KTM Forums banner

41 - 60 of 69 Posts

·
Registered
Joined
·
3 Posts
So the mechanic figured out what the problem was on my 250 xcw, it seems like my flywheel got damaged due to the stator that came loose. This caused a short and damaged my CDI(CDI is giving intermitted spark). So it seems like the big problem came from the flywheel. I bought flywheel, CDI and ignition coil off another bike, the parts will be here hopefully tomorrow. Will update you guys if all is good with the bike.

Quick question, the CDI I bought comes off a 300, would this cause any issues on my 250?
 

·
Dirt Wizard
Joined
·
4,339 Posts
Has anyone seen a voltage regulator short out and kill all grounds with positive volt while engine is cranking starter button pushed i have positive voltage on motor and frame soon as i let off the start button they go back to ground and ill get a spark when pick up coil is in position
That actually sounds more like earth leakage. Your bikes starter motor is trying to earth through the strongest earth point which should be the subframe via the earth terminal.
If it's trying to earth through the reg, it's probably fried the reg.
Poor earths and bad stators kill voltage regs.
I use to do a modification to all the carby 4 stroke ktm dirt bikes and that was a simple 5-6mm earth wire directly from the battery to one of the bolts holding the starter in. I have mentioned this mod 100's of times over the forum, but never heard back from anyone except maybe @ktmfreaky who I see was talking about the same modification in one of his posts.
The short earth strap is sh-thouse running onto the allow subframe. You either get a bad connection at the subframe or a bad connection at the bolts where the subframe bolts to the frame.
 

·
Dirt Wizard
Joined
·
4,339 Posts
So the mechanic figured out what the problem was on my 250 xcw, it seems like my flywheel got damaged due to the stator that came loose. This caused a short and damaged my CDI(CDI is giving intermitted spark). So it seems like the big problem came from the flywheel. I bought flywheel, CDI and ignition coil off another bike, the parts will be here hopefully tomorrow. Will update you guys if all is good with the bike.

Quick question, the CDI I bought comes off a 300, would this cause any issues on my 250?
Thats a good question. I see the part numbers are different, but they probably use the same stator and coil. Not sure.
 

·
Premium Member
Joined
·
2,706 Posts
So the mechanic figured out what the problem was on my 250 xcw, it seems like my flywheel got damaged due to the stator that came loose. This caused a short and damaged my CDI(CDI is giving intermitted spark). So it seems like the big problem came from the flywheel. I bought flywheel, CDI and ignition coil off another bike, the parts will be here hopefully tomorrow. Will update you guys if all is good with the bike.

Quick question, the CDI I bought comes off a 300, would this cause any issues on my 250?
I dont remember details of module interchangeability between 250 and 300 but I think 250 works poorly on 300 and 300 module on a 250 is real bad idea. Motor will start and run with either module. I suspect the ignition advance should be different for either motor. It would be logical for 300 to require more spark lead and faster advance curve due to larger chamber needing more and faster advance. This would likely be bad for the 250 as it could lead to detonation and possible engine damage. I would be careful with that module swap. Watch carefully for pinging or detonation
 
  • Like
Reactions: Axzon and DW

·
Super Moderator
Joined
·
1,753 Posts
I dont remember details of module interchangeability between 250 and 300 but I think 250 works poorly on 300 and 300 module on a 250 is real bad idea. Motor will start and run with either module. I suspect the ignition advance should be different for either motor. It would be logical for 300 to require more spark lead and faster advance curve due to larger chamber needing more and faster advance. This would likely be bad for the 250 as it could lead to detonation and possible engine damage. I would be careful with that module swap. Watch carefully for pinging or detonation
Fully support @augiedoggie in this. If you fit the 300 CDI to the 250 you will find out if you have found the issue on the bike. But my recommendation is NOT to ride with a CDI that is NOT made for your bike. Our 2012 125sx's CDI died and we fitted one from our 2016 125sx. The bike ran well and we walked away with a top podium, but the spark melted the top of the piston... I bought the right CDI, fitted a new piston and had no issues.
 

·
Registered
Joined
·
3 Posts
I dont remember details of module interchangeability between 250 and 300 but I think 250 works poorly on 300 and 300 module on a 250 is real bad idea. Motor will start and run with either module. I suspect the ignition advance should be different for either motor. It would be logical for 300 to require more spark lead and faster advance curve due to larger chamber needing more and faster advance. This would likely be bad for the 250 as it could lead to detonation and possible engine damage. I would be careful with that module swap. Watch carefully for pinging or detonation
Thanks for the advise. I will then rather wait for the correct CDI.
 

·
Registered
Joined
·
34 Posts
Discussion Starter #47
That actually sounds more like earth leakage. Your bikes starter motor is trying to earth through the strongest earth point which should be the subframe via the earth terminal.
If it's trying to earth through the reg, it's probably fried the reg.
Poor earths and bad stators kill voltage regs.
I use to do a modification to all the carby 4 stroke ktm dirt bikes and that was a simple 5-6mm earth wire directly from the battery to one of the bolts holding the starter in. I have mentioned this mod 100's of times over the forum, but never heard back from anyone except maybe @ktmfreaky who I see was talking about the same modification in one of his posts.
The short earth strap is sh-thouse running onto the allow subframe. You either get a bad connection at the subframe or a bad connection at the bolts where the subframe bolts to the frame.
When i bought the bike it didn't have a battery in it so charge and no where to go definitely didn't help none waiting for parts now
Thats a good question. I see the part numbers are different, but they probably use the same stator and coil. Not sure.
Is there anyway to test flywheel ive replaced cdi stator added ground to starter went through the whole harness that the only thing that has not been replaced what are the chances of that being bad and does anyone know what the voltage from pickup coi is supposed to be
 

·
Registered
Joined
·
34 Posts
Discussion Starter #48
Can you adjust pulsar coil/ pickup coil ive got low signal 0.1ac is the best i can get out off it or do i need to replace flywheel
 

·
Registered
Joined
·
34 Posts
Discussion Starter #49
2008 xcw low voltage from pickup every thing is new stator cdi checked harness coil good wire good cap good plug good can you adjust pulsar to get a better signal or just replace flywheel
 

·
Super Moderator
Joined
·
1,753 Posts
Can you adjust pulsar coil/ pickup coil ive got low signal 0.1ac is the best i can get out off it or do i need to replace flywheel
The pulsar signal is created for the CDI only. The pick-up-sensor that sits next to the flywheel either works or it does not work. You can measure the sensor with an ohm meter. If the reading is low then the sensor is ok. When the flywheel turns and activates the sensor the signal goes to the CDI that then does it's magic and send out the signal so that a spark is created.
 

·
Super Moderator
Joined
·
1,753 Posts
Have you tried disconnecting the kill switch?
 

·
Registered
Joined
·
34 Posts
Discussion Starter #52
Have you tried disconnecting the kill switch?
Yea kill switch unplugged only thing that isnt new is flywheel get good voltage from exiter charge and lightning coil low output from pulsar can pickup be worn
 

·
Registered
Joined
·
34 Posts
Discussion Starter #53
That actually sounds more like earth leakage. Your bikes starter motor is trying to earth through the strongest earth point which should be the subframe via the earth terminal.
If it's trying to earth through the reg, it's probably fried the reg.
Poor earths and bad stators kill voltage regs.
I use to do a modification to all the carby 4 stroke ktm dirt bikes and that was a simple 5-6mm earth wire directly from the battery to one of the bolts holding the starter in. I have mentioned this mod 100's of times over the forum, but never heard back from anyone except maybe @ktmfreaky who I see was talking about the same modification in one of his posts.
The short earth strap is sh-thouse running onto the allow subframe. You either get a bad connection at the subframe or a bad connection at the bolts where the subframe bolts to the frame.
Still no luck stumped replaced everything except flywheel checked ground s added ground to starter new voltage reg ohmed whole harness with no issues
 

Attachments

·
Super Moderator
Joined
·
1,753 Posts
Yea kill switch unplugged only thing that isnt new is flywheel get good voltage from exiter charge and lightning coil low output from pulsar can pickup be worn
When you have come to the bottom of the barrel re logical solutions, then anything is worth a go! Only issue we have had with the pick-up-sensor has been a loose wire that we fixed by soldering.

Also worth mentioning is that we have tried after-market stators. Not been a successful solution for us. So when we have stator issues we replace them with OEM ones. The stators have been one of the main concern on the KTM's for us. I did a re-wind of one for a 85sx a few years ago. Took all night. Main problem was to get the old burnt one off as they are covered with some rock hard stuff that I ended up filing off to be able to rewind the bobbins.
 

·
Registered
Joined
·
34 Posts
Discussion Starter #55
Still no luck stumped replaced everything except flywheel checked ground s added ground to starter new voltage reg ohmed whole harness with no issues lil wearand small dent inside of flywheel
 

·
Registered
Joined
·
34 Posts
Discussion Starter #56
When you have come to the bottom of the barrel re logical solutions, then anything is worth a go! Only issue we have had with the pick-up-sensor has been a loose wire that we fixed by soldering.

Also worth mentioning is that we have tried after-market stators. Not been a successful solution for us. So when we have stator issues we replace them with OEM ones. The stators have been one of the main concern on the KTM's for us. I did a re-wind of one for a 85sx a few years ago. Took all night. Main problem was to get the old burnt one off as they are covered with some rock hard stuff that I ended up filing off to be able to rewind the bobbins.
Yea me to the stator is oem
 

·
Super Moderator
Joined
·
1,753 Posts
Try this: Put your multimeter to OHM, connect it across the pick-up-sensor (in the connector plug). You need the meter set on lowest setting of OHM. Take out the spark plug (so there is no compression), turn the engine from the rotor slowly and watch the OHM meter. (this is where the old meters with a dial were good). If you get a pulse you are OK. If not then either:
  • The pick up sensor is faulty
  • The connection of the pick-up-sensor is faulty
  • There is a break in the wiring of the pick-up-sensor
  • Your pick-up-sensor is too far away from the magneto (rotor)
  • The rotor (magneto) is faulty
 

·
Super Moderator
Joined
·
1,753 Posts
And while my mind is on this issue... also make sure that the pick-up-sensors solder connections/uncovered wires do NOT get in contact with the motor or any other metal (screws etc). Also check that all it's wires (both) are well insulated!
 

·
Registered
Joined
·
34 Posts
Discussion Starter #59
Try this: Put your multimeter to OHM, connect it across the pick-up-sensor (in the connector plug). You need the meter set on lowest setting of OHM. Take out the spark plug (so there is no compression), turn the engine from the rotor slowly and watch the OHM meter. (this is where the old meters with a dial were good). If you get a pulse you are OK. If not then either:
  • The pick up sensor is faulty
  • The connection of the pick-up-sensor is faulty
  • There is a break in the wiring of the pick-up-sensor
  • Your pick-up-sensor is too far away from the magneto (rotor)
  • The rotor (magneto) is faulty
Just tried it ohms read 98 when cranking when to 328 so its pulsing
 

·
Super Moderator
Joined
·
1,753 Posts
Just tried it ohms read 98 when cranking when to 328 so its pulsing
As we have had 2 same/similar bikes since 65cc I have always been able to fault find by swapping parts. But that might not be an option for you.

In one of your early posts you told us that the CDI from your 200cc did not give spark in this bike either (I still have not been able to establish what bike we are working on?) What is your bike? We know it is a 2008 XC-W. But not the cc's.

Does your 200 bike work well? If so, test the faulty bikes CDI in that one (only to see if there is spark!) Do NOT try to run the bike!!!
 
41 - 60 of 69 Posts
Top