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Discussion Starter #1
I just installed a 250 Ninja master cylinder off Ebay to test the effect on front braking. http://www.ebay.com/itm/370886528553?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Yep, $25.00 delivered..... It includes reservoir, banjo bolt & washers, brake light switch. It took about 15 minutes to remove the stock master, install this one & bleed. I will pump it up and bungee the brake lever over night to see if there's any more tiny air.

The lever is longer, has stroke adjustment and just fits with my bark busters. After lubing the pivot points, the braking effort is very significantly reduced. The front brake is improved as indicated by shorter stopping distance and increased front end dive being apparent. I think I'll keep it on the bike.

This master has a 10 mm bore as opposed to the stock 12 mm which about 50% increase in application pressure, all things being equal. There seems also to be a bit of application slack (clearance) like with the original KLR master so will play with inserting some shim stock while checking to make certain that the compensating port remains clear.

One caution is that I don't think that this will work with the stock front hose because the expansion of the hose under pressure is estimated to reduce application volume too much for the smaller master cylinder delivered volume.

I still plan to do the dual piston caliper upgrade at some point and then assume that this master will not produce enough volume. It will be interesting to see the effects. For $25.00 which I can recoop when someone needs a master on a smaller bike...way-the-hay?
 

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Wow chrome. Bling on a KLR.

Thanks for experimenting with this. I've seen some of that stuff on eBay and wondered if it would work. Looking forward to your experience with the dual caliper upgrade.
 

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Discussion Starter #4
Just returned from 50 miles of mixed freeway, country and city riding. I bungee corded the brake lever over night which seems to have dissolved some trapped air and improved the brake residual travel even more. I'm very pleased. It remains to have others compare with their bikes but it's staying on mine for the time being.

I'm looking for a stock Gen2 front rotor as it looks like I can make an adapter plate to mount the two piston caliper I have to use with the larger Gen2 rotor. Interesting to play with these things.

I was able to pull the stock lever to the grip but this one has a longer lever, apparently some compounding and smaller bore so the increase in braking is noticeable. The front tire chirps on harder pulls. I don't know what pads are on this bike as haven't paid attention when they were off. It might be that there is some opportunity there also...
 

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Discussion Starter #6
A quick guesstimate shows that the pad area of the SV650 caliper is about 150% of the Gen1 KLR. The swept area of the 280 mm rotor is 110% per revolution, of the 260. Ninja 10 mm master versus stock KLR 12 mm. SV650 piston area is 125% of KLR piston area.

So what is possible from a master cylinder which applies 150% of the pressure + 150% pad area + 125% piston area + 110% swept area per revolution?
 

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The master cylinder piston area is proportional to the square of the diameter, thus the ratio looks like 144/100, or 1.44 increase, comparing the application pressures to me.

The pad area does not figure in the static friction equation; the force of friction is equal to the coefficient of friction times the force pressing the surfaces together only; similarly, the "swept area" isn't involved in static friction consideration.

[Caliper] piston area? With 125 % piston area, under the same pressure, I'd expect 125 % of the force pressing the surfaces together, given the same hydraulic pressure.

Braking effect? Should increase linearly with the increase in rotor diameter.

Clearly, you'll obtain greater braking effect the way you're going; modulation and control may become critical factors.
 

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Discussion Starter #8 (Edited)
A test ride showed that the pads which came with the caliper needed some attention. The braking was very poor initially but heated them up and they seem quite good for now. I don't know that they are as have been focused on the fitting. The Ninja master cylinder's stroke is on the edge with this caliper volume. I will surface the pads when I remove the caliper to paint and detail the fitting.

The pad make & model was part of my problem in considering friction as no way to determine even the base line. I could only agree when reading Damocles' points as cannot tie it together as yet...maybe ever? ;-)

Anyone know of a pad clamping pressure to friction chart for any bike disk pads? I'm interested as to how the "curve" trends.

OK, the impressions:

Next to new (couple of hundred miles?) Shinko Trail Master 3.00 x 21 with Tubliss on front, FWIW.

Wet road/damp road pulling the lever nearly to the grip locks the front tire and deflects the forks such that had one near miss from dumping the bike. OK, not bad!

Dry road (about 14- 15 C or 60 F) the tire cries and slides intermittently. I could manage to lock it up with a very quick and hard application. If had a tiny bit more stroke, it would lock completely. I might stick another dime to the master piston.

I think that I'm at the point where don't need any more braking effect unless ABS were available.

The set up is: 250 Ninja master cylinder with slack shimmed, braided brake hoses, Gen2 front rotor with bolt holes counter bored by 0.035", Suzuki SV650 master cylinder with unknown pads, Deville adapter plate to mount caliper to fork leg.

Cost was very low for the set-up, excepting for the unknown of the adapter plate. If there is interest, I will consult Terry to obtain a quote for a batch.
 

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Discussion Starter #9
Some follow up on the front brake modification in the form of hypothesis:

The master cylinder used on Gen1 & Gen2 are the same therefore the lever effort to pressure is the same.

The caliper piston area is virtually identical between Gen1 & Gen2 front calipers, therefore the clamping effort is the same for both calipers.

The rotor diameter is 260 mm versus 280 mm which means the average swept distance per revolution of Gen2 is 110% of Gen1.

The pad area for Gen2 is 120% of Gen1 pad area.

Gen2 braking is better than 110% of Gen1 so the improvement (given the same pads EBC HH) therefore some other effect must be providing the extra braking.

A frequent claim is made that brake pad area/size has no effect on brake friction but this is clearly not correct. Another factor is that braking effect/friction is not linear with apply pressure/clamping force. One can recognize this by simply experiencing the braking effect of any vehicle under increasing lever or pedal effort.Applying a given pressure to the pedal or lever provides a degree of braking. Doubling the application effort may double the braking or result in greater or lesser braking which shows that the relationship is not linear.

When one reaches a certain degree of braking, applying additional effort to the lever or pedal results in very little braking increase because the pad to rotor friction has reached maximum. At this point, adding increased pad area to the same caliper will result in increased braking.
 

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Discussion Starter #10
We did another SV650 caliper & Gen2 front rotor modification to a Gen1. The 250 Ninja master cylinder was broken so we used the stock KLR master for the time being.

Mike found braking to be much improved over stock. He could not duplicate my (with the 250 Ninja master) howling front tire and rear off the pavement but that will come when the master arrives.

We did have an interesting learning experience, having encountered a bent caliper carrier. I don't recall having encountered this issue before but after struggling with bleeding and concluding that all air was cleared, we began looking for another cause for the inability to obtain a firm lever.

The symptoms of inability to pump up to achieve any significant pressure seemed like either significant air or damaged master cylinder primary cup. I had another master cylinder so a swap was tried but with no better results.

Some careful inspection while applying the brake showed some angular movement of the caliper to the mount. Measurements, eye balling, we tried swapping the adapter plate and pads with known good ones. There was no improvement so we swapped the caliper support bracket which cured the symptoms. We spent some time in comparison and measurements, then succeeded in correcting the distortion. One clue was the "bruise" to the bottom of the lower piston housing.

As soon as the new 250 Ninja master arrives, Mike will also be capable of stoppies.

Measuring braking distance was quite a challenge, and still one in which we lack confidence. Stopping from a marked point seemed most workable so we used 40 mph and repeated tries. The stock KLR seemed to require about 54 feet while mine consistently made stops in 18 feet. Please note that this should not be equated to published stopping distances since there was no reaction time involved. I think that the best which can be concluded is that the braking distance is very significantly improved.
 

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I figured out that I can change the sampling rate for the accelerometer app for my Samsung.

I will be home next week and will see if I can get some 40-0mph readings and send you the data file. Don't know if it will be off use, but it might at least be interesting.

Today I got to visit the Lapua .338 Magnum production line; a fascinating experience in how sniper ammo is made. Enjoyable, but I'd rather be tinkering with the KLR.

Tom
 

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Normk;402657) As soon as the new 250 Ninja master arrives said:
Normk,
I gotta' ask, How can a 'skinny' tired/dual purpose treaded, KLR with a single disc Front brake stop 40-ZERO MPH in 18 feet?

Do you mean 18 feet shorter? 54 minus 18 = 36 feet from 40 mph? This is still very impressive!
 

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Discussion Starter #14
I'm not certain about the value of the measurements other than they were duplicated several times. The only real value, IMO, is as a rough comparison with the about double distance by the stock Gen1.

Many variables including perception of the braking marker and difficulty in keeping at speed. One aspect is that many braking tests include reaction time but after many tries, the clamp was taking place as consistently at the mark as possible.

I do think that we should have tried some comparisons with phone accelerometer app. but time and the nuisance factor of playing with another set of issues made that seem too much nuisance. Next time Mike comes we will see what can be done to produce some more valid numbers. I was quite torn as to whether to even include that 18 feet as it seems too short to be credible. Perhaps simply that the E700 Shinko was starting to squawk, the rear tire as off the ground indicates something of the degree as have never been able to achieve anything like that with a stock system, even with 100 pounds of lever clamping force.

I could feel the rear of the bike beginning to try to pivot rather than the sensation of the rear tire sliding around as when a tire is sliding on the pavement. It became a bit white knuckle repeating that over and over because of concern with losing control of the pivoting and/or locking the front completely and having the front wash out.

Mike has an EM fork brace so am anticipating replacing his master cylinder to try to compare fork action under braking. I can feel mine curving under the strain and that the left one is bending more than the right. I'm very glad that the braking doesn't take place under fork extension because I'm more than wondering about a fork tube failure.

The skinny KLR forks are not confidence inspiring under that braking effort.

If I have ambition enough it would be interesting to put the Kenda back on for comparison but given the Tubliss system in the front tire, it seems like it may be more trouble than willing to undertake. Maybe Mike's conventional set up would be more practical. I do wish someone else around here was the least bit interested in this stuff.

Oh, one additional factor which keeps popping into mind as regards braking is that the practice included in the repeated tries has likely skewed the results so much that comparison is less reliable. After ...what?....30 panic brakings, the technique is much better refined than at first which may have made more difference than expected. It does speak to what we frequently advise one another but know that few actually do: practice maximum braking under various conditions and do it frequently.

I thought I was doing quite well with mine but became better when really at the task. I did find that having Mike standing by to pick up the pieces made me able to take more maximum braking risk that would have done solo. That's a factor I will keep in mind.

Paul, what bikes would you use as comparison? Anyone?

I have looked for figures but find 40 mph not that popular. We felt that 30 mph provided much less interval so made differences in timing even more critical and could not do higher because of speed limit. To do 60 mph requires highway and not wanting to be doing that out there with lots of traffic. It is too far to be going to more deserted highway.
 

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Normk,
I'll not suggest any other bikes for braking comparison. I do not know just 'how' the cycle magazines do their testing. I do not know just exactly 'How' you did your testing.

But if you have trimmed even 10 feet of distance off of Your Stopping Distance, from 40 MPH, on Your bike, with you riding it, that is very significant!

The "OLD rule of thumb" used to be about 30 feet from 30 mph.
120 feet from 60 mph. So Quadruple the distance at double the speed. Double the distance at half again the speed. Modern tires, modern brakes, should shorten those distances. If Not, Ya' Need To Practice!!

I just very recently had a 'braking' discussion with a Motorcycle Safety Foundation Riding Instructor! Who happens to be my Parts Unlimited Sales Representative. I suggested to him that the MSF should raise their braking test to a, 2 part test. 30 mph and 45 mph, to illustrate the required distance increase, for final grading of MSF course. Most Parking Lots do NOT have enough room to do a 60 mph test, riding a 250cc or smaller bike.

So using the old rule of thumb, 30 ft at 30 mph. 60 feet or less at 45 mph, or FAIL the MSF course.

18 Feet from 40 mph, After subtracting 'reaction time' is fantastic.
I am fairly proficient with the brakes on various bikes, new, old, oiled, neglected, bent, non-existent! I'm still alive.
18 Feet of Actual Braking Effect, 40 mph to Zero is Fantastic. Just proves my suggestion to ALL, Practice, Practice, Practice. Yes, it can get a little scary!

Better scared Now, than Dead Later!
 

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I think that you will find that the 338 Laupa has superior acceleration and stopping power to the KLR. ;-)
Indeed! :nothingtoadd: And that made me chuckle.
 

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"It is truly an effective round", Tom fired off.

Tom
 

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Discussion Starter #19
I agree with the need for better braking standards for MSF courses. They do quite a good job within the constraints. When things get really ugly, it's stop, maneuver or bleed.

Next visit, Mike and I will put our heads together and see if we can improve the methodology. I think the only practical way will be a phone app. because of the problems in marking stops.

It was a good start, regardless. Perhaps someone has experience in gathering numbers? I've not known of braking tests on a dynamometer for testing bike brakes, cars yes, but don't like the idea of trying that with a bike.



Normk,
I'll not suggest any other bikes for braking comparison. I do not know just 'how' the cycle magazines do their testing. I do not know just exactly 'How' you did your testing.

But if you have trimmed even 10 feet of distance off of Your Stopping Distance, from 40 MPH, on Your bike, with you riding it, that is very significant!

The "OLD rule of thumb" used to be about 30 feet from 30 mph.
120 feet from 60 mph. So Quadruple the distance at double the speed. Double the distance at half again the speed. Modern tires, modern brakes, should shorten those distances. If Not, Ya' Need To Practice!!

I just very recently had a 'braking' discussion with a Motorcycle Safety Foundation Riding Instructor! Who happens to be my Parts Unlimited Sales Representative. I suggested to him that the MSF should raise their braking test to a, 2 part test. 30 mph and 45 mph, to illustrate the required distance increase, for final grading of MSF course. Most Parking Lots do NOT have enough room to do a 60 mph test, riding a 250cc or smaller bike.

So using the old rule of thumb, 30 ft at 30 mph. 60 feet or less at 45 mph, or FAIL the MSF course.

18 Feet from 40 mph, After subtracting 'reaction time' is fantastic.
I am fairly proficient with the brakes on various bikes, new, old, oiled, neglected, bent, non-existent! I'm still alive.
18 Feet of Actual Braking Effect, 40 mph to Zero is Fantastic. Just proves my suggestion to ALL, Practice, Practice, Practice. Yes, it can get a little scary!

Better scared Now, than Dead Later!
 
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