Would these fit my stock '87 and be an improvement ???

[ribbert]

It appears I don't know as much about brakes as I thought I did.
Could someone tell ME then, without anecdotes, why blue dots are better.

Noel

[Pat Conlon]

I think Fred brings up a good point, about the necessity of the 14mm m/c in the mix.

On my '84, when I did the late model fork lowers, FZR rim, R-1 blue spots and Spiegler lines, yet I was still using the FJ oem 5/8" m/c, I remember thinking, yea, these brakes are better....but still not that great.

It was only after I added the FZ1 14mm m/c did I really notice the improvement in being able to better modulate the front brakes. 2 finger braking at its best.
I've concluded that the front brake system is just that...a system. The synergy of parts working together.
Leave out one part, and your results will be less than optimal.

That said, I've always wondered if a modern radial m/c would improve things even better...? Comments?
I just can not get my head around at looking at a urine cup on my handle bars

[Pat Conlon]

It appears I don't know as much about brakes as I thought I did.
Could someone tell ME then, without anecdotes, why blue dots are better.

Noel

Here's my take:
The 1 piece body is stiffer, stronger than a bolt together 2 piece caliper, and given the same amount of pressure from the m/c, thus able to transmit more hydraulic force to the pistons, thus the pads, thus the rotor.

[simi_ed]

Leon, I was thinking of our emails back & forth about updating to blue dots.  You were a hard sell!!!  Like me, you didn't want to drink the Kool-aid, yet you too are a convert to the Church of the Blue-Dot.  Hallelujah    

Noel, I think that Frank's (Flynt) explanation of the reduce piston area with more linear area, more braking potential due to the use the outer rotor surfaces and my description of the visible flexing of the late model 4 piston calipers sum up what's happening and the improvements.  If you don't believe, that's OK, you're entitled to your opinion.
Maybe refresh your memory of the "sales pitch" we had to do on Leon http://www.fjowners.com/index.php?topic=2057.0 to finally convince him to upgrade.  I don't think he's going back to OEM calipers; in fact I've NEVER heard of anyone that has done the upgrade and them gone back to OEM.

[ribbert]

Ed, you've combined the two things being discussed into the one post. Single vs multi piston and blue dot vs standard (late model) calipers.

The explanation about maximum effect being at the outer part of the disc and this being the sole reason for multi piston calipers and hence rectangular pads was mine not Franks.
A point that seems to have been widely missed is this is not my opinion, it is a fact.

 ........If you don't believe, that's OK, you're entitled to your opinion..........
.........Maybe refresh your memory..........

FFS, words fail me!



This discussion is futile, forget I spoke, we are obviously on a different page here.

Noel

[ribbert]

I just can not get my head around at looking at a urine cup on my handle bars

Pat, these black anodised covers tend to "disappear" into all the other handlebar hardware.  I have seen them in the flesh, not too bad if you're stuck with a urine cup. Way smarter looking than socks.



Noel

[CatTomb]

Pat, Leon, Fred, Ed and Noel - Thank you!  

After reading replies and rereading past posts, I'm thinking I should replace the brake fluid and, as Pat has been suggesting since I first considered the bike, SS lines. (insert brick-thick skull cartoon here)

I can't play the banjo, would this package work? I found the link in a previous post (thanks to Fred)

http://www.ebay.com/itm/86-87-YAMAHA-FJ-1200-Non-ABS-Front-Brake-Line-Kit-Braided-S-S-Brake-Lines-/400378230354?pt=Motorcycles_Parts_Accessories&hash=item5d3866f652&vxp=mtr

I searched without success for a post of brake bleeding tips ... any FJ specific tips would be greatly appreciated.

[simi_ed]

Never Mind

Leon, I was thinking of our emails back & forth about updating to blue dots.  You were a hard sell!!!  Like me, you didn't want to drink the Kool-aid, yet you too are a convert to the Church of the Blue-Dot.  Hallelujah   

Noel, I think that Frank's (Flynt) explanation of the reduce piston area with more linear area, more braking potential due to the use the outer rotor surfaces and my description of the visible flexing of the late model 4 piston calipers sum up what's happening and the improvements.  If you don't believe, that's OK, you're entitled to your opinion.
Maybe refresh your memory of the "sales pitch" we had to do on Leon http://www.fjowners.com/index.php?topic=2057.0 to finally convince him to upgrade.  I don't think he's going back to OEM calipers; in fact I've NEVER heard of anyone that has done the upgrade and them gone back to OEM.

[Flynt]

I've always wondered if a modern radial m/c would improve things even better...? Comments?

I have the one that was on Klavdy's bike...  replaced it when I did the big overhaul on Wiz.  IMHO that m/c felt like squeezing a 2X4 (no feel whatsoever) and the FZ1 MC is a 1 finger operation (with the 320 Brembo rotors and EBC HH in front).  Night and day difference.

If you want to try a radial m/c, I'm happy to set you up.

Frank

[RD56]

Just because they have more pistons doesn't necessarily make them better.  Buy some good brake pads for your stock calipers and you'll improve your brake performance.

Here's a test; which would provide more braking force, a caliper with 2 60mm diameter pistons or a caliper with a single 90mm diameter piston?

A great mechanic friend of mine gave me some basic info about brakes that I've never forgotten. Brakes convert kinetic energy into heat. "Piston AREA not diameter affects the force." Quotes because they're not my words.

Rick

[RD56]

I think I also read somewhere in this thread that adjustable levers made a big difference in (his/her) braking. Again, I will quote, "for brakes to convert kinetic energy into heat they must be applied with great force...The primary mechanical principle used to increase the application force in every brake system is leverage." So kudos to that person who suggested adjustable levers to increase leverage. AMEN.

[The General]

I think I also read somewhere in this thread that adjustable levers made a big difference in (his/her) braking. Again, I will quote, "for brakes to convert kinetic energy into heat they must be applied with great force...The primary mechanical principle used to increase the application force in every brake system is leverage." So kudos to that person who suggested adjustable levers to increase leverage. AMEN.

I don`t usually comment on things mechanical `cause I didn't want to remove all doubt on my expertise, but I can tell ya I first learned about leverage on my school push bike.

When ya turned tha thing upside down and spun a wheel it was far easier ta slow it down by placing the fingers against the spokes further out from the axle compared ta closer to the axle (which did make my fingers hotter!). I eventually developed this new found knowledge further into my combat strategy.

One particular bully use ta ride pass me real close from behind, whenever he had the opportunity on the way home from school. I practised it a bit before I got it right, but if you grabbed his rear tyre with confidence (The most outer distance from tha axle) with my strongest hand (Never did develop the grab inta two hands which woulda been better if he was going real fast!) followed by immediately  lifting up (opposite ta Gravity) while swinging my mass directly behind his direction of force, I could easily stop dead the mass of said pushbike.
However my leverage was not enough to have the same affect on the riders body mass.....which continued forward.....this of course left me at a considerable advantage for the following heat!

True story, but Yeah I`m bored cause I got given a brand new 4 wheel drive at work yesterday (with two diff locks and massive tyres!)...and I`m not allowed ta play with it till 8.30am. Can`t wait ta take some pics too! 

[RD56]

+1 for diff locks!!

[FJ_Hooligan]

Just because they have more pistons doesn't necessarily make them better.  Buy some good brake pads for your stock calipers and you'll improve your brake performance.

Here's a test; which would provide more braking force, a caliper with 2 60mm diameter pistons or a caliper with a single 90mm diameter piston?

A great mechanic friend of mine gave me some basic info about brakes that I've never forgotten. Brakes convert kinetic energy into heat. "Piston AREA not diameter affects the force." Quotes because they're not my words
Rick

So what's (PI/4)*Diameter^2?

I think I also read somewhere in this thread that adjustable levers made a big difference in (his/her) braking. Again, I will quote, "for brakes to convert kinetic energy into heat they must be applied with great force...The primary mechanical principle used to increase the application force in every brake system is leverage." So kudos to that person who suggested adjustable levers to increase leverage. AMEN.

Adjustable levers don't change anything except the distance they are from the bar.  Unless they are longer, the leverage is the same since the pivot point of the lever is fixed.  The primary force multiplication in a braking system is hydraulic multiplication.  You get that by applying force on a small diameter/area piston which creates a pressure in the fluid (psi).  In the caliper, that pressure is applied to the larger area of the pad piston thus creating a force that presses the brake pad against the rotor. 

Simple math. On the master cylinder side: Force/area = pressure.  Higher force or smaller piston area increases pressure
In the caliper: Pressure * area = force.  For a given amount of pressure, a larger piston generates more force.

You want the "great force" to be generated in the caliper, not with lever pull. 

[movenon]

FJ piston diameter 5/8" (about 15.8 mm).  I think the R1's / R6 etc. are 14mm diameter?  When I get to that point I will go with a 14mm piston.  
And stay with DOT 4   .
George