Three piston caliper revisited - Triumph Forum: Triumph Rat Motorcycle Forums
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post #1 of 277 (permalink) Old 11-08-2011, 03:50 AM Thread Starter
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Three piston caliper revisited

Well the pads are well run in and had a good ride on the weekend through some great roads north of melbourne where all the bush fires were the other year. I am totally rapped with the improvement the EBC HH pads are great as they never seem not to alter hot, cold they react the same.
The caliper allows really good feel i suppose the force at the lever is reduced due to the pressure acting over a 50% increase in area. I have wanted to improve the braking but have been loathe to spend the big bucks of some of the alternatives. The riding i do is generally fairly hard on the brakes so the two additions work well. To anyone who doesnt want to go the whole hog have a think about the EBC HH pads, sure there are plenty who have noticed the improvement.
These are the photos of the finished guard. The allen bolts are the same as the ones in the top of the guard/brace and used to fit the grab rail etc just shortened a bit. I put a black rubber washer underneath to stop the paint getting scratched.


The piece of rubber you can see attached is not a permanent fixture i just hook it on to the sump guard to stop all the gravel sparying on to the engine, i dump it in the bushes when i get to the bitumen.
I did think about painting the caliper black but was to busy fitting and trialing not much of a job to remove and paint. That means it will stay as it is!
So all that is needed is:
1/caliper (may well need a clean), i didnt replace the piston seals.
2/ Bottle of DOT 4 Fluid
3/tube to bleed.
4/set of new pads.
If you have a bonnie and want to keep your guard and want to do the method i chose:
1/drill bit the size of the original holes
2/2 allen bolts
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post #2 of 277 (permalink) Old 11-08-2011, 05:22 AM
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Very very nice.

Plasma.
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post #3 of 277 (permalink) Old 11-08-2011, 08:26 AM
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Hey Askari. Nice mod. Well done. No need to change master cylinder due to the increased surface area that the brake fluid is acting on? I would have guessed that a bigger cylinder would be required. Also, I see you still have original brake lines on. Not worth going to braided?
Cheers mate
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post #4 of 277 (permalink) Old 11-08-2011, 04:24 PM
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Quote:
Originally Posted by hurrypants View Post
Hey Askari. Nice mod. Well done. No need to change master cylinder due to the increased surface area that the brake fluid is acting on? I would have guessed that a bigger cylinder would be required. Also, I see you still have original brake lines on. Not worth going to braided?
Cheers mate
Russell
Original line is braided, I noticed when I changed mine for an aftermarket braided one.
If a larger m/cylinder is needed an early Rocket III is a straight swop. I think a Speedmaster with twin discs is also larger and a straight swop.

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post #5 of 277 (permalink) Old 11-08-2011, 06:09 PM Thread Starter
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Master cylinder

There seems no issue with the master cylinder vol wise i believe that bleeding would maybe be quicker and easier with a larger one and of course cooling, thats if you do track days maybe.
With the bleeding Ventura suggested to bleed pre bolting up, that way you can lift the caliper, twist whatever to get rid of air. I just bolted up and did insitu.
The only thing i would suggest is that you manually slide the caliper into contact after fitting. Otherwise you sart bleeding and finally get some resistance and you hear a small bang as the caliper slides over and then you are back to bleeding to find that resistance.
The cables are braided not sure if there is anything to be had in changing to an oem one other than nice colours?
Also dont be tempted to try using the original pads being in a hurry i did and they were badly worn and not worn even so they tended to bind a bit, new ones no such issue.
Pretty sure there are some on e.bay not sure which country and nothing to do with me!
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post #6 of 277 (permalink) Old 11-08-2011, 06:52 PM
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Nice job Askari!

Regarding the master cylinder, the OEM 11mm performs just fine with the 3-pot caliper.
Ive used both the stock item and also an ex Speed Triple 14mm m/c with these and the 11mm does the job perfectly.
No need at all to go bigger.

New braided lines just look a bit better than the OEM braided lines.
No need to change, other than for the 'bling' factor!

Like this maybe!!...............





V.

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post #7 of 277 (permalink) Old 11-13-2011, 09:47 PM
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Doh!

Only just got around to having a closer look at my brake lines and, bugger me, you lot are right. They are already braided. I feel like such a knob now. So my next question, at the risk of looking even sillier, is what is the caliper off? I've obviously missed something in an earlier thread.
Cheers
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post #8 of 277 (permalink) Old 11-14-2011, 02:20 AM Thread Starter
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Caliper

Hi hurrypants you wont be the last to think they are mot braided. I actually got this from europe through a friend. I believe it was from a honda, the actual model i am not sure if i remember right it was not a Aus model, however there are some Aus delivered bikes with the 3 piston caliper. Just not real sure what they were now. I did ph lots of wreckers but to no avail. Think the AUS market is a bit small. If you do a search on the site there are some models listed.
I actually PM'd you the other week as i live close, should you want to have a look/go let me know.
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post #9 of 277 (permalink) Old 11-14-2011, 05:19 AM
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Originally Posted by hurrypants View Post
No need to change master cylinder due to the increased surface area that the brake fluid is acting on? I would have guessed that a bigger cylinder would be required.
thought it worth mentioning for people experimenting with this that master cylinder size and piston diameter have a certain range of ratios that give good feel (I found this out doing research for another project I am working on).

Too big or too small cylinder to piston ratios compromise feel and performance. Get it wrong and brakes will feel either too 'squishy' or too 'wooden'.

see link here for more info on matching master cylinder to piston size (it also considers wheel size and hand lever length etc):
http://www.vintagebrake.com/mastercylinder.htm.
This site is aimed at vintage bikes but info should be of value to more modern bikes as well.

Another explanatory link is: http://www.lemickracing.com/tech-faq...verage-offsets

This may explain why Askari and Ventura found the standard master cylinder is working fine with the new calipers, sounds like the ratio is good.

Aunty Mabel
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post #10 of 277 (permalink) Old 11-14-2011, 07:23 PM Thread Starter
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Originally Posted by jonkster View Post
thought it worth mentioning for people experimenting with this that master cylinder size and piston diameter have a certain range of ratios that give good feel (I found this out doing research for another project I am working on).


This may explain why Askari and Ventura found the standard master cylinder is working fine with the new calipers, sounds like the ratio is good.
Interesting info jonkster. The only thing that i would add and that is the pads themselves make a lot of difference as well. I havent tried all the permutations but from others experience there seems to be a great effect. I found the standard pads on the 2 piston calipers didnt give much feel and were a bit wooden, this became markedly so after fitting the hh pads and 3 piston caliper.
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