DT175MX won't start

[philhill]

Hi, can anyone help, DT was running fine then went on holiday and when i got back i tried to get it going and it wont start. Previously a good starter, now no spark. Have tried a new 'cheap' coil they sold me down the local bike shop for 20 quid which doesn't fit properly and a new spark plug, checked the connections, earth connector wire to the metal frame of the coil was chaffed and rubbing on the frame, but I presume this doesnt matter as its the earth, repaired anyway. Connected a meter set to voltage, to the input and earth and it sends the digits wizzing when i push the kick starter, but don't know what it read! Bit stuck now, electrics not my thing. Anyone know what to try next? Neither of my bikes are working at the moment and want to get back out on the road! Thanks Phil

[Airhead]

Try a different spark plug Phil

[philhill]

Try a different spark plug Phil

Hi, have tried a new plug and 2 old ones but still no spark, have put the old coil back on.... no spark. Checked kill switch as I regularly forget and can't remember which way it should go, with 'OFF' written in the ON (up)position. I checked electrical continuity with switch UP, showing the red square at the bottom and its passing current through. So I must be right, Yes?

Anyway what do I check next? Hope its not the CDI gone wrong as just checked and they are £180!!!!!!

HELP haven't ridden a bike for 5 weeks and getting withdrawal symptoms.

Phil

[Airhead]

Hi, have tried a new plug and 2 old ones but still no spark, have put the old coil back on.... no spark. Checked kill switch as I regularly forget and can't remember which way it should go, with 'OFF' written in the ON (up)position. I checked electrical continuity with switch UP, showing the red square at the bottom and its passing current through. So I must be right, Yes?

Anyway what do I check next? Hope its not the CDI gone wrong as just checked and they are £180!!!!!!

HELP haven't ridden a bike for 5 weeks and getting withdrawal symptoms.

Phil

unplug the orange wire from the coil.

Measure the resistance of the coil secondary from inside the connector in the HT cap...to the battery negative terminal

measure the coil primary orange wire to the battery negative terminal

What do you get?

are they within spec?

[philhill]

unplug the orange wire from the coil.

Measure the resistance of the coil secondary from inside the..to the battery negative terminal

measure the coil primary orange wire to the battery negative terminal

What do you get?

are they within spec?

'connector in the HT cap.'do you mean spark plug cap? Phil

[Airhead]

'connector in the HT cap.'do you mean spark plug cap? Phil

ok I was in a rush before so didnt think about it properly.

The HT cap (AKA spark plug cap)

unscrew it off the HT lead, it is supposed to be a resistor cap so should be around 5K Ohms

The ignition coil primary...Orange wire to battery neg should be 1 Ohm +- 10%

The ignition coil secondary...HT lead to battery neg should be 5900 Ohms +- 20%

If the readings are much higher, check the ignition coil has a clean ground connection.

[blackhat250]

'connector in the HT cap.'do you mean spark plug cap? Phil

Yeh phill he does" , while there screw it off and check wire inside is making contact with thread on cap[ ie is ther wire showing up centre of HT lead] it may need trimmed , but not too much as will not reach plug

[philhill]

ok I was in a rush before so didnt think about it properly.

The HT cap (AKA spark plug cap)

unscrew it off the HT lead, it is supposed to be a resistor cap so should be around 5K Ohms

The ignition coil primary...Orange wire to battery neg should be 1 Ohm +- 10%

The ignition coil secondary...HT lead to battery neg should be 5900 Ohms +- 20%

If the readings are much higher, check the ignition coil has a clean ground connection.

Hi Paul (i think this is you name if i remember right, sorry if not), thanks, I am getting figures very similar to this, so where do I try next?

Phil

[philhill]

Yeh phill he does" , while there screw it off and check wire inside is making contact with thread on cap[ ie is ther wire showing up centre of HT lead] it may need trimmed , but not too much as will not reach plug

Hi, yes have tried this and have also trimmed the end. Also checked the cap for continuity and there wasnt any so tried a spare and another and they where all the same so assume this is correct and the spark has to jump across inside the cap somehow. (You learn something everyday!)Phil

I also tried putting the volt meter across the orange input wire and earth and kicking over. On the 2v scale I am getting 0.05 resting, and up to 1.4 when kicking over, it doesnt seem like enough power and doesnt appear to matter if the ignition is off or on or if the kill switch is off or on i still get same readings! Does this make any sense to anyone? Phil

[Airhead]

Hi, yes have tried this and have also trimmed the end. Also checked the cap for continuity and there wasnt any so tried a spare and another and they where all the same so assume this is correct and the spark has to jump across inside the cap somehow. (You learn something everyday!)Phil

I also tried putting the volt meter across the orange input wire and earth and kicking over. On the 2v scale I am getting 0.05 resting, and up to 1.4 when kicking over, it doesnt seem like enough power and doesnt appear to matter if the ignition is off or on or if the kill switch is off or on i still get same readings! Does this make any sense to anyone? Phil

First thing...Has the magneto flywheel woodruff key sheared?

Then disconnect the main switch and the Blk/Wht wire from the kill switch (in the headlamp shell?)

try again for spark

[philhill]

First thing...Has the magneto flywheel woodruff key sheared?

Then disconnect the main switch and the Blk/Wht wire from the kill switch (in the headlamp shell?)

try again for spark

Hi Paul, flywheel is spinning fine and appears well attached. Have disconnected two connector blocks attached to the ignition switch and disconnected the black and white wire from Kill switch and still no spark. No idea what you were trying there but will keep following the instructions..!? Phil

[philhill]

Hi again, I gave up on the DT's no sparking to concentrate on a charging problem with my other bike. That's now fixed so its back to the DT. I have been out and bought a new (correct) coil and rectifier. The old rectifier when tested with a multimeter set to ohms, showed 1 or infinity (i believe this is the term?) both ways which according to the manual shows its faulty. The new one is just the same!!? The multimeter has a diode symbol for one of its settings, should I use this one, and what reading should I expect? Anyway putting these on has again made no difference. I checked the pulse coil resistance and this was 10.3 (ohms?) which manual says is ok. Checked continuity of the orange wire from CDI connection to the coil and this was ok. Checked the ignition switch worked, brown and red wires showed continuity at the connector in the headlight shell when switched on. Brown and black wires into the CDI show continuity with earth and not sure if they should? Stuck now, don't know what i am doing and what to try next, any suggestions? Phil

[burton500]

Hi, yes have tried this and have also trimmed the end. Also checked the cap for continuity and there wasnt any so tried a spare and another and they where all the same so assume this is correct and the spark has to jump across inside the cap somehow. (You learn something everyday!)

I've never heard of a spark inside the cap before - you sure about that?

Lee

[philhill]

I've never heard of a spark inside the cap before - you sure about that?

Lee

Hi Lee, no, not sure but just guessed that the spark must jump across inside somehow, as when i tested continuity with a multimeter there isn't any. I also crushed one to have a look inside and there is a 'fuse' type capsule inside. So presume that something happens inside it like a spark jumping across, don't really know, like i said just guessing. Somebody knowledgeable on these things might chip in with answer? Phil

[Cynic]

Hi again, I gave up on the DT's no sparking to concentrate on a charging problem with my other bike. That's now fixed so its back to the DT. I have been out and bought a new (correct) coil and rectifier. The old rectifier when tested with a multimeter set to ohms, showed 1 or infinity (i believe this is the term?) both ways which according to the manual shows its faulty. The new one is just the same!!? The multimeter has a diode symbol for one of its settings, should I use this one, and what reading should I expect? Anyway putting these on has again made no difference. I checked the pulse coil resistance and this was 10.3 (ohms?) which manual says is ok. Checked continuity of the orange wire from CDI connection to the coil and this was ok. Checked the ignition switch worked, brown and red wires showed continuity at the connector in the headlight shell when switched on. Brown and black wires into the CDI show continuity with earth and not sure if they should? Stuck now, don't know what i am doing and what to try next, any suggestions? Phil

This method offends the mechanical ideals of some peole but its basic and has worked for me more than once.

Make sure the battery is fully charged. Then rig up a couple of long jumper wires to run from the battery terminals, leave the - connected to the bike but disconnect the red (+). Connect the black(-) flylead to the threaded part at the bottom of the plug.

Disconnect the orange wire from the cdi, then using your new funky jumper lead (the red one) put power to the wire. Dont put the power into the CDI though eh.

If everything is good when you remove the power from the orange lead you will have a spark as you have just done manually what the cdi does many times a second.

If you have a spark you will have proved the main 'high tension' part of the system. We can then move on to other parts to work with. Also a question, do you have six wires to the CDI or seven?

You should have continuity in the cap. Showing around 4/5KOhms Are you sure you are using the meter correctly they can be very confusing.

[philhill]

This method offends the mechanical ideals of some peole but its basic and has worked for me more than once.

Make sure the battery is fully charged. Then rig up a couple of long jumper wires to run from the battery terminals, leave the - connected to the bike but disconnect the red (+). Connect the black(-) flylead to the threaded part at the bottom of the plug.

Disconnect the orange wire from the cdi, then using your new funky jumper lead (the red one) put power to the wire. Dont put the power into the CDI though eh.

If everything is good when you remove the power from the orange lead you will have a spark as you have just done manually what the cdi does many times a second.

If you have a spark you will have proved the main 'high tension' part of the system. We can then move on to other parts to work with. Also a question, do you have six wires to the CDI or seven?

You should have continuity in the cap. Showing around 4/5KOhms Are you sure you are using the meter correctly they can be very confusing.

Hi Cynic, thanks for the reply. Have got 3 wires in and 3 out. Checked the cap, yes have got 5.05 on 20k setting. Plug cap is now a black NGK off the Guzzi as original is rusty inside. Presume this wont make a difference? . Have done the jumper lead thing on a weak battery (now charging) and got a weak spark. Coil and plug are new. What do we do next? Phil

[Cynic]

Hi Cynic, thanks for the reply. Have got 3 wires in and 3 out. Checked the cap, yes have got 5.05 on 20k setting. Plug cap is now a black NGK off the Guzzi as original is rusty inside. Presume this wont make a difference? . Have done the jumper lead thing on a weak battery (now charging) and got a weak spark. Coil and plug are new. What do we do next? Phil

That is great, means the plug, cap, coil and the wires envolved are ok so they can be left for now.

Next, connect the orange wire back up and look at the cdi connections again. There will be a black and white, more a black with a white tracer.

Disconnect it. Reasons in PM

Do you get anything when you kick it over?

[philhill]

That is great, means the plug, cap, coil and the wires envolved are ok so they can be left for now.

Next, connect the orange wire back up and look at the cdi connections again. There will be a black and white, more a black with a white tracer.

Disconnect it. Reasons in PM

Do you get anything when you kick it over?

Hi Cynic, I got one spark first kick(push)over then nothing despite trying for ages, then reconnected b/w wire and got another single spark then nothing !? Sorry don't know what PM is. I am charging the battery just in case but i don't think its important here is it? Phil

PM=Personal mail, got it thanks

[Cynic]

Hi Cynic, I got one spark first kick(push)over then nothing despite trying for ages, then reconnected b/w wire and got another single spark then nothing !? Sorry don't know what PM is. I am charging the battery just in case but i don't think its important here is it? Phil

PM=Personal mail, got it thanks

No the battery has nothing to do with the starting in normal service. Its good to have it charged obviously.

I'd give all the cdi connections a good clean and make sure both the black wires has a good connection to earth (-). Don't mix them though as they are both separate, one runs into the mag the other earths the cdi. If either are dirty they will affect things.

Odd that you get one spark then nothing. So if you make and break the b/w wire does that keep the spark regular?

[philhill]

No the battery has nothing to do with the starting in normal service. Its good to have it charged obviously.

I'd give all the cdi connections a good clean and make sure both the black wires has a good connection to earth (-). Don't mix them though as they are both separate, one runs into the mag the other earths the cdi. If either are dirty they will affect things.

Odd that you get one spark then nothing. So if you make and break the b/w wire does that keep the spark regular?

Have tried breaking and remaking the B/W wire but no more luck with any sparking. Checked /cleaned the connections to the CDI tried again no luck. Don't know where these wires earth to but getting good continuity with earth. Phil