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No spark - Bad CDI or pickup coil?
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Hi there, I'm new to the forum but its been a valuable resource for me since I got my 2002 TTR250 a couple weeks ago. I bought it non-running for $250, but its in good condition and seemed to be a simple job. I expected stator or CDI. I got it home and was doing all the necessary voltage and resistance readings and discovered my pickup coil had no continuity. I figured that must be the cause, because everything else checked out OK, resistance-wise. Of course, thats not a very good method of verifying a part's health, but for the CDI and pickup, thats all I know to do. I ordered an after-market stator and pickup, and both test well. I installed and unplugged the pickup from the loom and put my test probes into the connector. I'm reading about .03 volts DC as I hit the starter. My questions are these: how much voltage should the pickup be sending to the CDI? Is there any way to verify my CDI is good? I cant swap it, I don't know anyone else with a TTR. Is there another pickup i can buy that might be able to cross over to my bike? I have seen in other forums that someone had considered using one from, I believe, a Yamaha Grizzly. Would that work since the stator and pickup aren't sold separately? I'm about stumped on this. Any help would be greatly appreciated! Thanks!



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The pick up is just a trigger pulse  I haven’t had to check mine so not sure of the voltage 

my first check is always the kill switch or wiring  (side stand switch )I’ve had moisture and dirt in the kill switch play up in the past 

 

agree ohm meter checks arnt 100% but a starting point  its Always hard to find parts to swap 



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Hi Elijah and welcome to the forum biggrin

No need to message me as I am reading all the forum messages and helping where I can! Also it's best to keep Q&As on the forum so that other owners who may have experienced a similar problem can, hopefully, share their solution with us all wink

Yours is not a problem that I have personally experienced and I am hoping that someone will come forward with a solution e.g. I recollect that Jean Louis (Bike Raid Laos) had a pickup fail and was able to buy a replacement pick up that fitted and solved his issue - see http://ttr250.activeboard.com/t62021383/ignition-pickup-coil-or-sensor-replacement/ 

Firstly, the TTR250 workshop manual is excellent and should have all the values you need to check. Have you had a look?

To get a copy quickly the manual for the plastic tank models is available online from Steve here https://estore-sslserver.eu/totallyttrs.com/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectPath=/Shops/699105d9-e4cc-4b32-b236-84e72cd67f84/Products/TTR-0203

I hope that helps.

Brian



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ttboof- thank you for those thoughts!! Yes I have checked the wiring and the safety switches with a meter, and to my knowledge, the starter motor won't try to turn if they are faulty so that, to me, verifies that the switches checks out. I'll check them again though for sure.

Brian- thank you for the greeting and ideas!! Yes I've checked the manual and as far as I could find, the only values for the parts in question are resistance values which do check out properly. I'm concerned that the pickup isn't sending a strong enough pulse to tell the CDI to fire the plug. Yes that link you mentioned is the very one I was referring to haha. So do you happen to know specifically what he bought that worked out? I'd like to buy the same and try it on minesmile Thnk you guys so much for your help. I'm sure I must be missing something and it's great to have other minds on the case!



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Hello again!

I trawled back through my old emails and found one that suggests that I had a damaged stator and took the pickup off that to send to Laos - so not much help to you - sorry disbelief

I am lucky enough to have spare parts and usually am able to diagnose problems by swapping out suspect parts until I sort a problem. I realise that isn't possible for you cry

Are you not getting a spark with the replacement stator and pickup?

Brian



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Thank you Brian for doing that digging for me!! It's ok though, I'm glad you were able to help him out! Yes exactly, I'm not getting a spark from my new stator and pickup. I do know that the ignition coil resistance value isn't quite in spec. I'm not sure if that would cause full loss of spark, I'd assumed it might just cause weak spark. But when I jumped it from the battery, it does give very bright spark at the plug so I know it's at least somewhat functional. Have you got any ideas for me to check? Or a hunch of what my problem might be? Thank you so much for your efforts!

 



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i think if you have a bright blue crisp spark now you have battery problems clean or new plug fresh fuel it should go just my thoughts possible turning over too slow reducing the spark john

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Ah John I appologize. I didn't phrase that very well. I meant that I took a wire, connected to the positive battery terminal, and directly brushed the coil to fire the plug. The battery and plug are both new and in good shape. Thank you for that thought though! Sadly I believe the problem is deeper than that.



-- Edited by Elijah Bronson on Sunday 14th of January 2018 09:40:02 PM

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so are you loosing the feed to the coil poss through ign switch or stop button

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Actually John I'm thinking I'm not getting any spark even from the CDI. When I unplug the orange wire off of the coil that comes from the CDI, and I press the starter no power is sent to the coil. But when I check the switches, it shows with my test light that the cutoff switch is working properly. Light on with the swith turned to run, light off when its off.

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Looking at the ignition trouble-shooter in the workshop manual, it sounds more and more like you have a faulty CDi.

Assuming you have completed all the other checks, particularly connections and continuity, the final solution box says "Replace the CDi unit."

Brian



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Brian, yes I went through that same troubleshooting guide. That's exactly what I was hoping the problem was not, haha. I guess I will be checking eBay now. Thank you guys so much! If anyone has any other thoughts for me to check on, I'd love to hear them! Thank you!

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Sorry it's taken me so long to pick up on this. Just been outside and checked continuity on the pickup coil on my bike. It has continuity, and reads 192 ohms resistance. The engine's out so I can't check what output it gives, but hope that helps in some way. Watching the youtube vid link I've just posted on the other cdi thread, it looks like the pulse trigger voltage is induced by a magnet passing through a coil momentarily, so I would guess the voltage will not be very high. I feel the need for Dr Google again...

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Ongoing discussion here http://ttr250.activeboard.com/forum.spark#comment-64292058



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Thank you mossproof, yeah my resistance is the same. I appreciate you getting that for me! I agree, I dont't think voltage would be very high.
Brian, thank you! Extremely helpful information! I'll be paying close attention to that thread, and if I have to buy a new CDi, maybe I'll try to crack into mine to see what is inside. I'm curious about what might fail or if it might be repairable in any way?
Thanks guys.

PS. I forgot to mention. There is no voltage coming out of the CDi and going to the coil on the orange wire while cranking. I saw you reference that in the other thread.



-- Edited by Elijah Bronson on Wednesday 17th of January 2018 09:01:29 PM

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yes the magnet induces a voltage in the winding in the pick up coil  ( ive never had to check a TTR but ones i have are from .2v to 3v ) , once the  pre determined voltage is recognised the cdi unit does its thing switching  the primary coil in the ign coil causing a secondary voltage - spark

CDI -- capacitor discharge ignition  , capacitor in the unit charges to a high voltage , the pick up coil triggers the unit and the voltage is dumped through the ign coil simple and complicated at the same time no

its a hard one to diagnose as Brian has indicated check the work shop specks and anything else you can before making a call on the cdi as they rarely fail  (but can do )

I haven't had to look at a ttr ignition so a bit of a mystery in regards to the fine detail ( fitting this reply in during a break in a business audit at work haven't had time  to look into it much ) 



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Elijah

One more check please!

Could you take off the CDi connector, switch on the ignition and check you have 12v at the Black/Red terminal on the loom side connector?

Brian



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Brian, I checked it out. Yes there is 12v going into the CDI, but no power comes out of it. I read your other post in the other thread and I'm inclined to agree. Pickup has nothing to do with the actual charge of the capacitor, but rather acts as a sensor for when to fire. For that reason I'm almost certain my CDI is bad. What do you think? Thanks!

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I am sorry to say that your CDi appears to be faulty cry

I can't think of any other checks to make....

Brian



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Thats what I was thinking too. Willl a NOS CDI from a 2000 bike work? Years won't matter will they? Thanks

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To the best of my knowledge the TTR250 CDis are interchangeable across all years and models.



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If its no bother, can someone tell me definitively that my pickup coil, at .05v, is alright and that it is not my problem? Thanks!

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id check but i put the bike back together yesterday  currently a little over 60 deg c  in the shed today .

 

 



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Elijah Bronson wrote:

If its no bother, can someone tell me definitively that my pickup coil, at .05v, is alright and that it is not my problem? Thanks!


 How are you measuring that - a multi-meter connected to the pickup connector whilst cranking the engine?



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Yes that's right. The two wire connecter that comes directly from the coil.

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the voltage is probably AC not DC , if your checking on DC voltage it will show lower than it should .

if some one can check the resistance ( should be close to the manual ) and the ac voltage when cranking with the pickup disconnected , both figures should be a good guide to identifying a good pick up .

 

 



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Well guys thank you so much. You've been loads of help!! I took her out for my first spin in the mud yesterday and it is just a blast to ride. Thank you for all your insight and assistance guys, I wasn't sure I'd ever get to ride it some days. My biggest problem was I bought a cheap stator from ebay, big mistake. I then got a refund because I determined it was faulty, cause it read only that .05 volt on both AC and DC. After I put in an RMStator, it fired right up. When I get home I'll post here a 15% off coupon they sent me, cause I found a coupon just like that that saved me $23. I also needed a CDI cause no power was being sent to the coil so I knew it was bad. Here are the rough values as I recall them:
With bad CDI: orange wire, key on, no cranking: 0v. Cranking: 0v.
Good CDI: orange wire, key on but not cranking: 60v DC. Cranking, nearly 200 DCV.
Good pickup coil: 200 ohms, .5 ACV while cranking.
Hope this will help someone in the future.
Thank you all so much again!!!

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great news your  ttr is out and about with you on it not pushing it biggrin they are a great  bike

thanks for the voltage figures they they match up with what Brian has helped put together , we may now have a fairly accurate way if checking the ign system to help with making  decisions a  bit easier .



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Good ending and lessons learnt all the way around methinks - thanks for great feedback and your persistence biggrinbiggrin



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Great work, well done allsmile



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15%off $100 or more from RMStator: LBSW15

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