Brembo Master cylinder

[diesel pig]

I thought I would ask on here as well as trying to figure it out myself. I have a pair of Brembo 05's for a Post classic race bike. I got them to replace a pair of sliding pin caliper's on it originally and just used the Master cylinder that was all ready on it, it was a bit wooden but OK. But for the life of me I cannot find it now. So what Bore size Master cylinder suits Brembo 05's for racing? If I am lucky, I will have that size in the shed or at least know what size to buy. Cheers

[diesel pig]

Typically, I went to myself " i didn't look in that box" and you already know what was in the bottom that box. It turns all it is a 19mm bore size which going by the chart I have looked at point to the brembo 05's feeling a bit soft and 17mm would be a bit quicker acting and harder feeling. I would welcome any thoughts on the matter. I would of thought the 17 would be softer and the 19mm harder.

[jato]

you are right - the smaller master cylinder gives more pressure for more travel

[neels]

Typically, I went to myself " i didn't look in that box" and you already know what was in the bottom that box. It turns all it is a 19mm bore size which going by the chart I have looked at point to the brembo 05's feeling a bit soft and 17mm would be a bit quicker acting and harder feeling. I would welcome any thoughts on the matter. I would of thought the 17 would be softer and the 19mm harder.
Force x surface area, so the larger bore will feel softer for the same force being applied at the caliper, the smaller bore harder and more travel to move the volume of fluid. I think.

[F5 Dave]

No. Jimi is right and you are wrong sorry.

Think of it as leverage.

Take things to extreme to illustrate your point.

A 1mm bore would displace hardly any fluid and would go to the bar easy. But it would have incredible advantage.

A 60mm piston would be like wood and not move. You'd be better putting you feet on the ground gor the effect it would have.

[F5 Dave]

Old yamahas had such flexible deteriorating rubber lines that once you replaced them with braided they had little movement or 'feel'. They actually needed smaller cylinders to get them back into the sweet spot of travel that riders like.

That would also create more leverage. More power applied to the disc.

I like to go low on size and see if you can bleed it to get it firm enough. If there is too much travel it is not safe to use. Go up a size.

[F5 Dave]

You can also do this with mechanical leverage.

Make your brake lever 500mm long but bend it so your fingers can reach. Damn it's super powerful at first. But your run out of travel before the piston can really get some stroke.

Next buy some fancy Shorty levers from Aliexpress. . Hmm. Less leverage.
(I don't care if you think you only use 2 fingers. Look how the slide to the end on a longer lever. Dirtbikes ride on slippery surfaces).

This works well on heavy clutches. Extend the engine lever to make it lighter.

But the limit is -the better leverage means less travel. Ok up until it still drags fully in.

[neels]

Yeah, that stuff kind of bamboozles my brain, as it's application of force and also displacement of fluid.

That tracks once I actually think about it though, larger clutch slave on the ducati makes the lever lighter, but longer travel. So presumably the reverse, smaller master, would have the same effect.

[Kickaha]

The 05 is the smaller caliper fitted to the Pantah , I doubt it'd be much bigger than a 13mm master cylinder, I had a 14mm m/c on the MHR I had with the 08 calipers which gave good feel, my Darmah with the 08 calipers had a 15mm m/c which always felt a bit on the hard side, the 05 should be a 32mm caliper piston compared to the 08 at 38mm

[diesel pig]

The 05 is the smaller caliper fitted to the Pantah , I doubt it'd be much bigger than a 13mm master cylinder, I had a 14mm m/c on the MHR I had with the 08 calipers which gave good feel, my Darmah with the 08 calipers had a 15mm m/c which always felt a bit on the hard side, the 05 should be a 32mm caliper piston compared to the 08 at 38mm

How Annoying! I just checked the calipers with verniers and they are 08's I mucked up and thought brembo's did smaller numbers bigger brakes but it is larger numbers bigger brakes (those bloody Italians being logical for once!) I will have to do the numbers again.

[diesel pig]

I must of done my home work the first time as the chart says 19mm would work well for 08's for racing. And it was for the reasons F5 pointed out.

[Kickaha]

I must of done my home work the first time as the chart says 19mm would work well for 08's for racing. And it was for the reasons F5 pointed out.

I'd be surprised if it does, the 15mm with twin 08 had a hard lever feel and 19 is a big step from that

[diesel pig]

Well, I will mount it up and bleed it and see what it's like.

[F5 Dave]

Most twin setups, well Japanese callipers, use 5/8 which is 15 and a bit. Newer setups use 14mm.
19? Radials are often 19 but they use different leverage due to positioning. Won't be legal for classic.
I suspect you are not reading the correct bore size. Usually underneath near banjo threads.

[diesel pig]

Thinking about this at the gym this morning. Going with Big bore M/C with a pair of 08's meaning fast acting and short lever travel would suit my mutant dimensions of small hands and short fingers. Since I am building this race bike for my cousin who is a lot taller than me so might have bigger hands than me as well. A smaller Bore M/C with more travel may suit him better. I should see him at the end of the month and check it out then.

[diesel pig]

Most twin setups, well Japanese callipers, use 5/8 which is 15 and a bit. Newer setups use 14mm.
19? Radials are often 19 but they use different leverage due to positioning. Won't be legal for classic.
I suspect you are not reading the correct bore size. Usually underneath near banjo threads.

For F--K Sake, Do you ever not have something good to share. When I was looking at the M/C last night with a torch. I could not make out if it said 5/8 or 6/8. So I went with the bigger number to be safe. I will have to have another look.
The M/C is Not a Radial one. I suspect you may be right about the size. Damn it!

[jellywrestler]

For F--K Sake, Do you ever not have something good to share. When I was looking at the M/C last night with a torch. I could not make out if it said 5/8 or 6/8. So I went with the bigger number to be safe. I will have to have another look.
The M/C is Not a Radial one. I suspect you may be right about the size. Damn it!

6/8 would be noted as 3/4 so it's 5/8th

[diesel pig]

6/8 would be noted as 3/4 so it's 5/8th

F--k it! That is what my digital verniers keep telling me when I tried to used them to tell me what 6/8 was and it keep showing 3/4. So I google it. I hate Factions of inches. Metric system the only good thing to come out of France.

[F5 Dave]

That's a goddam lie.
There's also Michelin tyres.

Some people like the wine, but I'll pass on red mostly.

[F5 Dave]

Thinking about this at the gym this morning. Going with Big bore M/C with a pair of 08's meaning fast acting and short lever travel would suit my mutant dimensions of small hands and short fingers. Since I am building this race bike for my cousin who is a lot taller than me so might have bigger hands than me as well. A smaller Bore M/C with more travel may suit him better. I should see him at the end of the month and check it out then.

Small hands would need to be strong fingers. Go for smallest master for most power. Classic brakes are never much to write home about but tyres have got better.

[diesel pig]

That's a goddam lie.
There's also Michelin tyres.

I stand by what I said. I am a Dunlop man, Bridgestone if I cannot get them. But Michelin? I tried them once but ever again. Did not like how they worked on the edge of grip.

[Kickaha]

Pretty sure Black Betty used a 15mm

[F5 Dave]

I stand by what I said. I am a Dunlop man, Bridgestone if I cannot get them. But Michelin? I tried them once but ever again. Did not like how they worked on the edge of grip.

I'm out of date. Butt fuck. Dunlop slicks were like a super power. On kart tracks you could take such liberties that a 50 could pass 150s in corners and if you got ahead of them you'd be OK.

But Michelin road tyres are generally pretty good.

I've gone off Dunlop road tyres.
Except Trailmax Raids that are on my Adventure bike.

[F5 Dave]

I'm enjoying this thread. I'd like to come down that way sometime. Maybe for dirtbike ride ot a Syd ride if they still do them. Read about it while lying in hospital not knowing what the future held. Must get the T125 going.

[diesel pig]

Once I start working again* I should be able to afford to start working on my T350. (just so no one freaks out. I won't made it faster just nicer to ride especially around corners. I think the Yanks call it rest-o-mod-ing basically think of a T350 from the early 70's but owned by a enthusiast.) a ride with fellow nutter would be cool.

* Yeah it's been a Long Long haul.

[diesel pig]

Pretty sure Black Betty used a 15mm

Bloody Hell, I should just consult you in the future on Betty you memory is better than mine.

[diesel pig]

I must admit I was really talking about my experience on slicks but I base my road tyre choice on what tyre brands were like in races.

I will do the 5/8" M/C on the pair of Brembo 08's this Saturday and see what they feel like. I now realise my ignorance of betty's brake set up was total.

[F5 Dave]

thusiast.) a ride with fellow nutter would be cool.

* Yeah it's been a Long Long haul.
You're not kidding. . Years not so far back for me.n

[diesel pig]

So I checked the M/C again and it is 5/8" so just over a 15mm bore. Why a Japanese M/C is in factions of inch is beyond me. It has better feel than I remember. I wonder if I did changed the M/C at some point because I do remember the front brakes feeling very wooden at one point.

[F5 Dave]

Assume you have braided lines. Try a 14 and that will give more power.

Saturday night. Couple of beers and a wine or two.

Right. Let's get onto pressing matters.

So are Lockheed calipers available?
How about getting HRC to build us all 2 strokes while pissing on Sirochios grave?.

[F5 Dave]

Just sayin ;)

[diesel pig]

[QUOTE=F5 Dave;1131239356So are Lockheed calipers available?
How about getting HRC to build us all 2 strokes while pissing on Sirochios grave?.[/QUOTE]

The last time I checked they were but were priced to make the brembo's very cheap by the by.
Forget about Honda's, The way the Euro 300 enduro's are going Yamaha need to pull a finger out and do a case reed balance shaft electric start maybe DFI YZ300X.

[Kickaha]

So are Lockheed calipers available?


I have a couple in stock

356537

[Kickaha]

The way the Euro 300 enduro's are going Yamaha need to pull a finger out and do a case reed balance shaft electric start maybe DFI YZ300X.

It's already out there in the form of the Fantic 300

[diesel pig]

It's already out there in the form of the Fantic 300

Yeah But it's not case reed or balance shafted. Once you have a go of a balance shafted T2 your opinion of non-balance shafted T2 go's down.

[F5 Dave]

The Betas have a balance shift.

That said my GG 07 didn't but it was still great.

[diesel pig]

T2? What the hell was I on about! I meant Two Stroke of course. My cousin was over this weekend pass to race his KTM390 at Ruapuna, So I got him around to my place to sit on Betty to get the pegs and bars in the right places and he was happy with the feel of the 5/8" M/C on the pair of 08's as well. So after much worrying it turn out OK. Thanks for all the help.