[mitchb]

Hey all,

Wondering if any of you have tried an alternative front brake master cylinder? I'm a bit over the terrible brake feel and am wondering if a different master cylinder would help? after doing some track days at Eastern Creek it's getting pretty bad even after bleeding, and my rotors a bit warped too so i might look at all alternative for that too.

I know @philcuore has upgraded too the brembro rcs 19 but they're a bit more than i'm wanting to spend. There's some cheaper alternatives on ebay out of china but who knows whether they'd be any better than the stock items, I might try and find a used stock brembo one off another bike

 

[Bender]

Please keep us updated on your impressions. I also may be interested in doing such upgrade. They have already changed it as warranty and I have done only 800 kms!!!

 

[mitchb]

@Bender what was the problem with yours that it needing replacement? I need to get some warranty work done on the electronics/cooling system next week so might try that too, would rather that then spending too much more money on this bike

 

[Dan1]

If your looking at Brembo then go the RCS15, I was schooled recently on Brembo and the 19 for street is major overkill.....its true Phil
If your getting one from another machine make sure its single caliper, there are a fair few aftermarket options. Just remember the money you spend is what you get, its hard to say where the Duke pressure is being lost but something is causing it and Im guessing its the MC.
My disc has a warp in it as well, Ive been wondering if I should try warranty before replacement. If you do want to replace the disc Moose Racing do a decent priced option for front and rear as well as pads in organic and sintered. My preference for pads is EBC at the moment.

 

[Bender]

@Bender what was the problem with yours that it needing replacement? I need to get some warranty work done on the electronics/cooling system next week so might try that too, would rather that then spending too much more money on this bike

I was loosing braking power and the brake lever was touching the handlebar in order to brake hard. They bleeded the front brake with no major improvements, so they decided to replace the lever, and I guess, also the MC.

As there is a legal action against them, they didn't want to admit there was a faulty part, but I'm pretty sure the brake lever was replaced. Not quite about the MC, but it doesn't make sense it was fixed just with a new lever.

 

[Dan1]

Mark everything with a coloured dot, make the mark so small no one will pick up on it then when the bike comes back check it. I have tiny marks on places like the valve cover bolts etc, its not that Im untrusting its just that I dont trust mechanics

 

[HazardousDuke]

Mark everything with a coloured dot, make the mark so small no one will pick up on it then when the bike comes back check it. I have tiny marks on places like the valve cover bolts etc, its not that Im untrusting its just that I dont trust mechanics

Not a bad idea, even better if you make it look "OEM" which means making it look perfect. Do able and good "eyes" to have for you.

 

[Dan1]

Bit of an update to this, Ive been looking for a change out option without breaking the bank and have finally found one. One of the guys on the KTM forum is switching their 690 front MC over to the Brembo15 (occasional track days etc) so Im buying the Brembo OEM one from him. Should be a simple swap and will solve the problem hopefully.

 

[mitchb]

@Dan1 let us know how it goes i was looking at the 690 one as well

 

[mitchb]

I noticed the adac 390 cup bikes are running a 320mm front rotor, i had a look online and it's similar to one they currently sell as a powerpart for the 690 except the current version has a 5 bolt pattern where as the 390 rims require a 6 bolt. it's hard to make out the part number from the photos but i think it might be 90809960000 which isn't showing anything online atm. will be interesting to see if this comes out as a powerpart when they release the rc390. Should help get a bit more braking performance out of it

 

[philcuore]

Dan1 ... agree .. but i'm using a bigger piston .... Brembo Caliper and not stock Bybre ...

If your looking at Brembo then go the RCS15, I was schooled recently on Brembo and the 19 for street is major overkill.....its true Phil
If your getting one from another machine make sure its single caliper, there are a fair few aftermarket options. Just remember the money you spend is what you get, its hard to say where the Duke pressure is being lost but something is causing it and Im guessing its the MC.
My disc has a warp in it as well, Ive been wondering if I should try warranty before replacement. If you do want to replace the disc Moose Racing do a decent priced option for front and rear as well as pads in organic and sintered. My preference for pads is EBC at the moment.

 

[philcuore]

i have one of those ... for front and rear ... it's Snake Bite !

I noticed the adac 390 cup bikes are running a 320mm front rotor, i had a look online and it's similar to one they currently sell as a powerpart for the 690 except the current version has a 5 bolt pattern where as the 390 rims require a 6 bolt. it's hard to make out the part number from the photos but i think it might be 90809960000 which isn't showing anything online atm. will be interesting to see if this comes out as a powerpart when they release the rc390. Should help get a bit more braking performance out of it

 

[CWONG1]

Just got first service done 1111kms, wow,,,it's off the chain now....talked to dealer bout brakes...they said stock brake lines where a little budge .... rubber only causing them to expand under pressure....replacing them with HEL lines would tidy it up....????

I also had bikes usually with twin front discs, and wonder if this is the difference of breaker performance???

 

[Dan1]

Im just gonna say it straight up, the dealers a tosser!
The bike comes with braided lines already it just has a rubber outer sleeve, if he ran his fingers across it he would have felt it. Their not top shelf like HEL or Venhill but their good enough. Im sticking with my prognosis that its the Master Cylinder, if Im wrong when I get my hands on the 690 replacement I will let everyone know.

 

[CWONG1]

I thought lines where braided when I felt..but being newb...wasn't sure...
But convinced now...dealer is a tosser...will keep an eye out for master cyclinder updates

 

[mitchb]

still on the hunt for a 320mm rotor option, i have some ebc double h pads and still looking for a reasonablly priced master cylinder

 

[Dan1]

duke 690 rotor with a 20mm shim stack? Thats what they did to the RC.

 

[Bender]

Getting annoyed with the original MC's quality. Only three weeks after the bleeding I'm loosing stopping power again. Not critical but certainly noticeable.

Not acceptable in a bike with only 1000kms on the odo. We shouldn't be looking for any aftermarket solutions to have better brakes. Is KTM who MUST be issuing a recall to provide a decent MC

 

[mitchb]

the 690 has a 5 bolt pattern on the hub unfortunately, the 390 has a 6 bolt. I need to pull it off and measure the spacing and see if there's an aftermarket one out there if it's a standard spacing.

on the hunt for some spacers too but if i can't find some i can use a friends lathe to make some up. they'd be 10mm as the radius is only 10mm larger

 

[Mostin3]

Has anybody tried a different master cylinder yet? My front brake is absolutely awful. It's now got to the point where the lever is about 10 to 15mm away from the bars on full depression. No feel whatsoever and sponges as ****.