82 Seca was running and now wont fire

[nedj10]

Hello everyone.

My seca will not fire. I took the headlight out and noticed the previous owner had shorted the kill switch hot off the brown wire coming off the Key-Switch. I broke the short and the kill switch works, but the bike wont fire, I put the short back and the bike still will not fire. I replaced the battery made sure its fully charged, and still no fire I put a voltage meter on the rectifier, and the CDI box, both have 12.7 or so volts in but no spark is coming out of the spark plug wires.

Not sure what to check next, I havn't checked the coils yet as I still havn't go the tank off. Is there something simple?

I have checked every wire, every connection and every ground wire I can find and every thing seems to be as expected.

Is there a method for debugging the voltage coming out of the ignition to the coil?

All of this of course was in my effort to determine why my gauge lights do not work and they still don't work.

thanks

Ned Williams

[nedj10]

Almost forgot,

I checked the spark with a timing light on each spark plug wire, no flash from the light when trying the starter

thanks

Ned

[JimR]

Hello everyone.

My seca will not fire. I took the headlight out and noticed the previous owner had shorted the kill switch hot off the brown wire coming off the Key-Switch. I broke the short and the kill switch works, but the bike wont fire, I put the short back and the bike still will not fire. I replaced the battery made sure its fully charged, and still no fire I put a voltage meter on the rectifier, and the CDI box, both have 12.7 or so volts in but no spark is coming out of the spark plug wires.

Not sure what to check next, I havn't checked the coils yet as I still havn't go the tank off. Is there something simple?

I have checked every wire, every connection and every ground wire I can find and every thing seems to be as expected.

Is there a method for debugging the voltage coming out of the ignition to the coil?

All of this of course was in my effort to determine why my gauge lights do not work and they still don't work.

thanks

Ned Williams

Hi Ned,

I guess you have copulated up but can you explain the short/misconnection between the main switch & kill switch as if either are connected together you will not get a spark, and how did you work out the kill switch worked without a spark somewhere ? Perhaps some good old fault finding is in order.

I guess the bike to be a DOHC XS400 if not disregard the post.

1) Check the pickup coil resistance

2) Check the readouts for each wire from the TCI/CDI unit from the manual

3) Insure the plug caps have not gone O/S

4) Check the saftey switches & wiring are in good order

Without more info it will be difficult to help you

Regards Jim

[nedj10]

Thanks Jim,

the short on the kill switch was discovered when I got the bike running and noted that no matter which position it was in, the bike would fire.

Upon further examination I found someone had run a jumper wire from the red-with white stripe-wire that makes the loop of kill switch, thus the switch always appeared on or was shorted hot.

I worked out that it work before as I had the bike running when the short was left in place, when I removed the short that is brought the kill switch back into the circuit the bike would crank but no spark was getting out from the coils to the wires. Replacing the short, If found the same condition now existed a bike that would crank but would not fire.

I will try to get the tank off tonight and check the voltage/impedence at the coils, what do you mean by safety switch?

And yes this is a DOHC 1982 xs400 Seca apologies for the lack of clarification earlier.

thanks,

Ned Williams

Hi Ned,

I guess you have copulated up but can you explain the short/misconnection between the main switch & kill switch as if either are connected together you will not get a spark, and how did you work out the kill switch worked without a spark somewhere ? Perhaps some good old fault finding is in order.

I guess the bike to be a DOHC XS400 if not disregard the post.

1) Check the pickup coil resistance

2) Check the readouts for each wire from the TCI/CDI unit from the manual

3) Insure the plug caps have not gone O/S

4) Check the saftey switches & wiring are in good order

Without more info it will be difficult to help you

Regards Jim

[nedj10]

She's back and running like a champ.

not sure exactly WHICH option fixed the problem but here is what I did today.

1)pulled the tank,(wow easier than I thought it would be)

2)checked the wiring I could under it pulled the two transistor looking device directly under the rear tank bolt, reseated.

3)remarked at how IMPOSSIBLE actually getting to the coils must be.

4) with the tank off I was able to actually detect spark with the timing light, apparently the extra insulation on the wires was blocking it(on the part of the wire that travels over the head)

5)pulled the plugs..sure enough they were quite fouled looking. being that it was 10 pm and the nearest parts store still open is 20 miles away I took sand paper and electrical connection cleaner to them.

6)re-installed them, the bike started

7) taped up the wiring with the kill switch still active i.e. the previously detected short-jumper wire I left the wire in existence with the connection broken and capped off(trying not to push my luck here)

8) Put the headlight back on, and took her for a test spin

still don't have my gauge lights and I managed to break one of the two tabs off on one side of the fuse that feeds the headlight but it still connected good enough for a quick 1 mile test run.

and yes I will replace those plugs as soon as I can get to the parts store .

tommorrows job will be to get her a tag.

thanks for the help

Ned

[JimR]

Thanks Jim,

the short on the kill switch was discovered when I got the bike running and noted that no matter which position it was in, the bike would fire.

Upon further examination I found someone had run a jumper wire from the red-with white stripe-wire that makes the loop of kill switch, thus the switch always appeared on or was shorted hot.

I worked out that it work before as I had the bike running when the short was left in place, when I removed the short that is brought the kill switch back into the circuit the bike would crank but no spark was getting out from the coils to the wires. Replacing the short, If found the same condition now existed a bike that would crank but would not fire.

I will try to get the tank off tonight and check the voltage/impedence at the coils, what do you mean by safety switch?

And yes this is a DOHC 1982 xs400 Seca apologies for the lack of clarification earlier.

thanks,

Ned Williams

Hi Ned

I guess we have the start of 2 different languages (heaven help English speakers in the future !) I dont quite work out what 'shorted hot' means .... is this the fuse blows or not ? "loop of the kill switch" what does that mean not sure but perhaps it means the wires from the r/h switch are connected together and loops within its functions ... i.e the starter motor running the whole time & and the ignition is grounded/earthed the whole time ?

sorry I cannot be more help until I manage to translate what you are saying.

Regards Jim

[JimR]

She's back and running like a champ.

not sure exactly WHICH option fixed the problem but here is what I did today.

1)pulled the tank,(wow easier than I thought it would be)

2)checked the wiring I could under it pulled the two transistor looking device directly under the rear tank bolt, reseated.

3)remarked at how IMPOSSIBLE actually getting to the coils must be.

4) with the tank off I was able to actually detect spark with the timing light, apparently the extra insulation on the wires was blocking it(on the part of the wire that travels over the head)

5)pulled the plugs..sure enough they were quite fouled looking. being that it was 10 pm and the nearest parts store still open is 20 miles away I took sand paper and electrical connection cleaner to them.

6)re-installed them, the bike started

7) taped up the wiring with the kill switch still active i.e. the previously detected short-jumper wire I left the wire in existence with the connection broken and capped off(trying not to push my luck here)

8) Put the headlight back on, and took her for a test spin

still don't have my gauge lights and I managed to break one of the two tabs off on one side of the fuse that feeds the headlight but it still connected good enough for a quick 1 mile test run.

and yes I will replace those plugs as soon as I can get to the parts store .

tommorrows job will be to get her a tag.

thanks for the help

Ned

Hi Ned,

I guess it was not electrical then and the problem lied with some duff plugs. Can you tell me which tag you need (or is this an english thing) and the tag you require is the registration of the bike ?

Regards Jim

[drewpy]

I thought Tag was a game

[JimR]

I thought Tag was a game

hmm I guess so but my other ½'s Tag cost loadsa money and doesn't even tick, you would think a 4 figure watch would have a tick tock sound .... even if run by a battery !

Regards Jim

[nedj10]

hmm I guess so but my other ½'s Tag cost loadsa money and doesn't even tick, you would think a 4 figure watch would have a tick tock sound .... even if run by a battery !

Regards Jim

Hi Jim,

Shorted hot means the circuit was shorted to always be hot, the previous owner ran a jumper wire from the key switch brown (12V positive wire) to the return wire of the kill switch on the wiring harness as to make the bike think the kill switch was always on.

also the Tag is the License plate tag not a technical problem, a beaurocratic one not a problem anyone can help with just an excuse to hand the government more tax money

thanks

Ned Williams

[JimR]

Hi Jim,

Shorted hot means the circuit was shorted to always be hot, the previous owner ran a jumper wire from the key switch brown (12V positive wire) to the return wire of the kill switch on the wiring harness as to make the bike think the kill switch was always on.

also the Tag is the License plate tag not a technical problem, a beaurocratic one not a problem anyone can help with just an excuse to hand the government more tax money

thanks

Ned Williams

Hi Ned,

with it now .. 'in english' you could say 'always live' but I would guess an on/off switch could be breached by jumping the connections in the switch rather than attacking the loom/harness. As the Switch just earths out the brown I guess the previous owner had a track to earth on the positive side of the switch (and/or no earth to the handle bar, dependant on which way the switch failed) and just made a bad repair/fix rather than looking at the correct answer (perhaps a new r/h switch ?) and preserve the loom.. but I now now what a short hot means !

So could you explain the tag thing and why u need to pay if you have the correct documents on hand?

Regards Jim

[YamaHead]

So could you explain the tag thing and why u need to pay if you have the correct documents on hand?

Regards Jim

The TAG is a year sticker applied to your license plate.....proof of registration that's been paid......every 2 years here in Oregon.

[JimR]

The TAG is a year sticker applied to your license plate.....proof of registration that's been paid......every 2 years here in Oregon.

Hi,

OIC like our 12 month tax disc the registration thing was foxing me ...as here registration is seperate issue to the taxation, to a degree. It could be argued as you pay the DVLA (Driver & Vehicle License Authority) the fee for the disc, the people in charge of registration also. but you can change the title (registration) without cost (with the correct documents)... so we could say you say TAG we say TAX, I guess does sound a bit better than TAX, but the DVLA describe it as 'Road Fund Licence' !

Do you require a mandatory roadworthiness test also ? In the UK you need one for a bike 3 years old or older renewable every year, without the certificate a Tax disc/Tag will not be issued.

Regards Jim