Carbs and stuff.....

[(RIP) trickytree]

Been thinking about this for a while and spurred on by this comment in another thread...

.....But when the ECUs pack up the bike will probably be scrap.....

....I thought I would throw it out there.
I'm not interested in hearing from the 'why would you want to' brigade or start a slanging match on the whys and where fors. It's not that it's something I'm particularly contemplating but it's for tight arses like me that are never going to have the 'luxury' to be able to afford to take increasingly complicated bikes to a main dealer....I do all my own spannering and want to continue to do so.

So, Oil Heads can be run on carbs, Pazon make a ignition system so it's pretty straight forward. So, purely from a technical point of view could it be done to a Hexhead?
Don't think ignition would be a huge problem, it's only a 180 degree twin after all. Not sure about compression ratio....think it's up around the 12-1 range so pre ignition will need monitoring.
Another option would be an aftermarket injection control system....I was thinking Megasquirt but there's also Microsquirt which is a simpler system.
Either going carb or aftermarket injection would enable you to get rid of the canbus and replace it with wiring that can be repaired just about anywhere....think I'm right in assuming that getting rid of canbus means getting rid of the stock ecu?
Anybody done it or know of something similar?

 

[sherpatensing]

Interesting but...If you're concerned about canbus and fuel injection, go and buy an R75 or R90 or indeed choose something from the huge range of 70's and 80's bikes. They will feel like a bag of shite compared to a modern bike but still great in their own way.

 

[Deleted account 190920001]

1 These systems although not bomb proof are very reliable, even on a BMW.

2 As above if it bothers you buy an older/different bike without all the tech.

3 Getting rid of "CANbus" is a complete throw everything electrical away and start again including the clocks and switchgear. The whole electrical system is based on several computers all working together. Loosing one part will stop the rest from working.

4 If you rewired it all and changed out all the parts needed I would still go with an aftermarket ecu like megasquirt. Modern engines need it to produce the power. I am pretty confident that going carb you would loose a good bit of power and driveability.

Ultimately it just wouldn't be the same bike but yes I guess it could be done. It would have to be a keeper as nobody would buy it for any reasonable amount of money.

 

[UturnTony]

All good and interesting stuff but, isn't it true that by the time you have done all that, wouldn't it be cheaper and easier to replace new/used/get repaired the faulty item?

Just saying like

 

[MattW]

The ECU runs much more than the fuel injection / ignition.

It was a goer on 1100’s which were much simpler (no canbus) but on 1200’s you might as well replace the defective part. It would probably be much simpler and cheaper in the long run.

 

[Mistacat]

The can bus is one of the best parts.
Take half an hour and study the BMW wiring diagrams and it will become obvious how simple fault finding is.
Compared to some, especially Japanese looms with crimped connections inside the loom and blocking diodes hidden every ware.
With the reliability of the ECU`s and the capability of the GS911 ( I would not leave home without it), Is what makes these bikes such a brilliant touring machine that can so easily be looked after without going anywhere near a main dealer.
I can understand fitting points & coils and a pair of Bing carbs and dropping the compression ratio, ( all easily done) if off to ride in the real wild.
But to alter an intelligent management system which is very reliable ( second hand ECU`s would not be so cheap if they were not reliable) I do not understand.
Whilst the Megasquirt , Microsquirt, Emerald etc Diy systems all have their place, along with crude Japanese and american fuel management systems they don`t compare to the BMW system.
There are a few changes to the BMW system I would like. Ie. Throttle position sensors on both inlets. having the idle actuators separated and controlled by MAP sensors etc.
But all in all my 1200 is a reliable easily worked on bike and with the help of modern electronics in the form of the AF-XIED`s very easy so set the fueling to suit my needs.
Probably why I do 14K miles a year on the R1200 and 1k miles a year on my R100.

 

[Bendy toy]

My issue is not the technical design but the physical delivery. Canbus is supposed to be simple but the sheer number is wires hardly supports that.
Looking at the ECU connectors I can see all sorts of future problems mostly down to packaging and corrosion.

The bike would benefit greatly from a connector by the battery to remove the back end of the loom. Four frame bolts, suspension strut and exhaust are all it takes to remove the back subframe. But the tits at the factory made the airbox part of the subframe and routed cables clutch hose etc in perfect ways to make everything difficult.
Change the alternator and you will spend more time farting about with wiring loom than almost anything else. This puts strain on the connectors and terminals within.
With a little thought and team work the bike could have been built lighter and less complicated to assemble. Result - more profit or sold for a lower price.
It's always easy to criticise and find fault but BMW really did miss some golden opportunities when they designed or more likely evolved the Hexhead.

 

[Mistacat]

Looking at the wiring diagram there are the minimum number of wires that can be used to run the systems provided.
Without Can bus there would be a lot more wiring, relays, fuses, and blocking diodes.
I would agree a plug mid frame would make life easier when removing the rear subframe.
Not sure why you say the airbox is part of the rear subframe?
I know you have to remove the the subframe to remove the airbox but the airbox is not a part that is going to need changing.
Working on BMW Boxers is a doddle compared to a lot of the bikes out there.