DIY LHRB that retains the foot brake


Philip

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Ann Arbor, MI
#1
I think I should re-post the DIY LHRB recipe, which is buried on Page 6 of The Alta Factory LHRB thread.

Here is the recipe:
1) Brembo clutch 9mm master cylinder KTM P/N 79202030044 from the 2017 KTM SX-F 250/350
2) Clutch hose KTM P/N 60032063100 from the 2014+ KTM Adventure (must straighten by 45deg at your own risk)
3) Clake slave cylinder adapter SLR – Pedal Master Cylinder Adapter Kit. Make sure the Clake adapter you receive has a 51.5mm overall length.

The hose has a 90deg bend near the banjo fitting. Ideally there should be no bend, although a small bend is okay. I put it in a vice and straightened it to only about 45 degree bend. That worked, until I installed it and then out of curiosity decided to straighten it a bit more. Well, it broke. Cannot straighten it more than 45 degrees. I bought another hose, straightened it only up to a 45 degree angle, and it is working now.

I have had my MXR out a few times, and the LHRB is working okay. It is not quite powerful for routine brake slides, but it works as well as any LHRB that I have tried.

The cost -- about $290 total with shipping.

IMG_20180721_2052345.jpg
 

OneLapper

"You don't *really* need the water pump...."
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#2
FYI, you can order a custom hose from Spiegler, pn EL-1330-001-410 which does not need to be modified. That part number is 1330mm in length, a bit long but allowed me to route the hose so it does not pull at all on the the upper bulk head. That eliminated the worry of the hose rubbing on electrical components. Cost was $72.95 plus shipping. This is for the above set up.
 
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24
Location
51399 Burscheid
#3
I think I should re-post the DIY LHRB recipe, which is buried on Page 6 of The Alta Factory LHRB thread.

Here is the recipe:
1) Brembo clutch 9mm master cylinder KTM P/N 79202030044 from the 2017 KTM SX-F 250/350
2) Clutch hose KTM P/N 60032063100 from the 2014+ KTM Adventure (must straighten by 45deg at your own risk)
3) Clake slave cylinder adapter SLR – Pedal Master Cylinder Adapter Kit. Make sure the Clake adapter you receive has a 51.5mm overall length.

The hose has a 90deg bend near the banjo fitting. Ideally there should be no bend, although a small bend is okay. I put it in a vice and straightened it to only about 45 degree bend. That worked, until I installed it and then out of curiosity decided to straighten it a bit more. Well, it broke. Cannot straighten it more than 45 degrees. I bought another hose, straightened it only up to a 45 degree angle, and it is working now.

I have had my MXR out a few times, and the LHRB is working okay. It is not quite powerful for routine brake slides, but it works as well as any LHRB that I have tried.

The cost -- about $290 total with shipping.

View attachment 760
Hi , we tried this converversion , its dangerous !!!!!! Why ? in this constellation the pressure of the System blows ot the view glass out of the Brakefluid reservoire, it comes out when you use both Hand and Pedal !!! have a look if it is sitting still well.
 

Philip

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Ann Arbor, MI
#7
The window will pop out ONLY if the O-ring seal is leaking. And ONLY AFTER the external reservoir gets filled with brake fluid, as it normally should never be full. And ONLY IF the fluid cannot leak out through the threads at the top of the cylinder.

There is nothing dangerous about the window's popping out. Even if this happens, you will not lose your rear brake, only the LHRB. You will mash the rear brake pedal instead. And you will still have your front brake.

The cause of this window's popping can be the seal installation, which is most common, or defective parts, which can also happen.

Clake once sent me an insert which was 4mm too short, which I caught before it caused any trouble. The master cylinder casting can also have a porosity that wasn't caught by Brembo, which is not very likely. I have never had the O-ring seal installed incorrectly, but I imagine someone can be sloppy when installing it, or not bother to look inside the brake fluid reservoir to confirm it is indeed installed.

The simultaneous application on both the LHRB and the rear brake does not double the brake fluid pressure at the seal or at the window. The foot pressure only increases the fluid pressure downstream from that seal, after the rear master cylinder piston. The leaky seal is subjected only to the LHRB pressure.

I fill the brake fluid reservoir only up to the middle of the glass window. If the seal ever leaks, I will see an increase of the brake fluid level in that window. That never happened in about 8 installations that I have done over the years. And I have mashed all three brakes in panic numerous times.

Rekluse and Clake have been making these rear master cylinder inserts for years and years. They had thousands of happy customers. If there was any inherent problem with this design they would have stopped making these inserts a long time ago.
 

Mark911

Well-known member
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452
Location
Corona Ca
#8
So far I've dome three conversions, each a bit differently.
1) Master with Rekluse insert
2) Welded OEM
3) Welded China import

They all work fine but #3 is by far the cheapest, about $25 (if you do the welding).

The only/best solution at the bars is the Brembo clutch MC. If you're lucky you can find on ebay for less than $50, otherwise it's typically over $150. Amazon has tons of options for hoses, you'll generally want a -3AN on one end and banjo on the other (or two ANs and an AN to banjo adapter) and about 48 inch length depending on how you like to route it. Cost, about $30.

Total, between $120 to $200.

The biggest difference is using the twin piston Brembo caliper. You can find these all day long for around $100 (including bracket, which you'll need). I made a cutting/welding jig to combine the stock caliper bracket with the larger Brembo caliper bracket and it only takes me an hour of so of fab time. The 240mm rear rotor is also a good improvement. Braking makes a kit for the KTM which includes a new bracket but it's over $150. I found that a Yamaha rear rotor is very close bolt circle wise, maybe 1/2 hole off. By "smowmaning" the holes and welding some stainless washers to the rotor it works great and can be found used for dirt!

Total with Twin Piston Caliper and oversized Yamaha rotor = $220 to $300.

Now you have a system that'll lock up the rear wheel with two fingers! I'm so spoiled that I added the same system to my ICE bike, right under the clutch. IMG_2992.JPG IMG_2995.JPG IMG_2990.JPG IMG_2997.JPG

IMG_2991.JPG
 

Mikec265

Well-known member
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104
Location
16412
#9
How much do these LHRB setups help in Whiskey throttle situations? Are they enough to save my ass when arm pump won't allow me to let off all the way?
 

OneLapper

"You don't *really* need the water pump...."
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756
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Connecticut
#11
The LHRB stopped my MX from looping out when my son was goofing around with the Alta in the yard. The rear fender just touched the ground! It stopped the wheel fast enough to nearly toss him over the bars when it came back down!
 

Motophyllic

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74
Location
NY
#12
I have 2 Clake slave cylinder adapters that I decided not to use if anyone needs them. I paid about $100 each I think. Anyone on here can have them for $60 each. Brand new.
 

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