MicroSquirt.com read only forum (Jan.15,2018)

Well by looking at it, they looked 180 apart. When I drew a line through the photo you can see they are not, so there is one problem. Not sure if I have enough adjustment to compensate. If it is inverting one input that could also be a problem. This could explain why it looked like it one channel was capturing rising edge and the other trailing. I will have to measure how many degrees the it is from leading to trailing. But it does not explain why the 2nd channel offset could not fix it. Will see if I can get the sensors 180 apart and log again.

The sensors need to be placed where the engine wants them - if this is an odd-fire engine then they should be positioned to reflect that. But if it is even fire, then yes I would try to make them 180 deg apart. But i agree - we haven't explained why the offset doesn;t help - but once you determine what the offset should be, then we can run it with that offset entered in the data and, if it is still not right, see what the timing variables tell us.

If you hook the triggers back up to the Dyna box and set them both to 35 deg you will know that they are 180 deg apart, as that is how a CB750 fires.
The Dyna hall sensors allready have a pullup resistor, so they are at 3.75 V when the magnet is not present and drop to zero when it is. You said that you had installed a pullup resistor, maybe you don't need it.
I know this doesn't help your offset problems but maybe it will clear up some of the trigger confusion.
Aso I would put a meter on the hall outputs and see if they are both doing the same thing when the magnet passes them.
As I remember a CB 750 has a mechanical advance unit. Did you lock this.

The trigger mounts are not adjusted the same in their slots, if you even them up you may have 180 degrees. I can't see how it can't be 180, I doubt Honda changed their crankshaft to be offset some degrees.

Ian.

Mine is a dyna 2000 system, they dont have pull-ups, I checked it with a meter. They weren't that far off, I was able to set them up at 180 degrees apart and ran the datalogs. just FYI channel one on the opto-in goes from zero to 6volts and channel on vr2 goes from zero to 12 volts. both triggers are set at 40 degrees BTDC. With -320 offset, no where close with rising edge and calculated. Channel 2 is at 40 degrees BTDC. With 40 offset channel one is TDC and ch 2 is at 40 BTDC. These flip flop when changing to falling edge. All zeros in advance table and 2nd channel offset= 0.

wouldn't let me put more than 3 attachments in one post

This all looks consistent and shows what I expected. Both inputs and outputs show varying time differneces: roughly 636 and 960. If you add them up and multiply by .128 you get 204 ms, which is the time for 1 rev at 294 rpm. It's shows me that the spark outputs are reflecting the inputs and that the inputs are not coming in every 100 ms (spare 4 always around 781 or so) like they should, but they are in fact offset. This could be for several reasons. I notice in the picture that the sensors don't really look the same. If their polarities are different, then that would explain it. I know the Dyna 2000 works, but that is because the circuitry in that is designed for this and compensates. Or it may be the opto gives a different polarity - I will ask Bruce to weigh in on this. Or it could be that the wires on one sensor need to be reversed or it may be that where you think it is detecting/ zero crossing is not really where it is. If you just run the first data (-320 offset) but move ONE sensor in ONE direction, and rerun, then you should see the spare4, spare5 numbers either get closer together or further apart (like 500 and 1100 rather than the present 636, 960). You are trying to get both numbers to come out to around 780 for 300 rpm. That is, the spare4 column should have all it's number near 780 and likewise for spare 5.

The thing is, I can move the sensor on the channel that isnt working and it has no effect. I am going to try using vr1 instead of opto-in. There is a wheel behind the sensor plate that you can see through the hole. It is marked at tdc for 1/4 and tdc for2/3 with 0-40 btdc marks for each. I can hook a meter to the sensor outputs and watch them trigger at 40 degrees btdc for each channel as I turn the engine over by hand. I fyou say the outputs are as you expected then something is wrong between the sensors and input to controller, which the only thing I can think of is the opto circuit.

Do I need to use the hall effect ofsetter circuit described in the general info forum, to use vr 1?

Last night had some success. Switched channel one to the VR1 input with 1k pull up. Used the shield as input and grounded center (just read on the other post this should be reversed, will verify which pin its going to later) Seemed to have no effect. Set offset to -40 and channel 2 odd angle to -320 and they both fired at 40 degrees BTDC. With calculated set shouldn't this be using the advance table? I set the lowest rpm bins in the table to 200rpm,250,300 and all are set to 0. Then I set them to 10 degrees and only the channel one responded by adding another 10, channel 2 did not respond. So 2 questions, why is not firing at tdc with the 40 degree offsets and 2 why does channel 2 not respond to the advance table?