DIYEFI.org Forum

Hello,
I have two goals that I would like to accomplish in this order
1...I am/was looking converting a 1970's motorcycle from points to a programmable digital ignition system. I was planning an rpm only based system for simplicity of
design and hardware. I am now considering incorporating a map sensor for sensing engine load. I think this would allow for a better tune.
This engine has 276.923077 degrees between spark events.

2...later I would like to install fuel injection. I have an Idea of the hardware I would like to use from a modern bike. its not direct bolt on but it will work with some slight
mods.

Almost forgot to mention I would like a small footprint for this project. I will be making two units one spark only and the other a full on ems. I would like to use a crank trigger only of course that would mean a kind of wasted spark setup I think but I might use a ckps and cmps set up alowing single fire and sequential injection when it is added.

Will this system work for me?
Are there better ways to accomplish my goals?
Where do I find the hardware, schematics, and pcb to assemble your product?
Is there an ignition only board available?

Thanks in advance for your input
Riksoto

Hello and welcome along!

1) I would strongly recommend installing a map sensor (or a set of them) and TPS of some sort so as to be able to tune the ignition properly. You'll get bad economy if you don't do this due to insufficiently advanced timing during light throttle operation such as cruising speed stuff. It will work OK, though. You don't really need the temperature sensors for ignition only control either, though you might like to tune advance for coolant and/or air temperature, or it might not matter to you, depending on your climatic range.

2) No problem when the time comes, hash out the details then.

Crank only trigger is fine, but your coils will be running at double duty, each fired at the correct angle, once on the exhaust stroke, once on the compression stroke. Worst case is warm coils. If they get too warm, they could die. A lot of people do this and I've never heard of it being an issue, even if it's not ideal.

If you tell me how many RPM the bike spins to, I can advise on a tooth configuration that is suitable.

Will the system work? Yes! But it's very much DIY, so you'll have to get stuck in and get your hands dirty. If you're not willing to put in the time, it won't work for you and you'll just get frustrated and hold bad feelings against the project. So if you're not the patient and hard working type, it could be best not to bother at this point in development.

There are other ways to accomplish your goals, better or not is subjective. MegaSquirt products might be easier, though many would argue not better, in some key ways. They are currently still better in other ways, though that shrinks every day as I achieve my goals.

If you want small footprint, you're on your own hardware wise. There are a number of hardware projects (FreeEMS is a firmware-centric project) with good schematics that you could usefor inspiration to get a custom design up and running. For the ignition only one, you'd almost be a fool not to just buy a TA card and put a minimal power supply and IO setup on a small piece of prototyping/vero board. Here are some examples of DIY hardware builds based on the TA card:

http://www.facebook.com/media/set/?set= ... 021&type=1

I hope that helps :-)

Fred.

I agree with the addition of other sensors but this particular bike has the old direct cable pull slide type carbs so TPS is not likely. I thought that a map sensor would closely resemble a TPS. This is an air cooled bike so I could use a temp sensor in the oil. Dual TPS is possible due to synyc ports An IAP sensor isnt a bad Idea

1...what is the foot print of the standard unit?
2...how close does the MAP sensor follow the TPS? (TPS usually contain idle validation circuit, rheostat/potentiometer, and possibly a WOT validation)
is this why I should have a TPS.
3...knock sensor? mounted on lower case
4...this engine will spin up to 9500 rpm
5...this engine is a chain drive SOHC with a poor cam chain tensioner so the cam tends to surge just thought a CMP would be a poor idea but I can upgrade the
tensioner if that is a better option
6...I have 6 of these bikes and am looking setting all of them up with a system, I have always liked the hands on approach to repair and upgrades.
I have been a mechanic for many years anything from lawnmowers to unmanned aircraft. That being said I haven't been to this level of electronics before. I have always been interested but never had the time. So

I am already divorced so that threat is mute................. strike one
I am single so I determine my cash flow....................... strike two
my kids(20,20,18,16) wont let me date.lots of time....... strike three

Thanks Again
V/R
Riksoto

1) The TA board is 3.25 inches long and 2.3 inches wide. I'd say it's about 3/4 of an inch high, but it depends on which connectors you get.
2) MAP trails TPS a little bit. Honestly I don't think a TPS would be worth the work since you'll probably have to put a throttle body with a TPS on it for the fuel injection anyway.
3) I have a knock sensor hooked up to my board right now, but it's a feature that hasn't had any code written for it yet.
4) I imagine you could get away with all sorts of different trigger wheel patterns, so use something you can get several of easily since you want 6 of these setups. Fred could give you a good idea of a range that'll work, because I have no idea.
5) Probably wouldn't be a bad idea, but I doubt it would be necessary.
6) It's not too bad if you have a fair amount of patience, and are relatively detail oriented.

Rikisoto, firstly:

I am already divorced so that threat is mute................. strike one
I am single so I determine my cash flow....................... strike two
my kids(20,20,18,16) wont let me date.lots of time....... strike three

ROFL!!! :-) That reminds me of when I was a teenager and didn't want Dad to date. He got around anyway, and good on him. The funniest thing was when he came home with a phone number on his tshirt. I noticed it before he wok up and had it clean and phone-number free by the time he woke up. Pissing myself laughing right now, but IIRC, he wasn't impressed :-) Show your kids this, they'll laugh, and maybe learn to lighten up on you?

Riksoto wrote:I agree with the addition of other sensors but this particular bike has the old direct cable pull slide type carbs so TPS is not likely.

No problem. It's always about how well you can tune it and how well it'll run, not IF it'll run. Try it and see how you go. Upgrading to programmable ignition is typically a good gain regardless.

I thought that a map sensor would closely resemble a TPS.

Kind of, not really. Imagine the airflow requirement of the engine at idle RPM, not much, so a minimal TPS opening will satisfy that properly and produce close to 100kPa. Now imagine that same opening at 8k RPM, your airflow need is MUCH higher, so the restriction is a problem and you'll draw something of a vacuum in there despite the throttle being partly open. Hopefully that helps.

The trouble is that the MAP readings you get will be crappy unless taken VERY carefully. How many cylinders is the bike? You may need MAP per cylinder to get good numbers from it.

This is an air cooled bike so I could use a temp sensor in the oil.

Oil is slow to respond, you're better off with a sensor in the head casting as close to the chamber as you can get, inside the rocker cover, or near where the sleeves meet the head, etc. The numbers themselves don't matter, you can use legit head temperatures, no problem, but the lag/response does.

1...what is the foot print of the standard unit?

There is no standard unit, but as Peter pointed out, the TA is pretty small and could easily handle your ign only task with a board the same size plugged in to it and nothing else.

2...how close does the MAP sensor follow the TPS? (TPS usually contain idle validation circuit, rheostat/potentiometer, and possibly a WOT validation)
is this why I should have a TPS.

No, the reason is that without a shared plenum the pressure fluctuates WILDLY and you have to time your readings very well or you see no vacuum or a lot of noise in the signal. You can't really smooth the signal either, as the average is high pressure, and you really need the peak of vacuum for a good tune.

3...knock sensor? mounted on lower case

Unimportant unless you're careless with which fuel you use, and even then, it's only a crutch. We'll support it eventually, but it's never that useful. I remember when I was getting into this 14? years ago, I thought knock sensing was the most important thing ever too. The truth is quite the opposite, though, especially on high output boosted engines.

4...this engine will spin up to 9500 rpm

Something in the 12 - 24 tooth range with one missing would be good at the moment, higher later, but not yet. Right now 12-1 gets you 13500 max IIRC. However, what you find on high revving sports bikes is evenly spaced teeth on the crank and a cam sync. Typically low counts, too. R1 has 8 even teeth on the crank and a cam sync, for example. This keeps the CPU load down at higher revs. However...

5...this engine is a chain drive SOHC with a poor cam chain tensioner so the cam tends to surge just thought a CMP would be a poor idea but I can upgrade the tensioner if that is a better option

This is a problem, especially if the slop takes your sync pulse back and forward over a crank tooth edge. I've got some code in the works to make it less of a problem, however it could still screw you, no matter what, if you're using an even teeth setup.

So maybe 12 minus 1 is a good choice for the time being?

6...I have 6 of these bikes and am looking setting all of them up with a system, I have always liked the hands on approach to repair and upgrades.
I have been a mechanic for many years anything from lawnmowers to unmanned aircraft. That being said I haven't been to this level of electronics before. I have always been interested but never had the time. So

Cool! :-)

I hope that helps!

Fred.

What is the most current, most supported, and confirmed hardware?

Is there a complete material list?

I am ready to buy parts and start losing my hair, ok finish losing my hair

Will a single tooth on the flywheel work for my project?
There is a single tooth on my flywheel and I have a mount for a hall sensor built on the stator mount. I could use a CMP to determine #1 cylinder.
this is a common trigger system on motorcycles.

The bike is kick start only, so 720* of crankshaft rotation is max for starting and 360 would be better but I think it would only work if the engine is on the compression
stroke of #1 cylinder before the trigger on crank and cam.

I did some homework on factory and aftermarket ignition systems and recorded several curves so now I have a list of curves to choose from and modify to create the optimum curve for a modified engine.

Thanks in advance
V/R
Riksoto

Sorry for the delay!

Re the hardware, take a look at Sim's DIY build and Peter's DIY build, they're good examples. There isn't a standard hardware solution, partly because everyone has different needs and partly because none of them are finalised yet. Some are getting close now, though, and there is certainly nothing to stop you from putting something together DIY style as most of the others have done.

Single tooth has some specific requirements:

1) It is timed accurately so that that timing can just be used during starting
2) There is code available to "hard code" the ignition output to that single input

2 isn't currently true in FreeEMS mainly because it was never intended for low-end systems with inferior coarse input patterns. It could be added, but there are many other priorities so it won't happen remotely soon.

Kick start is an interesting problem to solve, but one that I'm confident we can lick. You're definitely not going to want to rely on a cam signal for sync with that being the case, so I refer to my earlier 12-1 suggestion. This will get you a sync inside 360 degrees and fire the next time it makes sense to. Current code is pretty eager to start on cars, however it still might be a bit slow for you.

In summary, if you do go in for this, expect to have to be about twice as patient as everyone else because your case, simple as it is, has some difficult requirements that aren't high on the list. IE, there will be a lot of waiting. I don't want to see you be disappointed when 6 months later it still doesn't work adequately for you, for example.

Sorry for the bleak outlook! :-(

Fred.

I recently found all of this wonderful information that is Free EMS and diyefi and thought that it might be able to solve a few of my current issues and later tackle some more complex projects.
Currently I would like to tackle a project near identical to this thread. I have a 1978 Honda CB 400 motorcycle. That is a 400cc twin cylinder aircooled bike with unreliable capacitive discharge ignition. I would like to run a very basic ignition only circuit. I do not want any MAP sensors or anything of the sort. I just want a basic advance curve from starting rpm to 14000 rpm. This thread seemed like a great start, so I would like to finish it.
I am looking for a good starting point. I have read a little about the TA card but cannot find enough information on it to start. I'm also unsure on crank position sensing. I have seen that I need some sort of reluctor wheel(12-1 like mentioned above), but what sensor do I need to read that?

sorry for the rant, but I look forward to building something,

-Steve

Welcome along!

What position sensors does the bike currently use? That's the first step. They may still be usable.

The trouble with simple inputs and current code is bad accuracy when starting; very bad. Fine at higher RPM, though.

The trouble with high tooth count inputs and the current code is that it's too inefficient to rev high. Fine at lower RPM, though.

Hence my 12-1 suggestion, if you must have a missing tooth setup, that's a good compromise.

14k would be the highest anyone has gone so far :-)

Fred.

It has a strange magnetic pickup with the magnet on the flywheel. The pickup has what looks like two pickups that I think help with timing advance. I am not certain, but one of the parts in the system has failed. I have narrowed it down to the cdi module or the pickup. The coil is shared between both cylinders, so I just need to trigger it once very 360. I mispoke in the last post. The redline is 12000 rpm not 14000.

Just out of curiosity at this point, what would you read the missing tooth wheel with?

thanks,