Yamaha TRX850 Enthusiasts Forum

Hi all,

I've searched far & wide and can't find anything written about this.

I've installed YZF-R6 blue spots on my TRX with braided hoses. Still using the stock Nissin 5/8 brake cylinder though. After checking all pots are moving freely (haven't re-built) and sanding the disc and pads and venting about 3x I still have an issue. The brakes grip great and really work for the 1st 3/4 of the braking manoeuvre. Then they start to fade. My hunch is, that it is either air in the brake cylinder (because that's probably the only spot left for air to be in) or it's because I'm not using the right 14mm brake cylinder. Maybe someone knows this phenomenon and can help me here. I have a 14mm cylinder that I could buy but before dishing out $$$ I'd like to know if it would fix my problem.

Cheers all
Oliver

So are they the brake pads that came with the calliper? If so who knows what they have been thro. Do yourself a favour and purchase some new ones to start if you m/c was working fine before with your previous callipers I can't see that being the problem.

It could be that the problem was there before and just hidden by the crappy callipers before. They were quite bad. So I couldn't say 100% sure. But thanks for the tip.

I've got a similar set up on my bike: standard master cylinder; braided lines; and YZF (not R6) calipers,

and I do not experience fading issues.

Do yourself a favour and track down some "Sumitomo" brake pads.

These will give you great feel and no fading issues.

If there are still issues after you have installed these pads then you will have to dig a little deeper.

cheers

Fluro

Are the braked fading or are you losing pressure?

Fading is when you have a normal feel to the lever but the brake performance "fades" due to pads overheating/glazed/contaminated. If the lever is losing pressure then air is trapped somewhere or it's bypassing the master cylinder seal.

The best and quickest way to bleed brakes is to vacuum bleed them with a Mityvac pump or similar

Have you checked to make sure all the unions are sealing properly and the calipers are not leaking slightly?
sounds to me like there is an issue with the rubber seals somewhere in the system,..
http://www.google.co.uk/imgres?um=1&hl= ... 1,s:0,i:76

If you are applying an equal squeeze through the lever and the performance fades then the only thing changing is that the pads are getting hotter.
So I would go for knackered pads and spend money on new ones first.
Also bleed the system again, pull the leaver back to the bars and leave it over night, check all banjo bolts are tight etc.

I don't know alot on blue spots or masters, I run the standard set up. But I highly reccomend ferodo sintergrip road pads to try, I like these much better than the ebc ( which just went off, only half worn) must of glazed. Great feel, and great stopping power even in the standard brakes. Cheaper too, but if your unsure get a mechanic to check, won't cost too much, and a safety feature such as brakes usually come in handy

@dandywarhol: The pressure on the grip is holding so I guess that excludes air. One of those reverse pumps is nice though.

Deffo a pad/disc contamination then - as others have said.......................

Hi all,

Fitted the 14mm brake cylinder and the breaks work great. Will do the pads too just to make sure but it looks like there are EBC on them already.

Cheers Oliver

olivernz wrote:Hi all,

Fitted the 14mm brake cylinder and the breaks work great. Will do the pads too just to make sure but it looks like there are EBC on them already.

Cheers Oliver

Just because there EBC doesn't mean anything they glaze over and get contaminated, I changed mine, (because I thought they was cheap ones, turned out they was ebc hh and not even half worn) and before they was even bedded in to the old disc felt much better. I've just done a track day at mallory and couldn't be any more pleased with the ferodo sintergrip pads. So much better. Didn't overheat, disc is a dull colour and not shiney how it was with the others.

olivernz wrote:@dandywarhol: The pressure on the grip is holding so I guess that excludes air. One of those reverse pumps is nice though.

Actually that excludes a leakage problem, not air.
Air in the system is felt by a "spongy" lever with little "Feel" to the action.

I took the statement "pressure at the grip" as the system was not "spongy".
Therefore there's no air in the system to cause the grip to be spongy.

Bit like a hard on Full of fluid and no air gap and as for blue spots