CDI pickup coil timing?
#1
12-27-2007, 05:18 PM
CDI pickup coil timing?
Does anyone know where, in degrees, is the pickup coil positioned relative to TDC?
I'm guessing that's out around 42-45 degrees. It's at least 40 degrees out, otherwise the KLX250SR's CDI probably wouldn't work on the KLX250S.
I'm guessing that's out around 42-45 degrees. It's at least 40 degrees out, otherwise the KLX250SR's CDI probably wouldn't work on the KLX250S.
#2
12-27-2007, 06:17 PM
#3
12-27-2007, 08:48 PM
RE: CDI pickup coil timing?
Thanks Tony, but not quite what I'm looking for.
I'm interested in the timing into the CDI (i.e. the output of the pickup coil) rather than the timing out of the CDI (i.e. timing at the spark plug).
The pickup coil (which is part of the stator assembly) is mounted in a fixed position with respect to the turning magneto rotor. There's a fixed relationship between when the magnet built into the magneto rotor passes the pickup coil and TDC -- that's the spec that I'm after.
For instance, I found through searching on the web that a Yamaha TT600R's pickup coil is mounted a 58 degrees before TDC. That's interesting, but I'm looking for that number for our bike.
I'm interested in the timing into the CDI (i.e. the output of the pickup coil) rather than the timing out of the CDI (i.e. timing at the spark plug).
The pickup coil (which is part of the stator assembly) is mounted in a fixed position with respect to the turning magneto rotor. There's a fixed relationship between when the magnet built into the magneto rotor passes the pickup coil and TDC -- that's the spec that I'm after.
For instance, I found through searching on the web that a Yamaha TT600R's pickup coil is mounted a 58 degrees before TDC. That's interesting, but I'm looking for that number for our bike.
#5
12-27-2007, 09:22 PM
RE: CDI pickup coil timing?
ORIGINAL: vfrpilot
Now you've got me wondering what you're up to. What you got in mind Dan?
Now you've got me wondering what you're up to. What you got in mind Dan?
#6
12-27-2007, 09:48 PM
RE: CDI pickup coil timing?
A challenge. I hope that this project doesn't turn into one of those that I put on the shelf and never get back to, but its interesting and challenging enough to keep me interested for a while (some of that is going to depend upon how long it stays freezing with snow on the ground).
So here it is (the idea anyway): A custom built programmable CDI
Remember that KLX300R CDI I got off of ebay for twenty or so bucks? I was determined to figure out why I couldn't get it to work. I un-encapsulated it and backward engineered it as much as I could. Well, at least as much as to figure out that it'll never work on our bikes. The big stumbling block of that CDI is how it is powered (and more so, how it builds up charge on the capacitor) and how the KLX250S's is powered. AC for the KLX300R (remember that it doesn't have a battery) vs. DC for the KLX250S. The two are not compatible. (I think that Dean hypothesized this conclusion at some point in time). Furthermore, the circuit that handles the "KILL" function is totally incompatible too, hitting the KILL button will always blow the main fuse.
So I've been researching CDI's and how they work and how one might build their own. I'm currently playing with a microcontroller program that I got for a different bike. One of the parameters that needs to be accounted for is the time between the CDI receiving a pickup pulse and the earliest that a spark would be initiated. That time would be based upon where the pickup coil is in relationship to TDC.
I feel that this project is something that I can do. I've done a lot of electronic hardware and software hacking in the past. It more of a academic exercise than anything, but has a practical purpose and ties nicely together a couple of my hobbies.
So here it is (the idea anyway): A custom built programmable CDI
Remember that KLX300R CDI I got off of ebay for twenty or so bucks? I was determined to figure out why I couldn't get it to work. I un-encapsulated it and backward engineered it as much as I could. Well, at least as much as to figure out that it'll never work on our bikes. The big stumbling block of that CDI is how it is powered (and more so, how it builds up charge on the capacitor) and how the KLX250S's is powered. AC for the KLX300R (remember that it doesn't have a battery) vs. DC for the KLX250S. The two are not compatible. (I think that Dean hypothesized this conclusion at some point in time). Furthermore, the circuit that handles the "KILL" function is totally incompatible too, hitting the KILL button will always blow the main fuse.
So I've been researching CDI's and how they work and how one might build their own. I'm currently playing with a microcontroller program that I got for a different bike. One of the parameters that needs to be accounted for is the time between the CDI receiving a pickup pulse and the earliest that a spark would be initiated. That time would be based upon where the pickup coil is in relationship to TDC.
I feel that this project is something that I can do. I've done a lot of electronic hardware and software hacking in the past. It more of a academic exercise than anything, but has a practical purpose and ties nicely together a couple of my hobbies.
#7
12-27-2007, 10:21 PM
RE: CDI pickup coil timing?
ORIGINAL: mooredan
A challenge. I hope that this project doesn't turn into one of those that I put on the shelf and never get back to, but its interesting and challenging enough to keep me interested for a while (some of that is going to depend upon how long it stays freezing with snow on the ground).
So here it is (the idea anyway): A custom built programmable CDI
Remember that KLX300R CDI I got off of ebay for twenty or so bucks? I was determined to figure out why I couldn't get it to work. I un-encapsulated it and backward engineered it as much as I could. Well, at least as much as to figure out that it'll never work on our bikes. The big stumbling block of that CDI is how it is powered (and more so, how it builds up charge on the capacitor) and how the KLX250S's is powered. AC for the KLX300R (remember that it doesn't have a battery) vs. DC for the KLX250S. The two are not compatible. (I think that Dean hypothesized this conclusion at some point in time). Furthermore, the circuit that handles the "KILL" function is totally incompatible too, hitting the KILL button will always blow the main fuse.
So I've been researching CDI's and how they work and how one might build their own. I'm currently playing with a microcontroller program that I got for a different bike. One of the parameters that needs to be accounted for is the time between the CDI receiving a pickup pulse and the earliest that a spark would be initiated. That time would be based upon where the pickup coil is in relationship to TDC.
I feel that this project is something that I can do. I've done a lot of electronic hardware and software hacking in the past. It more of a academic exercise than anything, but has a practical purpose and ties nicely together a couple of my hobbies.
A challenge. I hope that this project doesn't turn into one of those that I put on the shelf and never get back to, but its interesting and challenging enough to keep me interested for a while (some of that is going to depend upon how long it stays freezing with snow on the ground).
So here it is (the idea anyway): A custom built programmable CDI
Remember that KLX300R CDI I got off of ebay for twenty or so bucks? I was determined to figure out why I couldn't get it to work. I un-encapsulated it and backward engineered it as much as I could. Well, at least as much as to figure out that it'll never work on our bikes. The big stumbling block of that CDI is how it is powered (and more so, how it builds up charge on the capacitor) and how the KLX250S's is powered. AC for the KLX300R (remember that it doesn't have a battery) vs. DC for the KLX250S. The two are not compatible. (I think that Dean hypothesized this conclusion at some point in time). Furthermore, the circuit that handles the "KILL" function is totally incompatible too, hitting the KILL button will always blow the main fuse.
So I've been researching CDI's and how they work and how one might build their own. I'm currently playing with a microcontroller program that I got for a different bike. One of the parameters that needs to be accounted for is the time between the CDI receiving a pickup pulse and the earliest that a spark would be initiated. That time would be based upon where the pickup coil is in relationship to TDC.
I feel that this project is something that I can do. I've done a lot of electronic hardware and software hacking in the past. It more of a academic exercise than anything, but has a practical purpose and ties nicely together a couple of my hobbies.
It will be interesting to see what you come-up with.
#8
12-27-2007, 11:27 PM
RE: CDI pickup coil timing?
Do you plan on keeping (using) the throttle position sensor input?
If not then HPI (Belgium) makes a performance programmable CDI for the KLR250 which I believe is a very similar unit to the KLX250S but with no TPS input.
If not then HPI (Belgium) makes a performance programmable CDI for the KLR250 which I believe is a very similar unit to the KLX250S but with no TPS input.
#9
12-28-2007, 05:35 AM
RE: CDI pickup coil timing?
I don't plan on using the TPS input on the design. Horse Power Ignition (http://www.hpi.be/index.htm) is an interesting site. It's possible that the CDI for the KLR250 could be used.
I downloaded their software (HPI TuneBox v2004) which programs their CDI and played with it a bit and it possible that I came across the answer I seek. The "Tooth" constant (I suspect that this is the pickup coil constant) for the KLR250 is reported to be 55 degrees.
I downloaded their software (HPI TuneBox v2004) which programs their CDI and played with it a bit and it possible that I came across the answer I seek. The "Tooth" constant (I suspect that this is the pickup coil constant) for the KLR250 is reported to be 55 degrees.
