New User - BMW k100 Microsquirt set Up?

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davidb5823
MS/Extra Newbie
Posts: 4
Joined: Wed Nov 09, 2016 1:39 pm

New User - BMW k100 Microsquirt set Up?

Post by davidb5823 »

Hi Everyone,
I am new to the Forum and am looking for some help and advice prior to purchasing a Microsquirt system.
I am building a café racer style motorcycle based on a BMW K100 – 4 cylinder in-line 1000cc water-cooled with K1100 throttle bodies (slightly larger than K100’s but more importantly, has a “proper” TPS) and has high-impedance fuel injectors (measured at 16 ohms). It has no cam sensor but has two Hall sensors on the crankshaft. I want to have the stripped-out café-racer look so intend to fit coil-on plug
My initial questions are:
1. I assume that Microsquirt is the best option for size and functionality for a motorcycle?
2. As there is no cam sensor, will the system work with just the crankshaft hall sensor(s)?
3. For coil-on-plug, I obviously need to find COP’s which fit inside the physical space available, but do I need to select COP’s with certain dwell settings? I am still reading-up on this so please excuse my lack of knowledge.
Thanks for any help - it is appreciated.
Dave
Matt Cramer
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Re: New User - BMW k100 Microsquirt set Up?

Post by Matt Cramer »

MicroSquirt can run this engine in wasted spark using something like a 60-2 crank trigger. What sort of RPM does this rev to?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
davidb5823
MS/Extra Newbie
Posts: 4
Joined: Wed Nov 09, 2016 1:39 pm

Re: New User - BMW k100 Microsquirt set Up?

Post by davidb5823 »

The standard engine produces around 90 bhp at 8000-8500 rpm - so I imagine the red-line is around 9000-9500 rpm.
I will check the manual for max revs.
Thanks.
R100RT
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Posts: 1038
Joined: Thu Jun 30, 2011 12:45 pm
Location: British Columbia

Re: New User - BMW k100 Microsquirt set Up?

Post by R100RT »

Matt has basically answered your ignition trigger question with mention of a good chopper wheel choice (I'd tend towards the little 36/1 wheel). There most likely will be trade offs and poor performance trying to utilize the stock dual Hall "Bean Can" unique to the BMW's, low resolution. However, adding a trigger wheel will have some challenges.I have an upcoming project on a K75 where I plan to plumb the depths of its abilities ( stock bean can) and wish to log stock Motronic ECU performance and settings on a running bike prior to doing another sequential ignition set up (really, the best way to go)
The other questions, MicroSquirt is a good choice for its compact size and abilities. I have some earlier V2 releases that have plenty of options and works well with Extra code.
Coil choices are vast, it will boil down to what you wish to spend and is available in your area.
Good luck, lots of fun ahead.
1983 BMW R100RT Motorbike
Turbocharged - Water/Meth
Sequential Ignition & Fuel
"Perky Sleeper" that excites bike enthusiasts once discovered (or being passed)
Newest project - 1995 BMW K75 is V3 Microsquirt, "Turbocharger - Of Course"
davidb5823
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Posts: 4
Joined: Wed Nov 09, 2016 1:39 pm

Re: New User - BMW k100 Microsquirt set Up?

Post by davidb5823 »

Guys, Thanks for your replies. The best way forward is probably to buy the Microsquirt system, get everything wired-up, then get back on the forum if (when) I need some help. Fitting a trigger wheel in the space available (inside the front engine cover) would be challenging at best, but is probably an avenue to explore. A cam sensor would be great - would a sensor pick up a reliable signal if the back end of the camshaft had notches machined into the "spare" metal at its end? Just a thought but may be possible as I know a capable local engineer....
R100RT
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Posts: 1038
Joined: Thu Jun 30, 2011 12:45 pm
Location: British Columbia

Re: New User - BMW k100 Microsquirt set Up?

Post by R100RT »

I am no where near pulling my K75 down yet, but I believe the simple approach will be to remove the stock timing plate from the crank adaptor up front, and hall sensors, and machine that or a new wheel for a reasonable tooth form (not so much a bean can as a "bean zone" :lol: ). I'd be recommending a VR sensor as they are so common and have excellent heat resistance, and the rule seems to be a smaller tooth dimension than the probe tip (but definitely not the other way around). A 36-1 wheel might then be possible but I'm not sure of the diameter on that little disc. However, that zone on our K bikes is wide open and would be very friendly towards a slight modification to the cover, to gain more room - move forward a tad, etc. You could do wasted spark and gain very good operation and simplify coils etc. I suspect placing your main pick up on the cam might reflect chain and tensioner slop/ play but that is just a theory at this point.
To go further and create sequential ignition (my definite plan), a single tooth could then be set up on a cam gear and your Microsquirt will have conditioning to allow a VR to work on that at slow speeds nicely as well (my V2 version did not, but I added a little conditioning chip by Jean B on forums, after I found cam sync took too much rpm). I know my overall sync doesn't occur quite as low as I can measure rpm's, but I have documented as low as 19rpm when testing components on a drill press with all belts off, and spinning by hand. As another recommendation, I would test everything off bike, including a little "Jim Stim" which is an affordable device more intended for those building their boards to confirm suitable function but which works really well on built units to ensure you'll turn your key and fire up first time.
1983 BMW R100RT Motorbike
Turbocharged - Water/Meth
Sequential Ignition & Fuel
"Perky Sleeper" that excites bike enthusiasts once discovered (or being passed)
Newest project - 1995 BMW K75 is V3 Microsquirt, "Turbocharger - Of Course"
davidb5823
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Posts: 4
Joined: Wed Nov 09, 2016 1:39 pm

Re: New User - BMW k100 Microsquirt set Up?

Post by davidb5823 »

Thanks again for all replies.
I am also looking at the coils (on plug) and am trying a few for "fit", before committing to purchase a set. Is there a shorter COP available? I have tried a couple but they are rather long and protrude out past the cam cover. Probably not a major issue on a car engine but looks rather unsightly on a bike where all is on show.
When I work out how to post an image, I will include a couple of photo's to show what I am trying to achieve. I am new to forums and have not yet mastered this vital action!
R100RT
Super MS/Extra'er
Posts: 1038
Joined: Thu Jun 30, 2011 12:45 pm
Location: British Columbia

Re: New User - BMW k100 Microsquirt set Up?

Post by R100RT »

I chose some small Nissan COP units for my airhead, twin plugged so 4 in total on the boxer engine. The direction I went was to mount the coils slightly away from the cylinders and configured some high tension leads to bridge between the two. Granted - slightly unorthodox, but that has worked very well and I was able to score good used parts from auto wreckers to test things rather than commit to high $$. Worked so well that I have just left them on, have a few spares to boot. (no pun intended)
For photos, while posting take a look at the bottom where it states "Upload Attachment". The rest is very simple.
1983 BMW R100RT Motorbike
Turbocharged - Water/Meth
Sequential Ignition & Fuel
"Perky Sleeper" that excites bike enthusiasts once discovered (or being passed)
Newest project - 1995 BMW K75 is V3 Microsquirt, "Turbocharger - Of Course"
crimona
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Posts: 2
Joined: Sun May 23, 2021 7:42 am

Re: New User - BMW k100 Microsquirt set Up?

Post by crimona »

Hi guys. Have you find a stable recipe to K bikes?
I am new in K bikes and megasquirt also. I only managed to master Trionic till now.
Now I started my k100 project and I intend to put a wolf into a sheep fur. Something usual: modern brakes, suspension, slightly improved engine internals, ignition and fuel injection at lower cost in money and weight. Maybe for 20BHP/Nm or 1,5kg in weight saving is not worth upgrading but at list I hope that low ECU volume and filter box ectomy space saving to convince me.
R100RT
Super MS/Extra'er
Posts: 1038
Joined: Thu Jun 30, 2011 12:45 pm
Location: British Columbia

Re: New User - BMW k100 Microsquirt set Up?

Post by R100RT »

Hello Crimona,
Interesting project that you describe.
Although I am building a K75 with MicroSquirt, it is not yet finished.
I can offer some advice, for MS to recognize and sync to the crankshaft position etc, a modified tone wheel is required. The stock Hall effect sensor and rotor with window will not support ignition (it will support fuel).
Popular methods include fairly small missing tooth tone wheels or multiple window rotor. If your engine uses a Mass Air Flow sensor within the large intake chamber, you either need to keep the chamber and sensor, or go with map sensor. Your best way to succeed with least challenge is to determine type of MS ecu and system you want to use, and then thoroughly read the manual for that (located at beginning of each forum section).
Good luck on project,
Lorne
1983 BMW R100RT Motorbike
Turbocharged - Water/Meth
Sequential Ignition & Fuel
"Perky Sleeper" that excites bike enthusiasts once discovered (or being passed)
Newest project - 1995 BMW K75 is V3 Microsquirt, "Turbocharger - Of Course"
crimona
MS/Extra Newbie
Posts: 2
Joined: Sun May 23, 2021 7:42 am

Re: New User - BMW k100 Microsquirt set Up?

Post by crimona »

Thanks Lorne, I'll look into it. In the way I see it looks for me as a new fresh development since there is no fixed receipe. Trials and errors will make it time consuming. Maybe I'll divide my project in two parts leaving engine electronics mods for the next winter. It is time consuming and I want to ride it this summer.
R100RT
Super MS/Extra'er
Posts: 1038
Joined: Thu Jun 30, 2011 12:45 pm
Location: British Columbia

Re: New User - BMW k100 Microsquirt set Up?

Post by R100RT »

Faced with a decision to ride, or park bike and develop a new system, you are wise to hold off. These kind of projects are great "off season" jobs where you can slow the pace to learn new things and plan a strategy nicely, rather than bodging to get back on the road asap.
The good news is that gaining better than stock reliability, adjustability, and performance is pretty well academic, when treated to careful and deliberate, manual based procedures.
1983 BMW R100RT Motorbike
Turbocharged - Water/Meth
Sequential Ignition & Fuel
"Perky Sleeper" that excites bike enthusiasts once discovered (or being passed)
Newest project - 1995 BMW K75 is V3 Microsquirt, "Turbocharger - Of Course"
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