BMW K100rs 1985 MAF/AFM bypass

12757 Views 16 Replies 9 Participants Last post by TrialsRider, 19 d ago

daniel.binedell

Discussion Starter · Mar 25, 2017

(Newbie alert) Is it possible to by pass the AFM and/MAF sensors if I install a Megasquirt system?
Would like to get rid of my airflow box and put on air cones.

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gs1327

· #2 · Mar 25, 2017

Yes, you can use a MAP and TPS with the megasquirt- but if you are asking this question you may want to reconsider. Megasquirt is not exactly a bolt on modification. One of 2 things will happen- you will learn a TON about EFI and spend the next few months wiring and studying, or the bike will never run again. I'm in the middle of my 2nd EFI conversion and it's making my head spin. But I'm pretty old and feeble- minded. If you go this route be sure to document the process here, I'd be interested in seeing the process.

Part of of the problem is there is no "factory" tech help or support for Megasquirt- it's all forum based support, which means you either figure out your problems on your own, or wade through ten useless answers trying to find the correct response. There are a lot of really sharp people there, but there are also a lot of people that just like to reply to forum posts. Just like you find on any forum.

brad black

· #3 · Mar 25, 2017

i don't recall if the hall sensor is the same part for 2v and 4v, but all the 4v stuff - throttle bodies, ecu, wiring, coils - should just go on i would think, as it's somewhat the same bike**, and that way you get an n/alpha system. i think that'd be easier than going to an aftermarket ecu. you could just use the fuel side of it too, as the 2v has it's own electronic ignition.

** of course, that part might be total crap.

daniel.binedell

Discussion Starter · #4 · Mar 25, 2017

gs1327 said:
Yes, you can use a MAP and TPS with the megasquirt- but if you are asking this question you may want to reconsider. Megasquirt is not exactly a bolt on modification. One of 2 things will happen- you will learn a TON about EFI and spend the next few months wiring and studying, or the bike will never run again. I'm in the middle of my 2nd EFI conversion and it's making my head spin. But I'm pretty old and feeble- minded. If you go this route be sure to document the process here, I'd be interested in seeing the process.

Part of of the problem is there is no "factory" tech help or support for Megasquirt- it's all forum based support, which means you either figure out your problems on your own, or wade through ten useless answers trying to find the correct response. There are a lot of really sharp people there, but there are also a lot of people that just like to reply to forum posts. Just like you find on any forum.

What about the Megasquirt-3 with MS3X? Seems quite straight forward unless I am missing something..

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brad black

· #5 · Mar 25, 2017

what you're missing is a list of as many bikes as you can find successfully running some sort of "grass roots" aftermarket ecu. aside from something like the cliff jeffries myxx ones, it generally seems that the projects start and never go anywhere. using factory bits always seems to go better, or buy something that bolt on and will work guaranteed. if it exists for the 2v motors.

injection stuff is really easy. unless you want to design an ecu from the get go. then all the underlying stuff that the big companies worked out years ago that you'll never know you don't know bites you. freewheeling starter clutches like a lot of bikes use can be very upset by start and stop routines - no idea why, but it's something that weber had to change on the early ducati 851 eproms to help starter clutch life.

jcw

· #6 · Mar 25, 2017

daniel.binedell said:
(Newbie alert) Is it possible to by pass the AFM and/MAF sensors if I install a Megasquirt system?
Would like to get rid of my airflow box and put on air cones.

Sent from my SM-G935F using Tapatalk

Nice looking bike!

Interesting project but is it really worth it?
It's like tearing down and rebuilding a house because you don't like the paint color in one room.

Here's a guy that took it as far as he could. Then sold it.
The motobrick site looks down but here's google's cache of it.
Sold: Megasquirt for a K75- BMW K75 K100 K1 K1100

Re: Sold: Megasquirt for a K75
« Reply #7 on: July 15, 2015, 08:10:49 PM »
There should be enough documentation on this and the MSextra forums to get most of the way there, especially if using a cased microsquirt (which I would suggest, unless you really want to play with/ customize stuff. hindsight 20-20).

I attached the files I have, which includes base tunes, renders/models of the planned hall wheel ignition setup, the breakout board, among other things.

https://drive.google.com/file/d/0B29HQe4CE8wgWUVERHJKeHktcUU/view?usp=sharing
Logged

Ann Arbor, MI
1991 BMW K75 Standard, Refreshed '94 engine

Bikes:
Current:
1991 BMW K75 Standard, Refreshed '94 engine

Past:
'83 BMW R65LS (An R65 with a prototype K Bike Front End)
'75 Honda CB550F
'69 CB175
1999 Royal Enfield Bullet 500 (Last month of the original '55 model)
1973 Triumph Tiger TR7V (5 speed, Right Shift, Disc Brake)
1971 BMW R75/5 in Toaster outfit
1979 Harley Davidson XLS-1000 Sportster Roadster

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gs1327

· #7 · Mar 26, 2017

There seems to be a lot more megasquirt projects "in process" than finished projects. It's an easy project, unless you want to finish it- that takes a little more tenacity.

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hillsy

· #8 · Mar 26, 2017

There was a guy on here a while ago that put a set of R1 carbs on a brick - I imagine that would be less frustrating than trying to build an EFI from scratch.

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Geeto67

· #9 · Mar 26, 2017

That's a lot of work just for individual filters that won't improve performance. You'd almost be better of saying "I want to convert a k bike to carbs" and then making your own manifold and spending hours dyno tuning the thing than figuring out how to use a megasquirt. If you spend the money and go wit Weber DCOE carbs then it really looks impressive but now you are into the intake system for thousands of dollars.

Have you you looked into converting your jetronic to motronic of an 1100?

This still seems like a waste of effort, the plenum draws cold air from the front of the bike, individual filters would just be buried deep in the engine and suck hot air in.

This is one of those time where you should ask yourself: am I smarter than a BMW engineer? Because what you are trying to do requires an engineering solution to keep all the horses in you bikes engine.

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daniel.binedell

Discussion Starter · #10 · Mar 26, 2017

Thank you all for the great input! I have decided to leave this alone and keep it stock.

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TrialsRider

· #11 · Mar 27, 2017

Wise move; the motor in it's stock form and maintained well is bulletproof and performs well, fuel injection system is practically maintenance free. Brakes and suspension are a little weak as a result of early technology limitations. It's a bitch to find really good rubber for these bikes using the stock rim sizes, but considering the bike really is a high speed Sport touring motorcycle and Not a track bike, that's not a disaster.
I think you are stupid to ride it fenderless and without the full fairing that was wind tunnel tested to give that bike Stellar high speed performance. The RS mirrors are the absolute best that have ever been put on a motorcycle because they make your hands part of the streamlining, you've discarded All of the fantastic storage areas, but hey, you're the one that has to ride it.

Pass you later.

TrialsRider

· #12 · Mar 27, 2017

Just incase you need a reminder what the K100RS is suppose to look like:

<-

my k bike

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daniel.binedell

Discussion Starter · #13 · Mar 27, 2017

TrialsRider said:
Just incase you need a reminder what the K100RS is suppose to look like:

<- my k bike

Great looking bike ?

I just don't like my bikes looking stock, I want something that I created that no one else has.. if that makes sense

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Geeto67

· #14 · Mar 27, 2017

since this conversation seems to keep going....I will say that one place where a megasquirt would make sense is if you wanted to turbocharge your engine. Forced induction over say 6-8psi is generally going to be outside the design parameters of the stock injection system.

So if you went turbo you would change the intake, exhaust, throttle body and fuel system. This would allow you to run one large cone filter off the turbo intake, and also reduce the intake system to one large throttle body. A megasquirt operating a simple FI system like that with a TPS would be ideal. then you could crank the boost up to 14psi+ (provided you had the right engine internals like lower compression turbo pistons).

There were K100 turbo bikes back in the day sold by luftmeister and designed by RB racing:
https://www.rbracing-rsr.com/bmwturbos.htm
https://www.rbracing-rsr.com/bmwK1000.html

the "Race kit" with their own ignition controller, appropriate engine internals, RB's own FI system, and blowing 15psi was good for something like 180hp on race fuel. Even their street kits with the higher end components supposedly could touch 125hp set to kill - so if this is a rabbit-hole you want to fall down there is room to get crazy power out of a flying brick. This would be a great use for a megasquirt because it could be both an FI controller and ignition controller, replacing the systems RB was developing back in the 1980's-90's.

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volymard

· #15 · 19 d ago

God, I hate the sight of the POS. Stupid, ugly, electronically over-engineered useless flaming kraut lump, it's gutless crap and bmw are fucking rip-off artists and the price the aftermarket wonks charge for their cheap chinese shit, I wouldn't buy their crap just on principle. Fucking trendoids with your shitty café racers parked on the pavement on weekends, just laughable. Get a REAL BIKE. Another few years, with no more parts, these things will be as dead as dogshit and good riddance.

Reactions: 1

woodsman

· #16 · 19 d ago

volymard said:
God, I hate the sight of the POS. Stupid, ugly, electronically over-engineered useless flaming kraut lump, it's gutless crap and bmw are fucking rip-off artists and the price the aftermarket wonks charge for their cheap chinese shit, I wouldn't buy their crap just on principle. Fucking trendoids with your shitty café racers parked on the pavement on weekends, just laughable. Get a REAL BIKE. Another few years, with no more parts, these things will be as dead as dogshit and good riddance.

And here we are all waiting with bated breath to read your opinion on a 6 year old thread. Good of you to finally drop by an spew some bile. It is the type of brilliant insight that you bring that we were missing.
And you're so on topic. The way you explained an FI conversion with your outstanding prose, well you are obviously a genius.

TrialsRider

· #17 · 19 d ago

He thinks a K bike is gutless and electronically over-engineered

volymard show us the POS you ride.

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