loudhvx, look inside

Hey, just contemplating making a datalogger for when I start tuning. I have an O2 guage with analog outs, and I figure I'll hook up a TPS in some way, they're both 0-5V so I'll just throw them into the ADC on my board. Trickier is getting an RPM input. What if I just take the raw signal from a coil, clip it to 5V, and put it directly into a digital input on my board? I used a clipper circuit to accomplish the same a while back with the readout from a hall sensor. That'd probably work fine, right?

Probably going to use PIC micro controller since thats what I'm used to. Not sure if you're into this stuff, wanted to bounce it off someone who might know.

No eBay APP ID and/or Cert ID defined in Kunena configurationNot Lou, and I don't know anything about clipper circuits, and you probably already know about these, but just in case you don't:



Just sayin'
It does everything you want and then some. Can you build your own cheaper? I know it's probably an engineering exercise, and I respect that. Maybe you already have half the components, and can build it cheaper. Oh yeah, the LM-2 also includes some fairly powerful logging and analysis software.

Yeah I already shelled out for an innovate afr, but I wanted a gauge and not the bulky LM2. And this datalogging will just be an add on since the board will already be there to run my RFID keyless ignition. :woohoo: :silly:

Hard part is gonna be rigging up a throttle position sensor on a set of BS34's haha.

Let me look at my 34s when I get home. I did it on a set of VM26's but I'm having a hard time remembering what the bellcrank looks like on the 34s. I have some ideas.

Cool, let me know what you think. I was thinking of tapping the end of the butterfly linkage and threading in a post, then making some kind of mount for the tps that connects to the bottom bracket.

That was one of the ideas that seemed like it would work, but I never tried that one.

Yeah its a bit of a bitch but I really want to be able to datalog all my rides this fall, really get the bike dialed in. She wont be going till sometime in October though so I have a bit of time to figure all this stuff out.

I'm really looking forward to reading spreadsheets instead of spark plugs haha.

Spark plug color readings are not so good anyway. E10 doesn't give the same colors as pure gasoline.

I just looked at those BS34s. My solution from the VM26s is a no-go. The bellcrank on the 26s has a large area on the push cable side that I mounted a linkage to. I mounted the sensor on a sheet metal bracket built off the top of the #3 carb. I connected the sensor to the throttle bellcrank with a small turnbuckle that I sourced from RC car parts. Since the 34s don't have a push cable, there is no such area. You may have to stick with your original idea or maybe something mounted to the grip? I don't know if you plan on this being a permanent installation or not.

Here's a pic of the setup that I used on the VM26:

E10? None of that up here buddy. My 34's have a push cable, what are yours from?

I think that the set I have came from a Suzuki GS.

So you guys don't get the 10% ethanol? Pure gas is getting very hard to find in the States. I'm jealous.

The wire that goes from the coil to the igniter (or points) is a very unique part of the electrical system. It would seem to be just switching 12v on and off, but that's not exactly what happens. When the points, or the igniter, tries to stop current from flowing in the coil, the coil induces up to 600v on that wire. (That's why points arc so much if the condenser fails.)

So you can't really just clip the signal. But I assume you mean to isolate the signal then clip the isolated portion of the signal. That should be relatively simple, but the design will depend on how the input to the datalogger is set up. The only problem I see is if you use diodes to block the high voltage, then you may need a pullup resistor to activate the input in the datalogger. If the datalogger's input floats high, with a strong enough pullup, then you could just use a high voltage diode as a blocker, and a clipping Zener for safety.

Here's the first thing I would try:
The diode blocks the high voltage, but lets the igniter pull down the voltage. It will only pull down to about 2v, so hopefully that is low enough. If not, I'd throw a transistor at it.
The resistor pulls the signal high whenever the diode is not pulling it low. The zener diode clips the 12v down to 5v ~ 5.1v.




At one point Radio Shack would have had all of those parts. They should have the resistor or diode options listed, but the 5v zener may be a problem. If you can't get the zener, the same thing could be done with a resistor, but you'd have to experiment to get the right value since we don't know what the input of the datalogger is like.

I was considering the LM-2 when I got my wideband setup, but I read a few reviews with some complaints, so I just stuck with the basic LC-1.

Also, be aware that the rotational movement of the throttle shaft doesn't necessarily equate to a constant relationship with the mechanical slide's movement. I think most carbs are setup to keep the throttle shaft movement as close to a constant ratio to the slide's movement, but it doesn't necessarily have to be so.

On my TK's, I had to calculate the difference. It's very small, but if you are off by 1/16th of full throttle movement, you can be into a different circuit on the carbs.

I suppose, with trial and error, you'll know what the relationship is between throttle position and carb circuit involved so eventually it will become apparent.

It's also important to know where the slide is at WOT. On the TK-22 carbs I often see them opened beyond the top of the bore when they hit the WOT stop. This makes it get extra rich right at WOT, even if it's lean at 7/8 WOT. For tuning, I usually set the slide just flush at WOT. Then if it needs a little more richness at WOT, you can reset the slide higher at the WOT stop.