facebook1 youtube1 twitter1 instagram google plus linkedin1 pinterest1

logosmallNOTICE:  If you are not a free registered member of the site, you will not see the photos in the forum, and you won't be able to access our premium member content. Please consider joining our community!

Welcome, Guest
Username: Password: Remember me

TOPIC: Help No Spark 1975 Dt250

Help No Spark 1975 Dt250 02 Jul 2014 16:03 #1

  • Travisvt
  • Travisvt's Avatar Topic Author
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 18
  • Likes received: 3
So I got a bike from my buddy and last time he rode it went through a huge puddle and submerged the lower part of the engine.
He had no spark after and let the bike sit for a couple years.

I inherited it and have now been trying to slowly figure out whats wrong. So far I have put new points in and timed it.
Also put a new ignition switch on since my buddy lost the key, new battery, and am waiting on a new condenser. I Still no spark.

Any suggestions? Anyone have a way to test the stator and condenser, and maybe coil?

Thanks
Travis

Please Log in or Create an account to join the conversation.

Help No Spark 1975 Dt250 02 Jul 2014 16:58 #2

  • jdragun
  • jdragun's Avatar
  • Offline
  • Content Contributor
  • Content Contributor
  • Posts: 37
  • Likes received: 0
Testing the condenser (capacitor) is easy. With your multimeter, black to bottom, red to top and you should see the cap charging, with needle going up or in ohms going up. When hits top, swap the wires, it should go down. Be careful not to touch the top and sides with your hand together, will wap you.

You can put a meter on the black wire coming out and spin the fly wheele by hand and see if you are getting any voltage.

I don't know the resistances of the coil and ignition coils, but they are in the book I bet, I uploaded the 74 book, i bet they are the same.

Spark with a points system is pretty easy to diagnose out, not a lot of parts. Check the resistance on the coils and see if it's within tolerance.

John

Please Log in or Create an account to join the conversation.

Last Edit: by jdragun.

Re:Help No Spark 1975 Dt250 02 Jul 2014 18:05 #3

  • Travisvt
  • Travisvt's Avatar Topic Author
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 18
  • Likes received: 3
Thanks a lot John.

When you say "swap the wires" when explaining how to test the condenser, do you mean the red and black of the ulti meter?

Thanks

Please Log in or Create an account to join the conversation.

Re:Help No Spark 1975 Dt250 03 Jul 2014 02:18 #4

  • pntrbl
  • pntrbl's Avatar
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 835
  • Likes received: 259
FWIW, I chased spark for about a week when I brought mine home and it turned to be the spark plug itself.

Another potential trouble spot is the spark plug cap. Over the years they get can get disconnected where the wire meets the connector. A continuity check will tell the tale on that one.

Was there any excessive corrosion in the flywheel area after the water got in there? If so I suppose the stator could have a problem. The only guy I know of that can test and check them out completely is DEET. He spins them up somehow and checks for proper outputs from every coil.

Please Log in or Create an account to join the conversation.

Last Edit: by pntrbl.

Re:Help No Spark 1975 Dt250 03 Jul 2014 02:44 #5

  • Makotosun
  • Makotosun's Avatar
  • Offline
  • Site Administrator
  • Site Administrator
  • Admin is in the House!
  • Posts: 6615
  • Likes received: 2542
If you try everything else, and it is a stator issue, DEET is your man. He takes your whole system (coil, CDI box if electronic, stator AND your flywheel) when you get it back it will be better than original. You will want an acrylic side cover to show it off! It is important to test each component, as any one can cause your problem.

The spark plug and cap are good tips, and don't require age to be a problem. I had one new sealed plug from NGK that would not spark. They can be damaged if dropped on a cement floor.

Please Log in or Create an account to join the conversation.

You can tell a professional by the lack of wrinkles in his duct tape.

Re:Help No Spark 1975 Dt250 04 Jul 2014 14:50 #6

  • jdragun
  • jdragun's Avatar
  • Offline
  • Content Contributor
  • Content Contributor
  • Posts: 37
  • Likes received: 0
I just rewired the whole stator assembly, and all my resistances are perfect in there, but no spark Primary to the ignition coil is .8 to .9 a little on the low side, but ok, the Secondary, 0! No resistance at all. That is the reason I have no spark I'm guessing. The secondary wire looks a little dry rotted also, I don't see any sparks that jumped off to the frame, but with no resistance on the coil, That's a no good.

Travisvt, yes just swap the red and black, you should see the power drop all the way back down and then build back up.

Also pull the 4 wire block by the air filter box (Green, Green/red, yellow, black) and test resistance there, yellow to ground should be .25, green/red .35, and green 2.1. plus or minus 10%.......That way you know you have your lighting coil good......

Test your ignition coil just like I did, up under the tank, Primary (small black wire going in) 1.02 and secondary (to the spark plug) 5.9. (Mine was 0, dead coil)

Please Log in or Create an account to join the conversation.

Re:Help No Spark 1975 Dt250 04 Jul 2014 14:58 #7

  • Travisvt
  • Travisvt's Avatar Topic Author
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 18
  • Likes received: 3
Thanks a lot for the info Jdragun.

When checking the coil does it matter of it is connected to bike? Also do I just ground the black lead from my multi meter to the bike and use the red lead from my multi meter to the locations you specify? Sorry electric is something that I'm no good at.

Please Log in or Create an account to join the conversation.

Re:Help No Spark 1975 Dt250 04 Jul 2014 15:01 #8

  • Travisvt
  • Travisvt's Avatar Topic Author
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 18
  • Likes received: 3
I get .5 when testing black wire on coil and it doesn't even show on multi meter when I try the spark plug wire side

Please Log in or Create an account to join the conversation.

Re:Help No Spark 1975 Dt250 04 Jul 2014 15:27 #9

  • Travisvt
  • Travisvt's Avatar Topic Author
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 18
  • Likes received: 3
Ok so just tested my 4 wire block these were my results:
green 1.8
Green/red .4-.5
Black 1.8
Yellow .5

Not sure if those are up to par but let me know any opinions.

I have a feeling that it might be my ignition coil since I can't get anything outta the spark plug end and .5 where the black wire feeds into coil.

Thanks again

Please Log in or Create an account to join the conversation.

Re:Help No Spark 1975 Dt250 04 Jul 2014 16:30 #10

  • Meis
  • Meis's Avatar
  • Offline
  • Collector
  • Collector
  • Posts: 1837
  • Likes received: 808
I would check disconnect the black wire leading to the coil from the stator....
then measure the AC voltage on the black wire coming from the stator while you kick it over...

Please Log in or Create an account to join the conversation.

"Get Sideways ".....Meis
Moderators: DEETDevinDmanEnduronutMakotosunVinnieyamadminJames Hart