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Discussion in 'Parallel Universe' started by FinTec, Dec 12, 2014.
Great stuff Fin, thanks for the fix!
The single rotor is enough as long as you change your master cylinder to one with a smaller bore. Since you're only pushing half as many pistons at the caliper (and they maybe smaller diameter than the factory F8 pistons) you need less fluid volume from the MC. If you use the stock F8 MC, you will have a very stiff brake lever and terrible braking. IIFC the F8 is 15mm bore. The F650 twin used a single rotor and same caliper as the F8 but used an 11mm bore MC. That's what I run with my single rotor/caliper set-up and the braking performance with it is much better than when I was running the stock F8 master.
Bear in mind that, over here in Germany, we can max out topspeed of these bikes. The 800GS does >200km/h, thats almost 130m/h. Taken the gross vehicle weight of 443 kg max (977 lb) that should give you enough reason for two discs, even if you´re not an attorney.
But you´re working on that last point I see. Keep it up!
We have both bikes and yes, it takes some adjusting when going from the 800 to the 650. Having just ridden the 650 for 14,500 kms overloaded, I was fine with the braking on the insane mountain roads in CA.
You wear out the pads twice as fast on a single disc tho.......
Elegant solution. Did that fall together for you, or had you planned it when you chose the 210mm fork spacing? That much unsprung weight saving ought to really help thru the rocks.
I guess you give up the ABS and simplify the brake line route.
Can you say, that spacer . . . did it move the wheel center laterally to the right, off the steering tube center . . . or does the wheel stay centered up?
Maybe this is asking a lot, but suppose you were to decide you want the two rotors. You'd need a hub with rotor mount bolt holes on both sides. The width and axle size would have to work. And the right side stanchion would need to mount a caliper unit. Impossible?
I don't see why ABS has to go. If he can fabricate an adapter to attach the ABS ring to the rotor bolts, and a mount for the ABS sensor on the fork, the system won't notice anything different. I say it like it's an easy thing. Definitely above my skill level, but this dude can whip up an entire bike from his CNC mill.
Right, there's the ring, and the sensor to remount. And one brake line to eliminate. That all seems easy enough.
But you'd expect hydraulic pressure in the system is going to be different now . . . and the electronic brain in the ABS controller that senses inputs and adjusts pressure to the calipers. . . it would have to be adapted to that. I dunno. Sounds like it takes a trained tech and some experimenting.
Maybe its not all that hard.
With the KTM 4860 forks, a KTM front wheel with sensor ring is easily available. RAD manufacturing makes the hub. OEM ring is similar if not identical in design, just different bolt pattern. The 2014 690 comes stock with ABS and I tossed the sensor and ring. Strictly for scientific reasons I would part with the parts to continue Finn's artistry.
OK, some answers to questions and comments:
Camel ADV is correct, you do need to match the MC to the new Caliper. MotoMaster does give some recommendations and I went with a Magura MC with a 12mm bore. Very clean and simple set-up as the reservoir bolts right to the side. No more "bobble-head" reservoir. And the lever action is VERY nice. I'll try and get a picture of the MC soon.
100% agree Freerk. If I was going to run the auto-baun 2-up and full luggage, I would absolutely keep the dual fronts. But for the purpose of this project my logic goes like this:
If I go over 80 mph, I am going too fast.
I never ride 2-up and avoid it at all costs. As a matter of fact the rider pegs come of this project bike.
The goal of this bike is off-road.
If I am in Germany (again) on the auto-baun, I'll be in a rented Audi RS
So my point is intent. I have no need for dual disks and every reason to remove it for this application. My heroes here are the OSO Loco guys who have many ride reports here. They are doing amazing technical off-road in the reports on big, luggage-carrying KTM950/990. However, look at the majority of the front ends: they have all switched to large single front rotors from the factory dual. They know (and prove it!) that if you want to increase your off-road ability, drop that un-needed weight from the front end. It will handle like a ballerina going 6 MPH in that rock garden.
97707: the wheel spacers are what center the wheel between the forks. However, since the caliper is mounted to the fork leg and it is now 10mm farther out (difference between the 190mm and 210mm fork leg spacer on the triples clamps) that spacer in the picture just moves the rotor back in line with the caliper.
So let's finish up the front end and make the risers and bar clamps.
First, went with a nice set of Renthal "Fat Bars" in the "KTM High" model. I knew I wanted a good amount of rise in the bars and so what I did was literally stand on the pegs, hold the un-connected bars in my hands, and hover them over the top triple clamp until it felt natural and just "right". Then I had a buddy measure the distance from the bars to the top triple clamp and designed around that. Standing performance is what I wanted and sitting was secondary to this. So at my 6' 1" height I came up with 40mm rise, but I had 10mm built into the triple clamp so total rise compared to stock was right at 50mm.
So started with making the risers them selves. I thought about integrating the lower clamp and risers into one unit but I wanted the ability to change the height if needed.
This is kind of where the theme on the bike started. I grabbed some brass to make these as you just don't see enough brass on adventure bikes in my opinion. So here is the bar in the lathe
Finishing up the through bore for the bolt as well as making the "cup" for the stock rubber bushing and washer. The "ribs" are for increasing the surface area so they stay cooler. If you have ever seen a bar riser over-heat it is not pretty.
Picked the part off the lathe and put it in the mill. Here I did two things: drill a series of holes only to lighten it up. Damn this copper is not light. And I added two chamfers so it looks smoother when aligned with the clamps
Now set-up the mill with these tools to make the lower clamps
Start with a clean bar of aluminum in the vice
Them make the profile, through bore, radius the edges, and a nice pocket for looks and weight
Flip it over and do the same on the other side
Remove the part from the clamps and cut the top off down the middle of the bar bore with the band-saw. I cut it a tad higher than needed so I could go in and finish to the height I wanted. And you never want a band-saw finish on your final part. Looks shabby.
Back in the vice to drill and tap for the clamp bolts and then drill through and make a counter bore for the large M10 bolt that attaches them to the top triple clamp.
Flip over and drill a single hole in the base. This is where a pin will go to align it with one of those holes in the brass risers. Model it!
And here is what we have so far
Some notes: I made the lower clamps with an offset (you can see it from the side). I believe it is a 10mm offset. This will allow me to mount the bars either 10mm towards me or 10mm away from me just by flipping the clamps 180 degrees. For now I am running them 10mm towards the front. I like the brass look and get ready to see more of that. Next, the upper clamp.
Upper clamp was a little more work that I was thinking. It needed a lot of ops to set-up and you needed to make sure they all lined up. So we started with a nice piece of 6061 T6511 alum in the vice. Here I am just taking down the ends to make the blank square
Next we put the blank on its side and machine the bar profile.
One thing I learned on bar clamp is you under size the bore for the bars. This "pinches" the bars when you clamp down and really holds them in position. Here you can see me taking the stock bars and putting int he bore I just machined. See how the bore is slightly less than the bar diameter
Here we are after doing both sides of the blank
Then we machine the holes and counter bores for the mount bolts
Then we take a another piece of aluminum and make a fixture with the same patter as the previous mount holes with threaded holes
So no e can mount the blank onto this plate with some M8 bolts
So we can now machine the entire profile of the upper clamp here
Flip it on it's back and machine the underside
Then clamp on its side and drill and tap the holes for the hand protector bars and dash mounts
DONE! Here is the entire clamp system on the bike. as you can see Emma is beside herself with excitement
Then I cranked out some simple brackets to take the Vapor Dash from Trail-Tech and also mounted the RAM mount for a the Garmin GPS. That is the small M5 threaded holes are for on the top of the clamp
Came out really nice and just as I had modeled it on the computer. Lots of adjustments in the system and a nice clean look. Next we make the hand protector bars with some "brass" bar end weights.
Random side question:
Shopping for rear shock (the TT is high on the list). Does anyone know what the stock spring rate is for the rear spring on 2013+ 800's?
I looked/searched high and low with no luck :huh
Last year I asked my BMW dealer for the spring rate of my 700 and he was unable to answer me...
Sick man, that's just sick!
Did you take the rubber grommets off the riser bolts? As tall as your bars are, you might have KTM bolt failures similar to the OSO's.
He said earlier he cupped the brass risers for the stock rubber bushing.
Dang, still have not been able to get an answer to this. I even asked TouraTech as I plan to order the rear shock from them, and they did not know :huh
I'll keep looking....
Great question! I did think about this but came to one conclusion: there is a huge difference in the design of the ones in that thread and the ones on the 800. Take a look at this diagram
Notice item #10. This is the steel "stand-off" that goes inside the rubber grommets. This allows you to actually torque the bolt down and put it is tension. Tension is where it gets its strength. The one in that thread has no "stand-off" and the bolt never sees tension. That is why they replace the rubber bushings with aluminum ones, so they can actually tighten down the bolt. Honestly, that is a pretty poor design, but easy and inexpensive so I understand. Of course those OSO LOCO guys are just plane nuts
Now to the hand guards. Sticking with my brass theme we start with that material for the end clamps. Couple of thoughts here: good news with brass is it is WAY denser than aluminum and with less material I can still have some mass on the bar ends for vibration control. Also, I am not a fan of the designs where there is a bolt head sticking out the bar end. Looks crude and if something bad where to happen, I don't want a bolt head embedded in my chest. I actually took a bar end to the chest once on a mnt bike. You want that bar end as blunt as you can make it. So I came up with a design that will flush the bolts head and capture the entire aluminum bar so it looks clean.
Start with making a counter bore in some brass bar
This will capture the expansion nut that goes in the bars themselves
Then turn the outside down and add some grooves (again for cooling as bar ends can heat up) and to add a holding spot for the very high-tech O-ring throttle lock I learned about here on ADVrider.
Testing the O-ring
That gets picked off and now we are making the "cap". The key here is to make the OD the same as the main body we just made. This will make the seam VERY hard to spot once assembled. Added more ribs for cooling, of course, then pick it off
Now take the main body to the mill
And using a 3/4" EM we cut a channel in the back side of the body like so. This will all make sense once we assemble down below
So here is the kit I made for the hand guards. Right now using Bark-Buster plastic (might change that later on) and some 3/4" x 3/8" aluminum bar.
Now this is where the back and forth starts. You just can't do the math for this or model it. WAY too many angles and bends to make it worth while. I call this sculpting at the point. So what this entitles is dozens of trip back and forth from the bender to the bike to see how I am doing. Keep doing this until I get the bend I want. This is called a Diacro Bender (actually this is a cheap China knock off) that is fantastic for bending bar type material. So here is a progression of shots as I bend and check on bike
Once I have the final shape I mill a slot in the inside end to mount to the upper bar clamp we made previously.
Came out very nice. You can see the O-ring throttle control as well. As I hoped the seam for the brass cap to brass body is so alighned you cannot see them. People who have seem it ask how I cut the "square hole" for the aluminum bar
Side rant: I am NOT a fan of these hand-guards that include a clamp for the bars that looks like an erector set gone mad. I had to put one of these on a friends bike once and it was a bag of parts and bolts that never seemed to end. Just not clean and simple in my opinion and not to mention a stack of more screws you have to make sure stay tight. Keep your cockpit clean! Rant off.
I think the next installment with either be the new headlight assembly or the custom radiator and cooling system. I have to leave town for 10 days so more when I get back. But as always, here to answer question if you have any.
So I'm. curious about the galvanic reaction that will happen with the brass / aluminum / stainless combination. Aren't you worried about all your nice work corroding away? (assumed a stainless bolt)
I just got a new spring (not installed yet). Suspension shop measured my 2013 stock rear spring at ~15kg/mm, which matches what Racetech claims for the older bikes:
FWIW, I'm ~215lbs before gear, ride solo, minimal luggage and the shop wound an 18kg/mm spring. He said he would have gone stiffer, but was afraid the stock shock wouldn't be able to cope.