm master cylinder give too much travel.
Then after a few miles it got worse & found the brakes needed pumping up 3 or 4 times, before feel & bite returned,
I put up with this until the m/cyl was changed for a 16mm item at 14k miles, now it doesn't need pumping before riding, plus the feel is a LOT more firm ....

stuff all that ***** about designing in feeeeeeel......
my ST had about 4 times too much travel & feel under braking !

Now (with the 16mm m/cyl) my ST pulls up nearly as quick & hard as my S3, whereas with the 14mm m/cyl on the ST, on the same road & speed when on my S3 the S3 would pull up 20 or 30 feet quicker, now its only a few feet differrence !

Hope this helps, Neil.
:-D

[duckie]

I've got an '07 and I've been having problems with my brakes ever since I've got the bike although not as bad as people have described on their sprints. Every so often the lever travels closer to the handlebar and with a quick release and pull the lever doesn't travel as far - this is only about 1/2 inch difference as far as I can tell. I do a lot of miles on my bike and also use just 2 fingers to do braking yet I have had no problems with stopping very quickly even when the lever travels closer to the handlebar (never close enough to squish my fingers and I have the lever set at 4).

As yet I've been too busy / lazy to take the bike to the dealer to submit a warranty claim for it as it doesn't seem a major problem although I would like it fixed. It may just need the brakes bleeding but it sounds like the pistons getting stuck to me.

The 07's should have the 5/8 or 16mm master cylinder but I can't find any raised numbers on the master cylinder...
CLB - how much were the 675 seals? Did you just buy the seals or the coated pistons as well?

[ELP_JC]

Is there a way to find out at which VIN number the changeover to 16mm took place?
SUpposedly, every M/C has the number 14 or 5/8 stamped somewhere.
It's also clear the bigger M/C is not an absolute fix, but it's definitely an improvement. And I'd like my bike with it if I decide on the ST. I was disappointed there's no TSB, so need to find out if the 'courtesy' replacement applies to a 2nd owner or not. I'm not going to buy an '07, so I'd like to know which VINs are affected to avoid those. Or make sure I can take care of it under this 'charitable' program.
My bike is getting picked up on Saturday. I'll make up my mind by then for sure. Thanks a lot for all your great help and comments. Take care.

[SR1]

The retrofit does apply to second owners, as I am one.