An 800's Rebirth/The build of MechanicO

Absolutely amazing skill

Did you ever get your hands on a GS911? PM me, I have one you can borrow!

PS; Amazing work on here. The skill on this forum blows my mind...

RandyReider,

Huge thanks for the offer but I did end up just buying one. Neat tool with some use full information for sure.

We did take the bike down and dyno it in its stock form for a good base line. Will get more into that later in this build thread.

Good to know. I never heard back so figured you had sorted it out somehow or other.

So time to come up with something as a temporary for the headlight. I have designed and modeled a really nice (and VERY bright) system but just want to through something on him now so he can pass inspection and ride if needed. I will come back and build the better system later. However, I will make the clamps for the fork now that will eventually be used for the final system.

So we are going to make 4 of these



They are basically the same except the top ones are slightly smaller due to the forks having a smaller diameter up top.

So make a print out of the part and lay down on some aluminum stock to create my blanks



Using the band saw make the blanks and mount the first one in the vice



Then cut the profile of the clamp but as you can see I leave about 3mm on the bottom of the part in the form of a flange. This flange is what allows me to hold it in the vice and cut an odd shaped part.



Now cut the inverse profile of the part in some soft-jaws in the vice



Now I can put the part back in the jaws (upside down) and plane off the flange




Now flip the part onto its side in the jaws and use the slitting saw to cut the slot so we actually have a clamp. Not shown is drilling the holes and tapping them for the clamp bolt.



Repeat 3 more times and we have our four clamps



I did not want metal on metal on the fork tubes and I also wanted some vibration isolation for the headlight assembly. So I used some 1/16" EPDM rubber that I cut into strips the width of the clamps




Then using contact cement I bonded them into the inside of the clamps. I will have to remove these when I get around to anodizing everything but that is easy with contact cement. I did account for the thickness of the rubber when I made the ID of each of the clamp. And I am using M8 bolts for each clamp.



Did not go into this part too much with pictures but I just used some scrap 1/4"x 1" aluminum bar to quickly make some mounts that will go onto the clamps I just made and then hold the stock headlight assembly. Again this is all temporary but will get me by for now.

Note: the rubber I used is just a tad too soft as is really squished out the sides of the clamp when I clamp down. Next round I will use a firmer rubber compound.



The custom radiator/cooling system is next. This is a big part of the project. More to come......

The original radiator did take a hit during accident. To its credit, however, it did not leak and still worked fine. But it was deformed, a lot of the cooling find where damaged, and all the plastic mounting for it broke. Which, or course, means the plastic mounts did there job and saved the radiator.

So my decision to make a totally new and upgraded radiator came from several thoughts:

• I really did not feel like using the one that came with the bike in the bad shape it was in
• My math showed if I did a bunch of the work and made a lot of the parts I could make it for around the same price as the stock one new
• I wanted to make the radiator not as wide as stock
• All aluminum radiator will look good on MechanicO
• And a pet peeve of mine: I do NOT like plastic in radiators

Side rant on plastic: Plastic is a fantastic material....when applied right. A classic materials quote is "There is no wrong material, just wrong applications". Plastic is great to hold my milk in one gallon containers, lawn chairs that cost $3.00 each, and a billion other consumer goods that all would probably not be here if not for plastic. But in a radiator? No way am I doing it on MechanicO. Putting plastic in an environment that is:

• Boiling hot temps
• Chemical coolant containing
• Under pressure (15-20 psi)
• And prone to impacts as they usually are placed in front of a vehicle

is wrong. Just not doing it. Also, you cannot repair them in the field (not totally true, you can epoxy them to an extent), aluminum you can weld back up. And they always weep coolant over time as they are not really bonded to the core but rather "crimped" on. They weep. And the last reason, plastic is a great insulator, compared to aluminum that is a fantastic radiator. I don't want insulating material on the tanks of my radiator. I get it, they are inexpensive and probably crazy cheap to assembly, but it ends there. OK, rant off

So of course I went to the computer and modeled up "Super Radiator" for MechanicO



I am sure the engineers at BMW did their research and made sure the stock radiator was the correct size for the job. So rather than me second guessing them I tried to model mine from theirs actually. For example:

• Their core is 1 1/4" thick with 17 core rows, so is mine
• The area of the core stock is 108 in^2, mine is 106 in^2

By keeping these dimension close to stock, I figured that was a safe start. Yes, mine is 2 in^2 smaller but with the all aluminum end tanks I figured we where not the same if not a little better.

Some other notes on the BMW radiator for reference:

• It is a double pass design. It splits the core in half height wise so the inlet and outlet are on the same side
• The bypass circuit in built into the right tank and is rated at 185 deg F
• Fan turns on at 223 def F and warning light comes on at 240 deg F
• The coolant flows into the lower section, pushes up into the upper section and returns to motor with the top radiator hose. FYI: This is opposite from most cars. I suspect one reason for this is to help purge air.

So with the split core design there is a divider between the 8 and 9th core row to make the right tank have two separate chambers.

Here is a more detailed drawing of the radiator showing the final dimensions



So one thing I did was make the core narrower by 2" as the stock core is 15" wide and mine is now 13". However, I did need to make it a bit taller to get the surface area back, so stock is 7.25" tall and mine is 8.15" tall. Over all I ended up being 2" narrow than stock which I really like as I am trying to "narrow" the entire bike up.

So the fan was in fine shape and totally usable and free as it came with the bike. Screw that. I wanted more because...well...why not. So I sized up a Spal fan that should fit perfect onto the back side of the new radiator. Some data:

Stock Fan: 5.20" diameter - 313 CFM of air
Spal Fan: 7.5" diameter - 500 CFM of air

That is about 60% more air movement. Yea-ha! I am a bit concerned the CAN-Bus won't drive the fan as it has a much larger draw but if not I'll put a relay on it. And these aftermarket fans are not expensive, this was about $80 compared to $265 for the stock one that I hear craps out now and then.

The two fans side by side



The Spal Fan part number I am using



So the next big hurdle was the bypass circuit for the radiator. For a quick lesson on this, it goes like this: When a motor first starts the thermostat is closed and blocks coolant from going through the radiator so the motor can heat up. However, you need a way for coolant that is warming up to at least pass by the thermostat eventually so it can activate and open when needed. So a bypass circuit allows for this. This is VERY important when you have a remote thermostat like ours on these bikes that is located in the radiator itself. Generally, like in cars, the thermostat housing is located on the engine block so it eventually gets heat from the engine itself. But with ours in the radiator separated by a rubber hose, it would take too long for the warming coolant to get to the thermostat and possibly over heat the engine before it opens. So our bypass circuit allows just a little coolant to flow through the entire system until the temps come up and the thermostat opens and away we go.

So the stock BMW radiator has the thermostat and bypass circuit built into the right tank of the radiator. I needed to simulate this but with the abilities and capacities I have. So I opted for a thermostat housing that will bolt to the back of the right tank and has an exterior bypass hose (the hose connects the two brass fitting in the first picture. To lazy to model a hose for this). And it will also use a small automotive thermostat that is used in about a ba-zillion cars on the planet so easy to replace on the road.

This is the basic design for the housing. I added a bunch of surface area via ribs because, er....more cooling and looked cool to. The 1/8 BSP port is for the Vapor dash temperature gauge. Good lord, why a BSP thread! Had to order that tap special.



So this project starts with making the housing. So we start with a god-awful chuck of aluminum. To the mill!

IIRC the ECU monitors fan current- if the Spal is too beefy, a relay may not help you...

dpm: agree, there may be some issues. However, what I do know is the ECU does in fact monitor the current of the fan to see if it fails or has an obstacle obstructing it. You then get a "warming" light on the dash in the form of one of the existing light (not sure which one). So if that is all this monitoring does, then there is a chance the Spal directly will be fine, but I would think for sure a relay would work as the current draw would be minimal and not "trip" the ECU. I'll test and report back.

Not sure if I am showing too much detail of the project? If this is moving too slow let me know and I can cut some of the detailed pictures out. Anyone...Bueller...Bueller....

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To make the thermostatic housing we need a crap load of tools. Here is who we have standing by in the mill. You can see the chuck of aluminum in the vice as well ready to go.



So the first op is to profile the mail part, drill some mounting holes, and put in some fancy radius and slot cuts. You'll notice I left about 6mm on the base of the part so we can hold it in the vice while cutting.



Now to do the back side we make some custom jaws for the vice to hold the odd shaped part and machine off the flange from the first op



With the flange gone we can drill and cut all the inside bores we need to hollow it out and accept the thermostat



Now roll her on the side and drill and tap the holes for the bypass fitting and temp probe



Then onto the other side to mill out a channel for the inlet tube so coolant can get into the housing (inlet). This was done on the manual mill.



To create the inlet tube I took a piece of already made 1" aluminum tube that already had a hose bean rolled on it. Cut it to length and add a taper on the end so allI had to do was made a small piece to "cap" the end of the tube



Here you can see everything together as far as the inlet and positioned on the housing.



At this point I had it all welded up and sent back to me. For the record I can weld aluminum. Can I make it look nice and guarantee it won't leak? Hmmmmm maybe. In cases like this I leave it to the pros. It just looks so good when done right.

So here it is back on the mill where I cut a O-ring channel and planed down the surface by taking off .010". I purposefully left this amount and did it in this order for one reason: things warp and move when you weld them. If I had cut this channel before welding there is a good chance the part would warp and the O-ring would not seat right and leak. Easy to just leave some material and do when it comes back. Water tight now! You also can see the thermostat in it's position.



And another shot of the bypass fitting and temp probe installed (before welding)



So now we need to turn the radiator itself. There are really only a few parts I need to machine for it and the radiator guys will take care of the rest. So those parts are next.

Got to love all this custom bike build porn!
Keep it coming Fin !

I'm enjoying reading about this, even though it's WAY above my skill set.

Indy Unlimited: read you profile. I am SO with you on the 300lb supercharged adventure bike. Big fan of Superchargers, so much so I made a supercharged Subaru. Small motor + big charger = torque and fun.

Yeah motorcycle companies keep going to heavier more powerful 600 lb adventure bikes which is the opposite direction. Lighter smaller motor with good linear power output like supercharging would make the ideal platform for a world class adventure bike. I really like the new KTM 690 for a platform with 120 HP supercharged output for such a project but custom building is for heroes like you.

Fin,

Look at you go.

Single handedly raising the standards on ADVRider.

Kind regards,

Scott

WOW!!! thats what i called SKILL!!!! amazing job

Nope. Don't leave anything out. This is good stuff.

I've been following along since you started. This is a great project, don't leave anything out! Quality work like this takes time and you are doing a great job! Can't wait to see how this GS turns out

Indy_Unlimted:

Did a little math and came up with this for a supercharged 690:

125hp = 13.1 psi of boost
100hp = 7.6 psi of boost

* based from stock 66 hp rating

As fun as 125hp would be from that motor you would definitely need an intercooler and a good sized one at that.

But by "just" going to 100hp you are under 8 psi of boost and could run with out an intercooler. Still might have to have the piston modified to drop the compression ratio closer to 10:1, but it would work.

Not to mention you would be talking a new stand-alone ECU running a MAP based system to compensate for boost. But all doable and off the shelf items in my book as far as engine control.

Driving the SC off the motor is the mechanical challenge. You have to come off the motor BEFORE the transmission. So I envision an output coming off either the clutch side or the stator side.

And how would the trans hold up to the 51.5% increase in power? Spin, wheelie, or explode I suppose are the three options.

Challenging for sure. But the torque curve would be outrageous and you are adding maybe 10-15 lbs in extra hardware. And the whine of the SC is always cool. Mad Max Fury Road baby!

Here is an idea.

http://www.vfrdiscussion.com/forum/index.php/topic/62726-a-a-performance-6th-gen-supercharger-kits/

Looks like a nice lightweight SC. No blower whine though.

Beautiful work Fin, look forward to seeing more!

Jeff