Lots of orange about!! 



and a new dash from Translogic.

I finally got around to fitting the filler cap-much better.



....and before anyone mentions it, "Yes I know the tank needs wet-flatting and polishing!"

Man this is awesome.

Loving it a lot! Cant wait to see it!  Also like the look of the airhead you sold.

Anyone know where the real Cobas bikes are these days?

floyd wrote:Man this is awesome.

Loving it a lot! Cant wait to see it!  Also like the look of the airhead you sold.

Anyone know where the real Cobas bikes are these days?

Thanks.
I do have sellers remorse when I think about my twin. 

I've tried so hard to find where the original bikes are (there are 2) but to no avail.
On one line of enquiry I was given the email address of the well known journalist Alan Cathcart. He'd ridden one of the bikes way back....read on.

Hi Alan,
I hope you don't mind me contacting you but this picture I've attached of you has started me on a journey......
Having seen your picture riding the Cobas BMW K100.I thought it would be good idea to build a replica (as near as I could get) of the bike.

I was wondering if you could remember what it rode like,was it quick,did it handle OK,how much development went into the engine etc. I'd be grateful for anything you could remember but understand it's a fair while back.
I also would like to ask if you have any information on the bike's present whereabouts and where it was built? The hardest part to get right is the fairing and I'm sure that the mould still exists somewhere in Spain. I've asked and emailed so many people but not managed to gain any useful information so far.

The bike has been accepted,on the proviso it looks correct,to ride at the Bikers Classic at Spa in July so I've still got lots of hours to put in before then. The engine is running and I did a track day at Cadwell last Friday and it performed well for an 80's heavyweight but it will need to go for the fueling to be mapped as it's all over the place due to some engine modifications. Time is running short!!





[size=15]Hi, Mike,
 
Sorry, but I have to stay right out of this.
 
The owner of the bike today (actually, of both such bikes made) has a very negative take on replicas of the bikes in his collection. Therefore, I’m afraid I cannot do anything to help you in this project.
 
Alan Cathcart


...so it's a dead end for now.[/size]


Thanks Alan !

I turned up this image of the bike in endurance trim and as I will occasionally ride it on the road,a light bracket was made from aluminium.







I'm about to finish the bracket now and make a sub-loom.

To try and keep the bike as true to the Cobas bike as possible,I've changed the rear end for an early Mono set up. As one alteration creates another ten,I've had to make another exhaust system because the Mono swing arm is 40mm shorter, the back wheel touched the link pipe. 
I've used K1200RS headers that are 4mm larger in diameter but had to modify around the lump above the gear lever.



The bodywork is painted but needs decals.

good tip about the k1200 headers mike

that should make it flow a little differently 

still stunned that the k1100 headers  are "fixed in place" manifold adaptors ...and the short curved # no 4 pipe doesn't enter at the same angle as the rest ....no wonder that they crack along the length

keep at it

What triple clamp is that?


Bike is looking awesome mate.

It's a stock K100 16v item. I welded some thin plate on to cover the holes.

Great basic write up of the JJ Cobas K bikes (link)

Also includes the interesting fact that the (ive never seen it called this anywhere else) BMW CDS (Compact Drive System [engine, gearbox, drive shaft, final drive]) only weighs 76kgs dry. 

Says they wrang 122hp @ 9400rpm out of it. Wonder what was done to the engine. Also says a custom EFI system was used....but failed on debut. Would be interesting to know details.

Hi Floyd,
Thanks for that. I'll read it tonight,better still,I'll buy the book!

Just back from Spa.
The Bikers Classic should on everyone list of things to do. The classic 4 hour Endurance race is amazing,they're so fast at night!!






So we made it to Spa and had a great weekend on the track.
Despite the fact that there are fueling issues, I was pleased with the performance of the Brick. It didn't miss a beat all weekend and I lost count of people asking questions about the bike,lots of Photo's too! It handled well and when the fueling is sorted,it will make a great track bike. The only bikes that completely outclassed us were some of the guys on Superbikes No answer for hot motors with trick chassis' I'm afraid.
I met some nice people and made some useful contacts-what an event!

Next? 1200 TB's,a set of light weight wheels and more engine work.

Watch this space.

The weekend after Spa saw us go to Cadwell Park in Lincolnshire.
The Sunday was great,weather good and the tracktime was fabulous. A big thanks to Classic Bike Trackdays for organising that.
I won a prize for the Brick!


It was quite emotional as I only ever build bikes to please myself. The fact that someone had decided to give me a very nice Granite plinth was very,very nice. Thanks to practical Sportsbike magazine too,the T shirt fits a treat.



On the Monday it was the BMW owners club Ride Friendly day which again was very emotional......but for the wrong reasons!!




Whilst approaching a slower rider around the outside,he made a sudden lunge for the edge of the track. FK why. I was left with no where to go but the grass. I thought I could save it but a large bump came up and catapulted me out of the seat into the stratosphere. 
The bike isn't too bad,nothing major,just minor damage but it's everywhere.










I'll kick it straight for now and rebuild it over the winter.
Fortunately,I bounced better than expected but did get a (several if I'm honest!) roasting from the Mrs-as if I needed anymore trouble right now!

The high's and low's of biking eh lads?

See the camera on the fairing, Mike. Any footage for us to see?

Comberjohn wrote:See the camera on the fairing, Mike. Any footage for us to see?

Hi John,
I didn't have the camera on the bike when I crashed but have some footage from Spa and Cadwell.
I suppose I'll have to upload to Youtube but having not done it before,it may take some time!

Find a ten year old to show you how to do it. 

Comberjohn wrote:Find a ten year old to show you how to do it. 

I eventually found a 10 year old who was prepared to help me out!

I couldn't resist starting another tank.
I wanted one narrower at the back to give more room to climb around the bike.
As you can see,it's quite a bit narrower than a stock tank.

So, you decided to use the tig welder instead of the mallet This time😀


K-rider

Both.
More mallet to come if I decide the front sides need some tough love. 

Hi Guys,
I've just come across some images of the bike in action.
The pics with the yellow helmet were taken at Spa,black helmet at Cadwell Park.
I hope you like them!

Nice!

Kool, I just watched the video. Very Kool, almost fell out of my chair leaning over with you around the corners.

Waz wrote:Kool, I just watched the video. Very Kool, almost fell out of my chair leaning over with you around the corners.

+1 Waz...... Never got the knee down at the kitchen table before 

Aside from the sheer weight having it's own effect, the bricks handle quite well when you "tighten" the chassis up.
What are you all waiting for?

Well... I've got scrape marks under my boots but never had the pegs down. Does that count?

Knee's and belly pan but never the footrests so that's two of us.

Belly pan, really? I never tried that. But footrest on both sides. Are scrapping the tarmac from time to time

K-rider

My footrests are along the same line as the swing arm pivot and the bike is raised 30mm at the rear.
I have had the right footrest touch down though,when I crashed it!! 

I thought it was about time I started to pull the Flying Brick apart because it needs some love.
I've ordered new bodywork to replace the damaged fairing, I've started a new tank which will be much narrower at the rear and there's a new engine in bits as I type getting vapour blasted because it's scruffy.
The new engine started life as a K1100LT but we have RS cams, the internals will be lightened as much as possible, 1200 throttle bodies and the head will be skimmed for more compression as piston options are not available. There's lots of piston to valve clearance with the RS cams so no issues there.

There's nothing wrong with the old 8 valve unit, it's a huge spec but I want more power and can't find a 1200 engine for sensible money so 1100 16v it is.

Motorbike Mike wrote:The new engine started life as a K1100LT but we have RS cams,

The K1100LT and the K1100RS have identical camshafts.
Maybe you mixing with the K12, where they differs between the RS/LT.

Same subject but off track a bit. I was groping about on RealOEM a few weeks ago and it seems that the Australian market had different cams for the K1100 LT and RS than Europe. I didn't check out US bikes.
Inge you are probably better at the interpretation of the parts catalogue what are your thoughts on this.
I think the cams probably are different as I got a set of K1200RS ams from US some time ago and put them into my K1100 and the difference was remarkable. So remarkable I took them out as I didn't like a touring bike standing up at 5000rpm in 2nd gear.

No surprise as the K12RS (and LT) have different cams than the K11's

There may have been a few things changed within the ECU as I really dont think that the power should come on that hard and I certainly didn't expect it.
First time my K1100 lifted the front was in 3rd when I was overtaking  and was fairly gentle and I was loaded to the rear quite a bit but then a few times I guned it in 2nd and it stood vertical so not wanting and exciting life at my age I removed them.

Inge K. wrote:

Motorbike Mike wrote:The new engine started life as a K1100LT but we have RS cams,

The K1100LT and the K1100RS have identical camshafts.
Maybe you mixing with the K12, where they differs between the RS/LT.

Inge,
Well spotted and you're absolutely correct. I have K1200RS cams that are a 284 cam-sorry, I omitted the 1200 from my description.

If the 284 cam hits that hard, that will suit my bike just fine. 
If any of you guys have a set of 12RS cams going spare, let me know. I might slip a pair in my K11LT too.

What a beautiful custom project Mike!  Luv the track pics!!  Keep up the outstanding work...
Best,
OG

Hi OG,
I'm still waiting for my K11 engine with K12 cams, skimmed head to raise compression, lightened internals with lightened and balanced crank.



This is what I have at the moment
so there's plenty to get stuck in to.

Mike.

I have to admit I became distracted by another thread I started so back to it.
I have my K1100 16v engine back with K1200 cams, skimmed head, lightened and balanced crank, slightly reshaped ports, K1200 headers, K1200 oil/water pump to facilitate an oil cooler for better cooling.

I'd only had the motor back a week when I had to be stripped again to fit a K1200RS output shaft to run the new pump assembly.
Here's an easy way to fit the gearbox and drive onto an upturned engine.

Once fitted, I laid everything down and dropped the frame on top and bolted it all up.


Last year I used an 8 valve motor and injection but the 16v injection system is slightly different as the injectors fit into the throttle body inlet stubs, I presume most of you knew that. The 16 valve fuel rail has the pressurised flow  pipe in a different position and has the flow pipe pointing outwards and down. I had to move the pipe to the opposite side so the fuel pipe sat inside the fairing and weld up the disused inlet-nothing's simple. 






Radiator fitted with a fresh coat of wrinkle finish black hi-temp paint. The curved silicone pipe on top of the motor doesn't belong there before I'm asked what it does.

The part that caused all the pain has finally been fitted

Looks like a bought one, when do you put it to the test? Be interesting to see how the temp goes in the heat of battle. Are you fitting the oil cooler as well or doing a compare before and after style?

Motorbike Mike wrote:The part that caused all the pain has finally been fitted

Yes, it looks very professional.

As a reminder, just a tip to avoid your bike/engine tipping on the lift...

Read post #20 here

  That is a great idea bolting the support bars to the side of the motor but unfortunately I have 2 broken bolts in the left side. 
I've got too many jobs to get done to invest any time removing them-one day.

This is how a redneck gits 'er dun:

When yer all done and the engine is back in the frame you can chop up yer lift, throw it in the stove and use it to cook breakfast.

No, the wood will have to go on the bed frame. I stole 2 supports to hold the bike up-from the Wife's side obviously.

K75cster wrote:Looks like a bought one, when do you put it to the test? Be interesting to see how the temp goes in the heat of battle. Are you fitting the oil cooler as well or doing a compare before and after style?

I tried it without an oil cooler last year and it struggled, on the slowdown lap it would boil over.

This past 4 days has been spent making an air box to get fresh air to the engine.
I decided as a start I'd use stock K1100 rubber connectors and velocity stacks. The stock rubbers etc wouldn't fit inside the fairing but it was #1 stack being near the to front down tube that threw the other 3 out.


 I made an alloy air box (MK1 version) to start with. It's not huge but I can increase volume on the bottom or start again if need be. 







I doubt that Ron Dennis at McLaren will be worried about my intake development program!!

I've also finally got the oil cooler fitted up. It's rubber mounted as the vibes will tear it apart if not.
It never fails to amaze me how much time it takes to make one off parts. If you want something right it's hours of fit, file, fit, file, drill-you know don't you?

Hello Mike!

I'm curious to hear how the bike will run!!!
Well done, looks like a good track bike.

Cheers

Too right, Mike, and my project's just a pile of oem parts bolted together. Hardly a collection of one-offs like this.

I'm still not sure where to place, and of what version, my oil cooler will be. I've a triangular Ducati type, an automotive transmission version, and a larger motorbike type. It's all down to how to mount it as much as where.

I'm enjoying your build notes and look forward to more wheelie pics from your favourite tracks.

wow! love it! looks awesome keep the pictures coming

Although I've only got last years 8v 1000 to compare with, I'm at least hoping for a more responsive bike.