Welding, CANBUS, Zen, and the rapidly fading love for BMWs.

So....

I fitted a Touratech 20 litre tank. The crashbars obviously didn't fit, so I cut them up and prepped for welding.

I disconnected the battery, positive and negative terminals. I bolted the crashbar pieces onto their respective mounting points and tacked everything up. Earthed as close to the welds as possible.

Removed and welded everything up at the workbench.

Everything worked just fine. Superb result.

Rode the bike to the servo and filled the tank, perfect.

2 days of riding later I use the brakes and the ABS is intermittently intervening for no discernible reason.

This continues for a couple of days.

Then the ABS fails completely as I'm approaching an oil covered roundabout in the pissing rain with a Kenda Big Block tyre on the rear. It caught me by surprise because I was taking it easy, having already established that the Kenda was the worst tyre I've ever used in the wet.

Hilarity ensues.

As I try to control the sideways BMW, a car slides through from my right (we drive on the wrong side here - the left) and while I'm still trying to bring shit under control he is rapidly looking like hitting me. Turns out it's a she, and has hit the oily roundabout at full knots, rain be fucked. Barely misses me, and goes sideways off the road, up a grass embankment, and misses me narrowly the second time while I'm again trying desperately to control the sideways BMW that wont stop, or turn, or do anything else without the wheels swapping positions, and the car ends up in front of me facing me. I ride around it and keep going. I don't trust myself to be calm and reasonable.

So I take it to the BMW shop and nearly die again on another oil covered roundabout...and they run diagnostics. Appears to be a cable fault. Then heals itself, then the ABS module completely fails. Software upgrade, it works, no it doesn't, now it's fucked.

They say it's due to the welding.

They say with the CANBUS, sometimes it "just happens".

Now the question is, will the 2010 ABS pump I bought off eBay from an F800RS work with my software or will the CPU say "file not found"?

I'm fitting it this week and visiting the friendly ever helpful BMW shop if the software doesn't recognise the new one, and they can run diagnostics and confirm. Regardless of the outcome, I am not paying the $2400 they are asking for a new ABS pump unit (they don't sell the electronics separate to the entire unit).

If things don't go to plan, it's getting parted out. I've been leaving it parked outside. Just my luck the stolen vehicles stats are down.

I really don't see how a few tack welds on crash bars would hurt an ABS pump, especially with the battery disconnected.

I could be wrong though. Wonky things seem to go on with these things.. I just talked to a friend yesterday that had $700 worth of brake drama with his '05 1150 GS. Frozen calipers, break lines bursting, inability to bleed the system.... Ugh

The ABS brain in my '07 BMW recently died in similar fashion after use of one of those battery chargers designed to also start a vehicle.

Hey, I fucked up when I thought I had taken proper steps to prevent damage. You did too.

Modern vehicles including BMW motorcycles do not handle surges like these without expensive consequences. If you find a brand that is immune, please share!

Fred

It is what it is. I can't change it now.

It is disappointing. Not in a devastating "I hate BMW forever" way, but nonetheless, disappointing.

On the up side, my DR650 has had about half the frame removed, rewelded, and shunted back together without disconnecting anything.

I have been warned by friends that when they've fitted electronics from different models to their BMWs the CANBUS has refused to recognise the other models parts, even though they plug straight in and do the same job.

The dealership can't tell me, naturally they recommend buying a brand new one.

I got a complete pump assembly for $250 off a different model because I couldn't find a GS one. I figured worst case I'd relist it and sell it.

edit: this is incidentally also the reason I have hesitated replacing the clutch that has run out of adjustment, and the reason I'm no longer looking keenly at a Rekluse. Until I get past this ABS module sticking point I'm on the verge of disposal for whatever I can get for it.

If everything works I'll replace the clutch and keep going. Maybe someday a Rekluse. But for the moment I feel that spending the absolute minimum on it is the best course of action. There's not a chance in hell I'll sink $2400 into it. If it takes that, it's gone.

OK Snowy:

What's an F800RS?

ABS pumps are VERY specific. The module you bought should say "K72 800" stamped on it on the top shiny aluminum part. K72 is the 800 Twin designation and 800 is the model. A K72 650 is incorrect for example as they have one front disc. When researching my 800 I found that the pn's are different for most models.

Try this:

Disconnect battery and unplug ABS.
Cut cable ties then pull the plug as far out of the frame as you can.
Connect new ABS and reconnect battery.

See what happens when you turn the key on. If the ABS light stays on solid then it's not happy. Don't know if programming will help. If things go well then install it, bleed etc.

For the record I added ABS to the 800 I put your forks on. Everything worked as planned except the red ABS light doesn't work due to programming. Dealers won't touch it as it would need to be reidentified with a factory CD. A new identity.

Good luck. You could always just disconnect the plug and carry on without it with a piece of tape over the red light..

I hate to say it, but i've seen other bikes and cars react badly to welding while the ECU is connected.

I've run into worse scenarios. To this day, if a welder comes close to my stuff, the ECU gets unplugged.

I work for BMW automotive tuning firm and our fabricators will remove all ECU's and ignition coils from a late model BMW car before welding on the chassis, Not just unplug but remove from the car.


They will spend hours removing complete front or rear suspension sub frames from the car to weld on the bench so not to damage the multitude of electronic control units in the car.

-Jeff

and then there are those of us who dont do any of the above and just weld on the bike and have no problems....i tigged mine,and dont recall having any issues with it at all after done ....didnt touch or unplug any electronics....must be a ghost in the machine

I work on import cars for a living and Bosch ABS unit failures are not unknown for several reasons. Might be jump starting with reversed cables or who knows what? There is a company we use that reliably repairs them. There are some models they can't do but the ones they do repair they give a 5 year warranty on.

Yes, there's a danger of damaging electronics when doing any kind of welding that requires a ground.

Many grounded circuits don't prevent voltage from going the wrong way...no diodes so to speak and can wreak havoc.

In the early days of car alarms, the easiest way to defeat them was to hit the bumper, or the chassis with a 50k volt stun gun. That would fry the electronics and you could open the door without setting off the alarm. All the power went back up the ground wire.

sorry, 2010 F800 ST, for some reason I keep getting RS ST and RT confused. I was looking at the different models a few days back.

On top it says it's a K71. Specifically EXA20U K29/K71

We'll see.

Currently I've just ridden it with the ABS light on and the ABS not working. It doesn't worry me. If it wasn't illegal, I'd just replumb the brake system without the ABS. It's far too much trouble, if it was optional I'd never buy a bike with it again. Which is not to say it doesn't work, just that it's too problematic.

Substituted ABS units and disconnected battery.

Red light still solid.

I'll change the unit in the morning, bleed the brakes, take it to BMW and run diagnostics. I have no faith in it working.

If that fails then I'm replumbing it short term. Then it goes on eBay in parts.

It's been an interesting experience, but one that I wont repeat. The BMW is going one way or the other and I'm buying a car to replace it.

I'll stick to the DR650 for bike riding. It just keeps on keeping on.

I had a lot of fun with the F800, but the technical issues, design problems, constant niggling little failures have ruined the experience. The fact that the ABS electronics is in the words of the local BMW store a "known problem" when it comes to failures, but is not available as a separate parts item is in my view unacceptable in a modern electronic dependant world. Having the ABS system as complete single item spare part that costs 15% of the value of a new bike is ludicrous.

The fact that my own government is advocating mandatory ABS on all new bikes means I wont be looking to buy one of any brand for the foreseeable future.

Can you post contact info?
That's a name I'd like for my records!

Ditto.

BBA in Massachusetts remanufactures electronic BMW moto parts, including ABS modules. I have bought climate control modules and an ABS unit for my Saabs from them, but never thought to check for motorcycles until this thread.

Snowy, you should give them a call.

Fred

Cheers Fred, I'll hunt them up in the morning.

If you get an "Incorrect Variant" fault code you're done. I'd be tempted to try reprogramming it while it dangled on the connector to save some work. At least your Dealer is willing to try. Ours won't mess with used parts.

I emailed BBA. Waiting on a reply.

I'm reluctant to pull this thing apart. I'll ring the BMW shop and see if we can plug it in loose and run a check.

I may be able to get a repairable write off for the same price as the dealer wants for the complete ABS unit. Last one I checked out was a 2011 and had only cosmetic damage, went for $2K.

It's an option.

All told it's rapidly looking like it'll take $2K to get it back on the road regardless of what option I take.

With a resale of $8K max....unfortunately I don't see the point.

Unfortunate way to end the ride.


To add to the misery, my right wrist has seized with carpal tunnel. No riding, so no work this week.

It is what it is. First world problems.

Patience

I had those fixed, too. Not by BBA, but by an orthopedic surgeon. Outpatient, done in a flash, staggered. (Don't have both wrists done at the same time, or you won't be able to wipe your own ass.)

Fred

Funny story:

My brother was out riding his mountain bike when he came across some elderly walkers on a steep downhill. They all stepped aside, but one of the oldest (about 80) stumbled in front of him and he nailed the brakes and endo'ed face first into the rocks. Broke both wrists requiring screws/plates etc. His new girlfriend holds the phone for him while he rings me after being pre med for surgery. He's telling me all about how is arm is perfect for going around the S-bend in toilets, and I ask him "So how are you going to wipe your ass?".

He goes dead silent for about 20 seconds and then he launches into a drug fueled "What sort of sick fucking prick thinks of something like that? What's fucking wrong with you?"

I've broken arms on many occasions. I know how this shit rolls.

The right wrist I broke twice while training for the Infantry version of the Olympics just after getting home from Somalia. First time I took 30 mins off training to have an x-ray and get it plastered. Snapped the head off the radius. I took my rifle so they could get my hand to fit the pistol grip. Returned, finished a demolitions lesson, then I did a 40 click pack march the next morning. Cut the cast off after doing a few weeks of training in the jungle, because it got manky after doing a 2 km tactical water crossing. Went on leave, bouncer in a night club twisted it up behind my back and it went "Snap". I finished my beer while being dragged to the door. Same break. A grand total of 11 weeks in a cast...on and off...got dropped from the team the night before competition started. G

Grunts. Some things will always be the way they've always been.

I'm still trying to wrap my head around this failure. I welded some racks on my F800, and didn't have issue. Like you I tacked in place, then welded on a table.

Can't tell if I just got lucky, or if maybe your abs failure just oddly coincided with your working on the bike.