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Front Brake Performance Drz400SM

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I have a 2013 with 11500 km on it. I notice I need a lot more pressure on the front brake lever and the stopping power is down.

Fluid level is good and no leaks. What type of brake pad life should I expect. Any ideas of something is wrong?

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you can physically see if the pad material is gone .. two things usually are the problem with a weak brake, either the disk got contaminated with something or they have air in the line .. wipe the disk down with mineral spirits or similar, and bleed about half a bottle of new fluid through them .. go from there ..

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I also found the standard lever adjuster is too short, and it took a lot of lever movement to actuate the piston in the master-cylinder. The brake was essentially very good. It just had alot of 'travel'

 

So i simply got a slightly longer bolt, rounded off the piston end to a nice round ball (Same as the stock part) and BINGO !

Just make sure if you go this route you have some free play, you don't want the piston always depressed some, otherwise you will have a "bad time".... To say the least.

If you braking has changed you need to find out why.

Lots of people neglect brake fluid. It should be changed every 2 years at a minimum. It absorbs moisture from the air, so you should always buy the small bottles of brake fluid, as you can't keep it stored, as it will go bad. If your brake fluid is containmenated with moisture it will perform poorly, especially during hard stops when the fluid is warm. Brake fluid should be clear, if your's is black it's toast.

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I would replace your stock rubber brake line for a braided 1 while your at it, that will greatly improve your brake feel, it'll be far less squishy, a HEL brake line is under £30 & well worth it, you even get some stickers & who would'nt want some cool lookin stickers that sat HEL on their bike  :D

Edited by carlspeaky
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+1 on this.

 

I also found the standard lever adjuster is too short, and it took a lot of lever movement to actuate the piston in the master-cylinder. The brake was essentially very good. It just had alot of 'travel'

 

So i simply got a slightly longer bolt, rounded off the piston end to a nice round ball (Same as the stock part) and BINGO !

 

P1020063_zps3afcbbbc.jpg

Beware .. When you do this , you need play at the lever . Where the Lever contacts the piston .

Yeah .. A clean disc and pads , fresh fluid .. ALL the air pushed / drawn out of the system .

A Steel line improves braking .

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I would replace your stock rubber brake line for a braided 1 while your at it, that will greatly improve your brake feel, it'll be far less squishy, a HEL brake line is under £30 & well worth it, you even get some stickers & who would'nt want some cool lookin stickers that sat HEL on their bike  :D

 

May be because you changed the fluid too. 

 

IMO, no need to stell/braided whatever lines. We have 2 DRZ here and mine has braided lines. Other is stock brakes. Pads are same model of EBC. And my rotor is in little worse condition.

 

DRZ with stock brakes is really impressive and slightly better than mine(bec. of rotor I think). It bites very well, power is good... Which shows stock brake system is good enough for bikes are 7~8 years old like ours (20.~30.000 km, maybe more).

 

So, braided lines may make it better -or it is just how we feel, not in real- but no need them for good brakes. Just change your fluid and clean your caliper+pads carefully this time. If it continues, than look for caliper seals or master cylinder.

 

Maintenance keeps brakes in good conditions  :thumbsup:

Edited by Syanur

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Just to add...reverse brake bleeding works very well for expelling air from the line

ye i found that out on the rear of mine after buying a new master coz i thought my old 1 was shot then realised its just a bastard to bleed normally  :facepalm:

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May be because you changed the fluid too. 

 

IMO, no need to stell/braided whatever lines. We have 2 DRZ here and mine has braided lines. Other is stock brakes. Pads are same model of EBC. And my rotor is in little worse condition.

 

DRZ with stock brakes is really impressive and slightly better than mine(bec. of rotor I think). It bites very well, power is good... Which shows stock brake system is good enough for bikes are 7~8 years old like ours (20.~30.000 km, maybe more).

 

So, braided lines may make it better -or it is just how we feel, not in real- but no need them for good brakes. Just change your fluid and clean your caliper+pads carefully this time. If it continues, than look for caliper seals or master cylinder.

 

Maintenance keeps brakes in good conditions  :thumbsup:

maybe the fluid might of played a part also but what i do know is that was a night & day difference after fitting the ss braided line & they dont use em instead of rubber on performance machines for no reason

Edited by carlspeaky

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Aftermarket braided lines make a huge difference at the track.

 

Good fluid with a good bleed helps as well.

 

I get a firmer lever and better feel even after things start to get way hot.

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For anybody who will get braided lines, be careful about chinese/fake lines. There are tens of chinese bike I have been seeing which came with steel/braided brake lines as stock.

 

My previous bike has one. Which shows they can make it cheaper but I am not sure for the performance...

Edited by Syanur

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in addition to fresh oil , new pads and braided lines there are two other cheap upgrades.

first upgrade is free: to get the max stopping power the screw on the lever must be parallel to piston while braking hard.  compared to a lever too far or too near the handlebar, power increase can be really noticeable.

2nd cheap upgrade: install a 11mm master cylinder coming from a 400e. it gives more power without too much travel at the lever.

i don't know why sm an s come with a 12.7mm master cylinder, our caliper was engineered to work with a 11mm master cyclinder. in fact most of bikes selled with our caliper has a 11 mc

Edited by 30x26

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2nd cheap upgrade: install a 11mm master cylinder coming from a 400e. it gives more power without too much travel at the lever.

i don't know why sm an s come with a 12.7mm master cylinder, our caliper was engineered to work with a 11mm master cyclinder. in fact most of bikes selled with our caliper has a 11 mc

I didn't care for the E master cylinder, didn't really seem that much different to me. I ended up using a master cylinder from a CBR, ~17.5mm and got the feel I was looking for.

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i do not get any feel from a lever with really short travel and probably less power, tastes are different :)

a 17.5mm mc is engineered to work with 2 calipers (much larger surface of pistons).  i'm sure you really like it but from a technical point it's way too big for our caliper.

compared to stock 11mm gives 15% more power, and more modulation

Edited by 30x26

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i do not get any feel from a lever with really short travel and probably less power, tastes are different :)

a 17.5mm mc is engineered to work with 2 calipers (much larger surface of pistons).  i'm sure you really like it but from a technical point it's way too big for our caliper.

compared to stock 11mm gives 15% more power, and more modulation

 

The other factor people don't take into account normally with this stuff is the leverage the lever has either though (and larger master cylinders tend to have a pivot point that allows for more leverage as well). I tried braided lines first, then the E master cylidner, still found my brakes lacking. The 17.5mm master cylinder with a DRZ lever gave me the feel and power I wanted. Granted I'm not a small guy, and the lever is firm, you really need to mean to pull it. However that was exactly what I was after. However then I tried a CBR lever, and it was like having power brakes again. Crappy soft feel, excellent brakes, just the lever felt so soft compared to the DRZ lever, all on the same master cylinder. 

 

I had this master cylinder laying around so it was free anyways. Otherwise I would have went with a radial version instead. However for free, it's been a great modification.

 

*edit*, Just for clarification I'm not disagreeing with you. It's just my personal preference.

Edited by OhioYJ
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I think our calipers have working/design range about master cylinder. Like they give good perf. between 10~13.5mm master cylinders.. So there should not be problem with using 12.7mm instead of 11mm E master cylinder. Otherwise producers will not chose this.

 

Because S and SM models are used more and more on asphalt, which requires stronger braking, they come with 12.7 mm cylinder instead of 11 mm. I think you felt better with 11mm cylinder may be it has pistons and seals in better condition. It doesn't make sense changing cylinder from 12.7mm to 11.mm and getting better braking performance. We can't change the physic rules :)

 

I do agree with lever/screw position and angle  :thumbsup:

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phisic rules say that, all other parameters being equal, a smaller master cylinder genetates more power :-)

sport bike master cylinder are larger because their pistons area is almost double. in fact their master cylinder area is almost double:

12.7 = 126mm2  17.5=240mm2  

 

ohioyj , you are right. lever length and pivot position are as important as master cylinder size.

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The other factor people don't take into account normally with this stuff is the leverage the lever has either though (and larger master cylinders tend to have a pivot point that allows for more leverage as well). 

 

 

You are correct that this often gets lost in any discussion about master cylinder sizes...  It is easy to just think about the volume of fluid and if everything had the same exact lever ratio, it would only be about the piston size.  The lever ratio is a very big factor as you look at alternatives to the stock master cylinder.  I fitted a Katana 14mm master with the stock caliper (before going with a 4 piston caliper) and it worked very well.  Pretty quick and easy upgrade for a road going SM.  It may be too much for a bike in the dirt, but great for a SM.  

 

There are certainly some combinations that will not provide a good result so you have to be careful...

 

You can see in this photo the distance from the pivot to the point that contacts the actual piston in the master cylinder.

The stock DRZ is on the left.

Brake%2520levers.jpg

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You can see in this photo the distance from the pivot to the point that contacts the actual piston in the master cylinder.

 

we can see that the katana lever, being the red distance larger, gives less mechanical advantage.

the distance between first finger and pivot point is missing. knowing that distance and red distances, we would be able to calculate if this mc produces more or less power

Edited by 30x26

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