| Author | Message | ||
     Henrik |
Lornce; my physics and fluid dynamics are quite rusty  , but ... Isn't it true, that no matter the area of the brake internals, the pressure is the same per sq. inch? If so, how would larger brake pistons make a difference? Henrik (I really don't know - just trying to learn) | ||
| Lornce |
"Isn't it true, that no matter the area of the brake internals, the pressure is the same per sq. inch? If so, how would larger brake pistons make a difference?" Henrik, Yes, pressure is equal throughout an hydraulic system regardless of dimension (if we consider this simply without factoring subtle variables of hydrodynamic flow etc.).... but.... the *applied force* at the caliper is a direct result of the ratio of the areas of the master and slave cylinders (calipers). Resultant force is what we're concerned with here as that's what pushes pads against rotors. Here's an example using round numbers for simplicity's sake: Suppose our system uses a master cylinder piston with an area of 1 sq.inch. Suppose this same system uses a caliper whose six pistons have a combined effective area of 10 sq.inches. Now let's apply enough force to the brake lever to produce 20psi of hydraulic pressure at the face of the master cylinder. As you stated, that same 20psi of pressure will be present throughout the hydraulic system including it's acting upon the 10 sq.inches of combined caliper piston area. The ratio of the areas of the caliper cylinders to the master cylinder is 10/1. Therefore, 20psi multiplied over the 10 sq.inches of effective caliper piston area would result in 200 lbs of force being exerted upon the brake pads. ie: 20lbs exerted at the m/c results in 200lbs of force at the caliper because of their 10/1 ratio of comparative areas. So do you now see how the 1/2" master cylinder will create more resultant braking force than the 5/8" master cylinder? Assuming both caliper's share identical effective piston areas, the caliper being driven by the 1/2" master cylinder will create a greater "hydraulic advantage" due to a higher piston area ratio than will the 5/8" m/c acting upon the same caliper. Think of the piston ratios in the same way you'd consider fulcrum points and moment arm lever length ratios to calculate mechanical advantage. It's the same sort of thing: it's just liquid leverage. Hope I've been able to explain this in an understandable manner. Sorry if it's sketchy, but I'm told I'm a "visual thinker" and understood these principles visually long before I ever considered them in mathematical terms. best, Lornce | ||
| Henrik |
Thanks Lornce - I get it. The key point is that I didn't take into account that pressure is measured in mass/area ... lbs/sq. inch. From vague memory, I think the PM may have larger pistons than the Nissin?? Anyone know for sure? Thanks Henrik | ||
| Blake |
pressure=force/area There will be a quiz later. Lornce, Just one clarification to your excellent treatise on hydraulic multiplication of force... If half of the calliper's pistons are directly opposing the others, the total clamping force would be half what you calculate in your example. In other words, you could replace the opposing pistons with a solid unactuated surface like the rear brake does and still achieve the same brake clamping force. | ||
| Lornce |
Or force=pressure x area "Lornce, Just one clarification to your excellent treatise on hydraulic multiplication of force... If half of the calliper's pistons are directly opposing the others, the total clamping force would be half what you calculate in your example. In other words, you could replace the opposing pistons with a solid unactuated surface like the rear brake does and still achieve the same brake clamping force." Blake, Perhaps we're stumbling over semantics, but half the caliper's pistons do oppose each other. The total applied force remains the same. How could it not? In the case of a floating single piston caliper (like the rear) the resultant braking force is still a function of master/slave piston ratios. ie: if two calipers, one single piston floating and one twin piston opposed, had the SAME combined effective piston area and were driven by an identical master cylinder.... They'd create an equal amount of resultant braking force. Albeit, one in a much more cost effective manner.... Capische? | ||
| Lornce |
Henrik (or anyone else who knows about this stuff), Will S3T bags fit S2T bag mounts? Also, does anyone know a slick way to make an S2's drooping mirror stand to attention? | ||
| Dave |
S2 mirrors-a drop or two of Lock Tight in that ball joint DAve | ||
| Henrik |
Lornce; no they will not. You can buy a bracket/kit from the factory, that will allow you to mount S3 bags on an S2. Keep in mind though, if you do that, that you'll save about $60 by getting some of the listed parts from other sources. Also make sure you reinforce the mounting area for the turn signals, otherwise they may tear out a chunk of the splash guard. Mirrors have been discussed before. Todd uses red loctite. FMJ has "peened" the mating surfaces with fine punch for extra friction. Both supposedly works. Henrik | ||
| Lornce |
Oh poop. Was hoping I'd overlooked some sanitary esoteric trick to open the mirror and pre-load the ball socket. Peening it shall be then.... As re. the bags, (sorry to belabour the point) but will S3 bag lids fit S2 bag bases? I've never actually seen an S2 bag in "real life". FMJ: are your S2 bag bases salvageable? tia, Lornce | ||
| Lornce |
Dave, Thanks for the loctite tip. Love your profile pic. Is that the Angeles Crest? best, Lornce | ||
| Henrik |
S3 bag lids fit S2 bag bases I seriously doubt it, but will check. Henrik | ||
| Blake |
Lornce, Your calculation using a total caliper piston area of 10 sq in would yield double the actual applied braking/clamping force for an opposing caliper system like on the front of virtually all sport bikes. That is to say, with equal piston areas, an opposed piston caliper brake system will develop half the braking force as a non-opposed system with all else being equal. Your original calculation would be correct for a caliper with no opposing pistons, like that of the rear brake on our Buells. It would yield half the braking/clamping force for an opposed piston caliper. Think of it like holding a spring between your opposing hands and compressing it as hard as you can, applying 100 LBs force through each arm. The spring sees how much load? Now set the spring on the floor and push on just one side with one arm and compress it applying 100 LBs. The spring sees how much load? The opposing pistons in brake caliper do not increase braking force, they serve to maintain optimum alignment between rotor and caliper. | ||
| Lornce |
Blake, I was aware of the obvious alignment advantage of opposed piston calipers but wasn't aware of the effects on resultant force. The spring's a useful analogy. Guess all yer spendy schooling wasn't for nought.... edited by lornce on June 09, 2004 | ||
| Blake |
Thank the lord for that, cause it darn sure was "spendy." | ||
| Henrik |
Thanks for the lecture guys. It's good to learn  Henrik | ||
| Mikej |
S2 fairing mount bracket: Has there been any issues with the fairing mount bracket breaking on the S2's? I either have paint cracking/chipping on the lower forward protruding horizontal rods near the welds, or have cracks forming. I've also got an Italian track bicycle with hard paint that has formed cracks in the paint so I'm thinking/hoping that the Buell is just cracking paint like the bicycle. In the mean time I may be looking for a spare S2 fairing bracket mounting assembly if anyone has a spare one hanging around. I'd like to have one to use while I work on the current one, otherwise I'll just have to run it naked while the fairing is off and the bracket is removed for paint removal and crack checking. Thanks. Mike. | ||
| Bomber |
mike -- just got a tire at Uke's (destroyed the 205 on the MaDeuece Saturday night with a chuck of scrap metal) . . . . 20% just a data point! | ||
| Mikej |
 I priced a tire when I was down there, the 20% you're talking of must be either a card carrying membership deal or the percentage of tread you had left on the old tire? | ||
| Bomber |
nope, special deal going on now . . . . give em a shout | ||
| S2pengy |
MikeJ Hell yes that was the first recall and is why they added the mounting point on the frame neck.... Happened to me in Daytona in March of 96 on my 95 S2. Broke just forward of the lower end of the tank cover on both sides, forward of where the fairing slides into the frame .... The whole fairing came off and was bouncing on the front fender by the wiring.... | ||
| Court |
>>>Hell yes that was the first recall and is why they added the mounting point on the frame neck.... That is accurate. Check to make certain you have the brace. If not, it can easily be retrofitted as mine was. Cracks in the paint, where the bracket enters the frame at the horizontal tube, are not unusual. I don't worry, just keep an eye on it. | ||
| Mikej |
S2, that sounds like it would be strangly scarey. My bike has the brace, or at least a brace of some sort going from someplace under the upper tripletree and heading down to the front of the fairing someplace. I was looking at it on the way home last night, but figured I should probably pay attention to the road ahead instead. Forgot to look closer when I got home as to how it's mounted. I'll just keep an eye on it, and give it the occasional upward tug once in awhile. Got a second fairing I plan to do some mods to, when that gets done I'll probably do some selective paint stripping on the bracketry. Thanks for the replies. | ||
| Rex |
I guess I need to go out and look at mine...a brace from under the triple trees, huh? rex photo? | ||
| Lornce |
Anyone ever use Cometic three piece head gaskets? Local H-D/Buell performance guru recommended them so they were included in my recent S2 T-Storm transplant. Note: they have a different torque value than stock gaskets. Stock spec is incremental increases from 9ft/lbs to 14ft/lbs then a 1/4 turn. That's what I did and when I fired it up had badly leaking heads. A quick call to Cometic and the tech rep.... called ME back... in Canada! Wow, great product support. Anyhow, the routine for the Cometic three piece perf gaskets is 9ft/lbs 14ft/lbs 22ft/lbs 35ft/lbs and finally 42ft/lbs. Once that was done, no problemo. best, Lornce | ||
| Bluzm2 |
Just so the poor folks that don't have one of these fine beasts know what we are talking about, here's a picture of the bracket. At least I think this is what Court is referring...  | ||
| Firemanjim |
That's the one,unless you have the early S-2 and then you get this engineering marvel.  | ||
| Boat |
Does anyone have any advice for the upgrade from the '99 Showa to the K1400 rear shock. I have spoken to the HD/Buell dealer and they don't seem to know to much about it. They did find the service bulletin dated Nov-20-2000. They asked me to bring my bike by so they could see it. What if any charges could I expect to pay. Oh yea its for a '95 S2. I have posted this in a different area, I think this is the best place huh. Thanks, Randy | ||
| Rex |
Pictures sure work..the top photo bracket is what I have on my bike...thanks, REX | ||
| Doughnut |
I don't think I have either of those braces on my fairing. Where do I go to get one? | ||
| Firemanjim |
Your S-2 is a 1996,right.Should have the bracket shown in the first pic,if not someone removed it and you need to find another.I don't think I have one,but will look.You should have a welded tab on front of steering neck for bracket to attach to . | ||
| Tbolt834 |
You guys are great!! My S2 is an early '95 (March if I remember correctly) and I'm going to check it tonight. Thanks Dave | ||
| Mikej |
Doughnut, Go to Hal's and have them check it for you. You should be able to see the bracket when you are seated on the bike and looking down at the fairing. Easy to not notice it until you start to look at it. It's probably there, but worth checking/verifying. Mine's a fairly early one, but with the upper bracket. I wouldn't mind finding one of the older brackets with the paperwork if someone had one they wanted to unload. $20 to the Cancer Fund Raiser if they do. | ||
| Doughnut |
Checked my S2, I've got a brace. Thanks all. Take care, be safe. | ||
| Doughnut |
My rear left turn sig. broke off taking some of the fiber glass with it. I have a fiberglass "doughnut" chip now. What is the best adhesive to use to reattach this small piece? I thought about using a fiberglass repair kit, but the piece is so small and fits back in place so well that I thought it would make more sense just to glue it back in some how. | ||
| Henrik |
Doughnut; been there, done that. On it's own, I don't think an adhesive will work. I cut a strip of thin stainless to fit inside the tail, where the turn signals bolt on. Drilled hole(s) to fit the tail light threaded stud, and glued the SS piece in place inside the tail - I think I used Goop. Then sprayed it with flat black paint. I then glued the fiberglass chip back in place, and bolted the taillight back on. I did the other, non-broken, side as well, just as a precaution. It's held up for some 5000 miles so far. Henrik | ||
| Doughnut |
Just making small talk. What it the 0-60 and top speed of the S2, stock? | ||
| Court |
>>>>What it the 0-60 and top speed of the S2, stock? Frankly, they are not impressive nor important numbers on the S-2. The 0-60 I am not certain of. The top speed is in the 120 MPH area. It will do a bit more, but not easily. On the other hand, the S-2 "really likes" 115MPH, I've had one there for 60 uninterrupted minutes. The S-2 is NOT a high speed (ala ST100) tourer. It is most happy at 80MPH. But....... The S2 is without peer in the satisfaction is provides. Put one of these bikes into a section of twisty road for FUN and there IS NOTHING BETTER IN THE WORLD. I've spent 31 consecutive days, many of them riding 18 hours a day, and I always hate to get off the bike. Not sure I can explain WHY the S2 does this, but I am certain it does. Note that nearly all the multiple bikes owners eventually end up with an S2 as THE bike they won't part with. Aaron, Henrik, FMJH, etc. I keep one under a blanket in the basement for times when I need to be reminded of how much fun motorcycling can be. That help ? Court | ||
| S2pengy |
My 96 was clock at 129 by radar on a race track... | ||
| Mikej |
0-60 times? Sufficient. Top speed? More than sufficient. Don't worry about it, Just ride. Plenty quick enough for freeway onramps with short tight cloverleaf approaches and narrow traffic gaps to knit into as I proved Tuesday. | ||
| Bluzm2 |
Yeah! What Mikey said! |
