Project DTZr.....a DT125R love story
-
Have you checked the carb recently? Does it die at 5K rpm regardless of throttle position? I mean you can get it to rev over 5K just by cracking the throttle?
You’ve changed:
CDI
stator
Coil
Magnetic pickup
Plug
You’ve ruled out:
key ignition
Kill switchThere isn’t a lot left!
I’m wondering if the ‘feed’ wire to the coil (or to the CDI) has a break inside it? It can handle so much ‘pulse’ but breaks up its fidelity when it gets too much…
I can’t think of anything else @ the moment…
-
@SpookDog Throttle position plays no role,I've tried increasing rpm gently or wide open but it's the same.Definitely not carb related.
It must be electrical,it changes run time with temperature,last time it run a couple of minutes at 38 celcius,but 4-5 minutes a day with 31 celcius,both at idle speed.
I'll get spark plugs from another brand to try,4 NGK bought together maybe bad batch.
@Calum You mean the orange cable,both CDI's the same problem?Waiting for a second 4DL cdi from ebay,bought at a low price counter offer.
I 've checked resistance at everything,even for the ground points between spots.I'll refresh the soldering points at both stator's,maybe a joint is failing but shows continuity.
-
I know zip about electricity, so I am just guessing wildly, but what components are sensitive to timing? I mean, if the error is repeatably happening at 5000 rpm, then there should be something that depends on frequency, no?
Like not a spark plug as those happily ignite 20000 rpm with no mechanism that would make them fail at lower rates. Not switches because they either convey current or not, regardless of whether it would be a continuous voltage or a 1 µs pulse.
A rotor/stator could possibly fail if centrifugal forces make them lose shape or such? See anything possible loose there that may short-circuit at high rotational velocities? As for CDI, I have not the wildest idea how they work.
-
I know zip about electricity, so I am just guessing wildly, but what components are sensitive to timing? I mean, if the error is repeatably happening at 5000 rpm, then there should be something that depends on frequency, no?
Like not a spark plug as those happily ignite 20000 rpm with no mechanism that would make them fail at lower rates. Not switches because they either convey current or not, regardless of whether it would be a continuous voltage or a 1 µs pulse.
A rotor/stator could possibly fail if centrifugal forces make them lose shape or such? See anything possible loose there that may short-circuit at high rotational velocities? As for CDI, I have not the wildest idea how they work.
@Hark_Ptooie If the spark plug gap isn't set correctly than the spark can just break down at too high a load. The spark plug annodes are saturated with voltage from the HT coil, if the gap is incorrect then this will cause issues.
-
@SpookDog Throttle position plays no role,I've tried increasing rpm gently or wide open but it's the same.Definitely not carb related.
It must be electrical,it changes run time with temperature,last time it run a couple of minutes at 38 celcius,but 4-5 minutes a day with 31 celcius,both at idle speed.
I'll get spark plugs from another brand to try,4 NGK bought together maybe bad batch.
@Calum You mean the orange cable,both CDI's the same problem?Waiting for a second 4DL cdi from ebay,bought at a low price counter offer.
I 've checked resistance at everything,even for the ground points between spots.I'll refresh the soldering points at both stator's,maybe a joint is failing but shows continuity.
Only thing left is a break inside the wire. It might work ok until it hits a point where it just arcs. It doesn’t explain why it won’t start again though…
If you have a 3 coil stator and a side stand switch then you have little black box or boxes that controls the cutout. Under the seat near the air box… -
@Hark_Ptooie If the spark plug gap isn't set correctly than the spark can just break down at too high a load. The spark plug annodes are saturated with voltage from the HT coil, if the gap is incorrect then this will cause issues.
@Calum said in Project DTZr.....a DT125R love story:
@Hark_Ptooie If the spark plug gap isn't set correctly than the spark can just break down at too high a load. The spark plug annodes are saturated with voltage from the HT coil, if the gap is incorrect then this will cause issues.
Ah - makes sense.
-
@Hark_Ptooie I'll refresh the soldering as soon as possible because this problem drives me crazy.Everything is almost ready except this and cannot go for technical inspection.
@Calum I'll order a new spark plug cap from Yamaha dealer,although the current is within specs and the original one.I prefer to have a backup if not used
@SpookDog no such box on this model,It matches the cable harness of 3RN1 to 3RN9 of Haynes manual or the 3NC that @HOTSHOT-III posted to another thread if memory serves correctly.Side stand switch connects with negative and then to CDI blue/yellow.
-
@Calum Yep, happened to me as well!
The actual coil on DTRs is very good quality so it's well worth fitting a new lead even to an older one; you can cut off the very top of the coil's outer case where the lead pushes in with a junior hacksaw, pull out the old lead and solder the new one to the coil output for a really good connection. Then re-waterproof using Shoe Goo and electrical tape. Looks messy but no-one can see it under the tank.
I had a high-rpm misfire once, after trying everything else we replaced the HT lead in the manner described above which took around 1 hour on a summer's day so the engine was neither stone cold or up to temperature when I took it for a test ride. It wheelied out of the driveway without me even trying, and I couldn't believe how much better the performance was at all engine speeds. Made a big impression on me as I was 17 at the time and I'd spent practically a weekend trying to fix the bike and getting nowhere.
@HOTSHOT-III said in Project DTZr.....a DT125R love story:
The actual coil on DTRs is very good quality so it's well worth fitting a new lead even to an older one; you can cut off the very top of the coil's outer case where the lead pushes in with a junior hacksaw, pull out the old lead and solder the new one to the coil output for a really good connection. Then re-waterproof using Shoe Goo and electrical tape. Looks messy but no-one can see it under the tank.
Do you have any photo to see what you did,it's interesting to know,I have an old one with short cable.
-
@Hark_Ptooie I'll refresh the soldering as soon as possible because this problem drives me crazy.Everything is almost ready except this and cannot go for technical inspection.
@Calum I'll order a new spark plug cap from Yamaha dealer,although the current is within specs and the original one.I prefer to have a backup if not used
@SpookDog no such box on this model,It matches the cable harness of 3RN1 to 3RN9 of Haynes manual or the 3NC that @HOTSHOT-III posted to another thread if memory serves correctly.Side stand switch connects with negative and then to CDI blue/yellow.
Sorry to keep on asking about the side stand switch stuff. Your CDI must have an embedded controller…
If I was you I’d try: running a new wire from the magnetic pickup to the CDI, also the wire from the CDI to the coil. You’ve swapped out everything else electrical that I can think of for the time being…
The ‘resolution’ of the ignitions ‘pulse’ is loosing ‘fidelity’ somewhere. There can’t be that many places left to look… -
I didn’t realise you were still having this problem!
I need to go back over and read it again…Is your bike one of the ones deristricted with the read switch?…
Edit: Just read back some and I’m interested in the ‘sparks from side to centre’ bit.
Did you ever swap out the CDI?… -
@SpookDog 2 spark plug cap,another used working one and one without resistor inside.
Yes with 2 more CDI I bought.
There's a thread at electrical section,you replied there also,if memory serves.My memory doesn’t serve me very well bud!
If it’s still doing the weird spark I’d try replacing the orange wire that runs to the coil, as far back as possible. It sounds like you may have a break inside the insulation, that is causing a weak or intermittent spark…
No plug should spark like you stated when it’s dry and clean…
-
Pin the valve then if it still does it you know its not the servo
The black an white wire ( kill switch to cdi ignition ) can cause it to.spark every other kick.but yours is getting to 5000 rpm so I doubt it's that
One thing to remember half the wires in these looms the copper has turned black even though they look OK on the outside
