Author Topic: Questions about Fl250 ignition and cdi  (Read 6752 times)

2StrokeRebel75

  • Newbie
  • *
  • Posts: 8
  • Karma: 0
    • View Profile
Questions about Fl250 ignition and cdi
« on: July 22, 2012, 07:38:51 PM »
Hello i recently bought an 84 fl250 odyssey for cheap. needs parts but a good starting point. it needs the cdi box and ignition coil. i have an 84 atc 110 project. and i was wondering if i could just use the atc cdi and ignition. If not what other models will work on my fl250. all help is appreciated.

Thanks,
Evan

hoodlum

  • Administrator
  • Hero Member
  • *****
  • Posts: 857
  • Karma: 11
    • View Profile
Re: Questions about Fl250 ignition and cdi
« Reply #1 on: July 23, 2012, 05:57:16 AM »
No for sure on the cdi,and I doubt it on the coil...I don't know of any replacement on the cdi,but I am not very 250 savy either....

Hoodlum

LiveWire

  • Administrator
  • Hero Member
  • *****
  • Posts: 1025
  • Karma: 20
    • View Profile
    • 85 Honda Odyssey FL350 Parts
Re: Questions about Fl250 ignition and cdi
« Reply #2 on: July 23, 2012, 06:39:49 AM »
4 stroke CDI will have a different advance curve. 250s get parted out a lot. I would start by looking for the parts that actually go to it.

2StrokeRebel75

  • Newbie
  • *
  • Posts: 8
  • Karma: 0
    • View Profile
Re: Questions about Fl250 ignition and cdi
« Reply #3 on: July 24, 2012, 05:07:23 AM »
Alright Thanks!! Im going to a local motorcycle shop tonight and he has tons of parts so im sure ill find sometjing. Thanks for the responses!

easygoin4

  • Newbie
  • *
  • Posts: 6
  • Karma: 0
    • View Profile
Re: Questions about Fl250 ignition and cdi
« Reply #4 on: July 24, 2012, 09:41:36 AM »
Keep us posted on what you find and are going to use.
Let us know if you get it running.
Thanks

2StrokeRebel75

  • Newbie
  • *
  • Posts: 8
  • Karma: 0
    • View Profile
Re: Questions about Fl250 ignition and cdi
« Reply #5 on: July 27, 2012, 01:35:22 PM »
Went to a local atv/motorcycle shop (where i usually get my parts, owner is very helpful.) He said that the ignition is used on many other hondas including the fl250. He also said that being a 2 stroke and coming off of a 4 stroke means nothing. and that it can be used aswell. went home wired it up and works. need a little tweaking before shes ridable ;)  but Thanks to every i ne for the input.

Two Wheels & More.  Beech Grove, Indiana. Is the name of the shop.  great people.

LiveWire

  • Administrator
  • Hero Member
  • *****
  • Posts: 1025
  • Karma: 20
    • View Profile
    • 85 Honda Odyssey FL350 Parts
Re: Questions about Fl250 ignition and cdi
« Reply #6 on: July 27, 2012, 03:00:56 PM »
The ignition curve on a 4 stroke is very different than that of a 2 stroke. A 4 stroke will either continue to advance as RPMs climb, or at least top out and stay there. A 2 stroke ignition curve retards  after the RPM the pipe was tuned for. By backing off the advance, it raises exhaust gas temperature. The speed of sound varies with temperature. Higher temps makes the sound waves in the pipe travel faster which then makes the pipe tuned for a higher RPM. So the ignition curve is retarded at high RPM to broaden the usable power range of the engine. Now assuming the base advance is the same, it would likely not damage your engine not retarding at high RPM, you would simply lose top end power as the pulse wave in the pipe hits the exhaust port after it has already closed. Now let's get back to that assumption. You cannot technically advance the timing in an electronic ignition. That would be like predicting the future. The pulse trigger is what is advanced. The CDI has to delay the actual spark a certain amount of time after the trigger to get the right timing. Less of a delay now means advancing the timing from where it was previously. I would not assume that the advance position of the pulse trigger is the same between any 2 machines let alone between a 2 stroke and a 4 stroke. Therefore, your base advance may be way off and that could result in engine damage. You can do what you want, but make sure you are willing to accept the consequences of the assumptions being made.