Yamaha TRX850 Enthusiasts Forum

Just a quick question:

I bought a set of 6-pot R6 calipers in this excellent forum and have fitted them on my Trix instead of the blue-spots.
I do feel, however, that the blue-spots were a bit more "responsive"; in other words the brake lever feels a little bit more spongy with the 6-pots (Nooooo - there is _no_ air trapped in the braided lines....).
I hear someone say that the newer radial brake master from R6 ('05 onwards) or the R1 ('04 onwards) is much better.
Does that have anything to it?

I also bought a set of Titax levers (£125 phew) - very nice, although someone said that you had to buy a R6 front master to fit it - so I did - and it turns out that the R6 master ('03 I believe) is exactly the same as the standard Trx master... bugger.
If it turns out that I have to get a newer R6 master, then I have to buy a new Titax lever - double-bugger

Any comments?


Best regards Thomas.

The R6 was only ever fitted with 4-pot blue spots (I think) so the 6-pots are more likely to be from a YZF750. The '03 R6 master cylinders have a 14mm bore and the TRX (and the YZF750) use a 5/8" bore master cylinder. If you're using a 14mm m/c with calipers that need a 5/8" m/c that might explain the spongy feeling at the lever

Kayla wrote:The R6 was only ever fitted with 4-pot blue spots (I think) so the 6-pots are more likely to be from a YZF750. The '03 R6 master cylinders have a 14mm bore and the TRX (and the YZF750) use a 5/8" bore master cylinder. If you're using a 14mm m/c with calipers that need a 5/8" m/c that might explain the spongy feeling at the lever

Is the correct answer

FWIW (and I speak from experience) the YZF 6 pots are not worth the effort and you will need to rebuiold them if you use them in the UK on anything other than dty roads. And even when they are working well, the still aint as good as blue spots

Thanks for the answers Kayla and Phuk72.
You're right - the calipers are from a YZF750 - my mistake.
The R6 brake master is exactly the same as the original TRX - perhaps the (ebay) seller has got it wrong?

So I suppose I'll be better off changing back to the blue-spots instead of pursueing some exotic brake master that'll make wonders with my underdimensioned 6-pot calipers?

Stupid question: How come a 4 pot blue spot caliper is better than a 6 pot YZF caliper? I thought the brakepad area had everything to do with braking efficiency?????

Think `caliper rigidity` too thch.

Mincehead wrote:Think `caliper rigidity` too thch.

Is right

The R1 and R6 blue spots are machined from one block of aluminium, whereas the YZF750 calipers are two halves bolted together.

Personally, I'd fit blue spots instead of 6 pots if I had the choice. Just make sure you use the correct 14mm master cylinder

Kayla: Are u certain that the TRX is a 5/8 master cylinder and the '03 R6 is a 14 mm?
The newly bought R6 and original TRX ones I got looks identical. Where do you measure the '5/8' and 14 mm?

thch wrote:Kayla: Are u certain that the TRX is a 5/8 master cylinder and the '03 R6 is a 14 mm?
The newly bought R6 and original TRX ones I got looks identical. Where do you measure the '5/8' and 14 mm?

The internal bore

And yes, they are definitely different

thch wrote:Kayla: Are u certain that the TRX is a 5/8 master cylinder and the '03 R6 is a 14 mm?
The newly bought R6 and original TRX ones I got looks identical. Where do you measure the '5/8' and 14 mm?

There should be some numbers cast into the body of the master cylinder which give the size. The TRX/YZF ones have '5/8' and the R1/R6 ones have '14'.

I stand corrected!
Just examined the two master cylinders. The TRX is 5/8 and the R6 is 14 mm.
So the best option is to fit the R6 master cylinder with the R1 blue spots?

Thanks for the lesson

thch wrote:I stand corrected!
Just examined the two master cylinders. The TRX is 5/8 and the R6 is 14 mm.
So the best option is to fit the R6 master cylinder with the R1 blue spots?

Thanks for the lesson

That's definitely the best thing to do, they're the best brakes by far for the TRX

Thanks for the info Kayla - I'll go fit them today

Since you do a lot of stuff for the TRX, do you know if it's possible to get a hold of a set of large header pipes?
I've been scanning eBay for the last 6 months for an Over set or Akrapovic without luck.
At the Over japanese site, they refer to a dutch firm (cmsnl.com) - these are, to my understanding, a remake of the originals and very expensive.
Doesn't anyone make these larger headers in the UK?
(And if I'm going to try to get them made in Denmark, what exact diameter are the tubes?)

Regards Thomas.

thch wrote:Thanks for the info Kayla - I'll go fit them today

Since you do a lot of stuff for the TRX, do you know if it's possible to get a hold of a set of large header pipes?
I've been scanning eBay for the last 6 months for an Over set or Akrapovic without luck.
At the Over japanese site, they refer to a dutch firm (cmsnl.com) - these are, to my understanding, a remake of the originals and very expensive.
Doesn't anyone make these larger headers in the UK?
(And if I'm going to try to get them made in Denmark, what exact diameter are the tubes?)

Regards Thomas.

I was looking into it a while ago, and was going to use my bike as the pattern for a batch of 2-1 exhaust headers made by AAS up in Newcastle. They can do stainless or titanium and once they have the jig they can make them to order. I'm looking out for another (cheap!) TRX to use as a pattern for them to build a system around.

I fancy a set of big bore headers to form the basis of a 2-1-2 system, what sort of money would it cost?