YZ forks, tenere brakes
 

Hi,

Could anyone who has completed this mod please help.

I have got some YZ forks to fit to my 59 plate tenere.
After looking a brake options: YZ with oversized disk is expensive to get a 320mm disk is �170.
A standard Tenere disk being 300mm i was going to try removing one disk and associated bits and run a single Tenere disk on standard wheel. After getting over the spindle size issues.

I know i will need to change the master cylinder but dont know what for? 11mm piston ???

If anyone can see any other problems with my plan please speak up.


I ride solo, very little kit and weight 80kg kitted and soaking wet.

thanks

Hi,

Think i have found the answer to my question.
Link below incase anyone else needs similar infomation.

http://vintagebrake.com/mastercylinder.htm

Cheers

Very interesting link, thank you.

What did you do with your brakes?

Hi,

I'm almost done with conversion to YZ forks. Just waiting for some inner parts of forks.
I was considering using 2 piston brake caliper but I switched to 4 piston because tenere is big bike.
In fact, pistons in Tenere calipers are the smallest ones:
Caliper cylinder inside diameter
32mm - 30mm � 1 in XT660R with Disc 298.0 � 4.5 mm
34mm - 30mm � 2 in XT660X with disc 320.0 � 4.5 mm MC - 12.7 mm
28mm - 28mm x 2 in XT660Z with Disc - 298.0 x 4.5 mm and MC - 16mm
So if you want to reuse some brake caliper I would use different ones then original Tenere. For example BMW f650GS has also just one brake caliper with 300mm disc.
Useful links:
http://www.f650gs.crossroadz.com.au/ForkUpgrades.html
http://advrider.com/index.php?thread...99113/page-271

I got a braking 320mm disk and used the original yz caliper and master. Tried Tenere caliper with YZ master but brake was very snatchy not much feel. Got an xt660x four pot caliper but would need to space the disk out slightly to allow it to clear the spokes. might try it one day though.
The pad coverage on the disk is smaller than with xt caliper but for my use its great. I know it will wear faster but not going around the world so should be fine.

Its a bit tricky to use 4 piston caliper with usual wheel, as you mentioned you need to use spacer under disc for clearance. I did that.
Good to know that original YZ brake is working ok with 320mm disc.
If I may ask which year of YZ fork have you used?
I used YZ250F 2008 and had problem with broken free pistons in cartridge.

Good info about the calipers, thanks.

My brake set up (with 48mm YZ forks/wheel) is 320mm disc, oem xtr caliper, oem master cylinder an EBC HH pads.
But I�m not happy. The braking power is good for me, but not the feeling, when braking, if I apply 20% power, it brakes 20%, but if I apply 60% power, it still brakes 20%... unless I apply more power, but then it�s all or nothing... Is this what english people call wooden brakes??

The pistons are clean, I�m going to try new pads, because it�s the less expensive.

The above "wooden" characteristics are the classic symptoms of a master cylinder that is too small a capacity/bore for the job in hand - it works but only at full pressure.

Although your caliper and master cylinder are matched (being from the original setup), the change from a 298mm to 320mm disc means more braking force is required to achieve the same level of friction. The stock master cylinder, from your description cannot meet the pressure required until it is nearly fully compressed. A larger master cylinder will give you more feel as their is a greater volume of fluid (and flow) to allow you to better control the hydraulic pressure with the lever.

Try pads with greater friction may help, but could make the "all or nothing" feel seem even worse and they may become "grabby" as well as "wooden". Worth a try though...

Ernesto, which oem MC have you used? OEM from Tenere or from XTX? It is a big difference.
I read a lot about brakes last couple months but I would still go to some good moto shop and ask them for advice because they know best what should be better for your setup and it is mostly cheaper then trying different things.
For example I have complete motomaster setup on the front but I still kind of feel that there might be some air in system because first 1cm of lever travel makes nothing. I tried bleeding it many times. Brake has got enough power - I can lock front wheel on tarmac in about 60km/h speed with full power at lever but still I think it could be better. Motomaster MC is 11mm so maybe I need 12mm or that OEM 12,7mm from XTX.

Thank you Pleiades and Falcon1651, I�m using XTR master cylinder.
What kind of MC I should use? bigger or smaller?
I have a second hand MC from an old CBR at home (with square reservoir), should I try it?

Are the XTR an XTX MC the same?

Hi,
Its a bit strange but in Haynes manual XTX and XTR MC are same 12,7mm.

If you have XTR caliper and XTR MC then I personally think changing just disc size from 298 to 320mm should not make any need to change also MC. Friend of mine changed front disc size on yz250 and he was quite happy with performance and did not have to change anything else.
Maybe piston seals in caliper might be worn so they are not moving so good.

If you have time you can try another MC from that CBR but it will be around size of Tenere MC because CBR had 2x 4 piston caliper.

Anyway you will be wiser at the end of day :)

Falcon1651, your last sentence is why I�m building this bike:

http://i1382.photobucket.com/albums/...psmgg4fjh5.jpg

Sometimes a pain in the ass, but when it works...:yahoo:

[QUOTE=Falcon1651;213546]Hi,
Its a bit strange but in Haynes manual XTX and XTR MC are same 12,7mm.
/QUOTE]

Also strange on a jap bike is 12.7mm is 1/2"... like they
converted it to metric....

my XTR has the XTR MC & a CR250 2 piston caliper
and a 320mm disc....
works just fine....

Ernesto, it looks really cool :023:

Have you done any mods also inside the fork like change valving/springs etc?

Yes, the fork was very stiff. At first I only changed the springs,seals, sliders...When I ride fast or in a jump everything was ok, but for everyday use I feel every pothole in the road. Too harsh.

I spoke to a motocross suspension specialist and made a set up similar to a supermotard. Now is OK for me.

I�m thinking of opening a new thread for my bike, to explain what I did and to ask for advice and help because much remains to finish.

Exactly Ernesto, I think that I need to do the same - change inside settings to supermotard because the ride is really not so comfortable as it was with original forks and I expect from 300mm front fork to be comfortable :)
It would be really good to know what you did to the fork.
I will also make some build thread of my bike when I will have some free time.

I took my fork to a motocross suspension specialist that put 0.54 springs, because are the stiffer you can get to the 09 Kayaba, but due to the weight of the XT you�ll need 0.56 or 0.58, also 5W oil and SM revalving.
With the revalving and the 5W oil the harsh feel dissapeared.

I have Showa USD units in mine...
The travel has been shortened down
from 300mm to 240mm to keep the
bash plate off the ground under full
compression...
valving was changed from MX to enduro
set up..
springs are from a Kawasaki shortened
to fit...
Offroad it's great.. but still a bit soft on the road
it can wollow a bit in the corners at times..
a bit soft not qute enough damping... might
try a heavyer oil .. has motul light 15cst need
a oil with 18 or 24cst rating... motul med or heavy..
Guess yer can't have both...


pete


..

Five days ago I changed the front brake pads trying to improve the feeling and it works.

It still doesn�t have much power, but I can feel what the brake is doing and it feels more progressive than before.

Old pads were EBC HH with 35.000km, I bought the new ones in the local shop, I wanted just normal pads and the shop assistant gave me a cheap SBS pair, that ended up being HH too. I wanted no HH pads just in case the HH compound is more race oriented and the initial bite is better for normal pads, but this SBS works well for now.

Anyway this week I will try the 5/8 MC.

Ernesto, when I searched all forums about increasing power of original front brake for YZ fork I found out that the best pads you can get in YZ/WR Nissin front brake are original pads from Honda. They are the same shape/size as Yamaha since they have the same brake caliper. But I have not chance to test this by myself.

Thank you Falcon1651, but I�m using the OEM Brembo of the XT.

Well, yesterday I put de CBR master cylinder and find the real problem was the MC. When it is unmounted, I can feel the lever action is smooth, but with the OEM MC it is rough. So now problem solved. :rockwoot: