Puzzled.

[MaxMidnight]

Short answer is that I don't know but I suspect any difference, if any, will be marginal.

 

[Limeyrider]

Hey 02GF74,
My son bought a new cap ...using a Yamaha part number ... that cap is 5,000 ohm, the other caps ...originals ??...are 10,000ohm.
I am getting a battery voltage of 12.8v, and a " fairly " consistent circuit voltage of 10 v / 10.8 v ?... I stuck a short piece of H/T lead into the rear coils and measured the voltage by attaching my multi tester to the bare wire .. I got 10.8 volts, same on the left hand rear coil. I held the length of H/T wire close to the cylinder head and turned the engine of on the switch ... no sparking between the wire and the head. That is my test on the old Brit bikes that I have ... maybe the Oriental stuff is different ! ??.
The ignition switch is receiving 12.8 volts, and output to the brown wire is 11.9 volts ..... the contacts look brand new, I don't know why there would be a voltage drop ??. I have measured voltage at the R/W indicated in the manual .... 10 .7 volts .... front and rear coils. I'm stumped, don't know where to try now. I'd hate to have my son buy replacement coils if the answer lies elsewhere.

 

[Fire-medic]

Well, what is the bottom-line? To me, it would be, "how's it operating?"

If the bike is starting promptly, isn't hesitating, and pulls to redline, and the battery is accepting and holding a charge, I'd just ride it.

You might consider COP's, to see if there is any difference. COP's is a 'whole-nother issue in itself. However, many members have used COP's with success, but you should be forewarned that the 'early' model ignitions with the two pick-up coils (1985-'89) have been reported to have failed because of not having a balanced load the same as the OEM ignition presents to the ignition control unit (ICU). The issue of a failed ICU while using COP's seems to be less of an issue for those with later model ignitions (1990-'07). I use a COP's system, but it has a resistor for each COP 'stick' to provide a balanced load. I bought the set from one of our members, but he isn't making them anymore. I believe Sean Morley can supply you with the M-F plugs, and possibly the 'sticks,' but the last I read, you will have to 'roll your own.' Contact Sean for what he can do for you [email protected]

There is an ebay seller who is providing them, (COP's for a VMax) but I don't know that he includes resistors.

The advantage to COP's is that if one goes bad, it is a quick, simple replacement, plug & play assuming you are using OEM connectors. There are many threads on the building of COP's, the use of COP's, and a few about problems after installing COP's. My advice is to read the threads, and decide if this is something you wish to attempt.

 

[02GF74]

I don't expect the lower cap resistance to cause issues so let's put that to one side.


BTW you did reconnect the ignition /turn signal relay?

The laws of physics are consistent regardless of whether you are in Birmingham, Wisconsin or Hamamatsu.


Old British bikes were overseen by Lucas, the Prince of Darkness so that's one thing that isn't going to plague you.


Ignition, res wire power in, brown wire power out.


If you measure almost 1 v difference then there's gotta be a problem. (I assume the negative (black) lead to your meter is connected to the same point, namely the battery negative terminal for all your measurements. Either the wire connectors - presumably spade type, are not making good contact, the wire to spade crimps are bad or the switch contacts are bad.


Note sometimes the spades loosen, squeeze the female spades a little bit using a small pair of pliers to reduce the gap so they grip better.


If you unplug the brown wire, what is voltage on the output switch tag?


You could try bypassing the ignition switch by connecting brown to red (make up a short cable with the male spades) and measure voltage at the coils.

BTW you should be measuring voltage at the input to the coils. I am not sure measuring voltage at the coil HT lead is meaningful.

If you fit a spark plug to a lead, with the plug resting on the cylinder head, do you get a spark when cranking? (helps to do this when it's getting dark to better see the spark. (you can remove all plugs so the engine turns quicker)

 

[Limeyrider]

Well, what is the bottom-line? To me, it would be, "how's it operating?"

If the bike is starting promptly, isn't hesitating, and pulls to redline, and the battery is accepting and holding a charge, I'd just ride it.

You might consider COP's, to see if there is any difference. COP's is a 'whole-nother issue in itself. However, many members have used COP's with success, but you should be forewarned that the 'early' model ignitions with the two pick-up coils (1985-'89) have been reported to have failed because of not having a balanced load the same as the OEM ignition presents to the ignition control unit (ICU). The issue of a failed ICU while using COP's seems to be less of an issue for those with later model ignitions (1990-'07). I use a COP's system, but it has a resistor for each COP 'stick' to provide a balanced load. I bought the set from one of our members, but he isn't making them anymore. I believe Sean Morley can supply you with the M-F plugs, and possibly the 'sticks,' but the last I read, you will have to 'roll your own.' Contact Sean for what he can do for you [email protected]

There is an ebay seller who is providing them, (COP's for a VMax) but I don't know that he includes resistors.

The advantage to COP's is that if one goes bad, it is a quick, simple replacement, plug & play assuming you are using OEM connectors. There are many threads on the building of COP's, the use of COP's, and a few about problems after installing COP's. My advice is to read the threads, and decide if this is something you wish to attempt.

The simple answer is.... the bike is not operating, and , apparently, has not operated in quite some time ... the seller has a newer Kawasaki and he set the Yamaha aside some years ago. The bike does not start ... hence the discussion on no sparks ... or VERY weak spark from one coil .... so far. Not familiar with COP's ??. Before stepping into that option ...I would like to at least get some life into the bike as it is now.

I don't expect the lower cap resistance to cause issues so let's put that to one side.


BTW you did reconnect the ignition /turn signal relay?

The laws of physics are consistent regardless of whether you are in Birmingham, Wisconsin or Hamamatsu.


Old British bikes were overseen by Lucas, the Prince of Darkness so that's one thing that isn't going to plague you.


Ignition, res wire power in, brown wire power out.


If you measure almost 1 v difference then there's gotta be a problem. (I assume the negative (black) lead to your meter is connected to the same point, namely the battery negative terminal for all your measurements. Either the wire connectors - presumably spade type, are not making good contact, the wire to spade crimps are bad or the switch contacts are bad.


Note sometimes the spades loosen, squeeze the female spades a little bit using a small pair of pliers to reduce the gap so they grip better.


If you unplug the brown wire, what is voltage on the output switch tag?


You could try bypassing the ignition switch by connecting brown to red (make up a short cable with the male spades) and measure voltage at the coils.

BTW you should be measuring voltage at the input to the coils. I am not sure measuring voltage at the coil HT lead is meaningful.

If you fit a spark plug to a lead, with the plug resting on the cylinder head, do you get a spark when cranking? (helps to do this when it's getting dark to better see the spark. (you can remove all plugs so the engine turns quicker)

Well, what is the bottom-line? To me, it would be, "how's it operating?"

If the bike is starting promptly, isn't hesitating, and pulls to redline, and the battery is accepting and holding a charge, I'd just ride it.

You might consider COP's, to see if there is any difference. COP's is a 'whole-nother issue in itself. However, many members have used COP's with success, but you should be forewarned that the 'early' model ignitions with the two pick-up coils (1985-'89) have been reported to have failed because of not having a balanced load the same as the OEM ignition presents to the ignition control unit (ICU). The issue of a failed ICU while using COP's seems to be less of an issue for those with later model ignitions (1990-'07). I use a COP's system, but it has a resistor for each COP 'stick' to provide a balanced load. I bought the set from one of our members, but he isn't making them anymore. I believe Sean Morley can supply you with the M-F plugs, and possibly the 'sticks,' but the last I read, you will have to 'roll your own.' Contact Sean for what he can do for you [email protected]

There is an ebay seller who is providing them, (COP's for a VMax) but I don't know that he includes resistors.

The advantage to COP's is that if one goes bad, it is a quick, simple replacement, plug & play assuming you are using OEM connectors. There are many threads on the building of COP's, the use of COP's, and a few about problems after installing COP's. My advice is to read the threads, and decide if this is something you wish to attempt.

 

[02GF74]

Not familiar with COP's ??. Before stepping into that option ...I would like to at least get some life into the bike as it is now.

There are thousands of Vmax bikes running OEM ignition so I don't consider COPs are the magic bullet. If it won't run with coils, say because the ignition unit is toast, then COPs won't help.

Have you disconnected all the coils and measured primary and secondary resistance for each? The manual gives ohm values.

Also you are aware that the ignition lead is a push fit into the coil. The leads can corrode, Fixed by cutting off about 5mn so that clean wire is making contact with the pin I the coil, the grommet thing grips the lead and squeezes it into the coil for good contact. There was a post about this recently where the poster used his teeth to do this !!!!

None of this is rocket science, just needs patience to work through methodically as you are doing.

 

[Limeyrider]

I don't expect the lower cap resistance to cause issues so let's put that to one side.


BTW you did reconnect the ignition /turn signal relay?

The laws of physics are consistent regardless of whether you are in Birmingham, Wisconsin or Hamamatsu.


Old British bikes were overseen by Lucas, the Prince of Darkness so that's one thing that isn't going to plague you.


Ignition, res wire power in, brown wire power out.


If you measure almost 1 v difference then there's gotta be a problem. (I assume the negative (black) lead to your meter is connected to the same point, namely the battery negative terminal for all your measurements. Either the wire connectors - presumably spade type, are not making good contact, the wire to spade crimps are bad or the switch contacts are bad.


Note sometimes the spades loosen, squeeze the female spades a little bit using a small pair of pliers to reduce the gap so they grip better.


If you unplug the brown wire, what is voltage on the output switch tag?


You could try bypassing the ignition switch by connecting brown to red (make up a short cable with the male spades) and measure voltage at the coils.

BTW you should be measuring voltage at the input to the coils. I am not sure measuring voltage at the coil HT lead is meaningful.

If you fit a spark plug to a lead, with the plug resting on the cylinder head, do you get a spark when cranking? (helps to do this when it's getting dark to better see the spark. (you can remove all plugs so the engine turns quicker)

Yes, I did replace the ignition / turn signal relay.
Poor Joe Lucas ... gets hammered because the bean counters insisted on " cheaper" parts.
I have the black lead on my meter connected to the same ...polished ... battery negative connection.
I have cleaned the male/female connectors, I have not squeezed any connections ... that is a job for tomorrow, you say to " unplug the brown wire " ... from where ?, if you mean the ignition switch ... the red and brown wires are soldered in place, as is the blue wire, they have a long " pig tail " that has a three pin connector attached ....I cleaned those pins, and also the contacts in the switch ... the switch " looks " brand new .
To make up a jumper lead to bypass the switch I would need to unsolder the mentioned connections .
This whole issue started when I took out all of the plugs , connected the plugs to their respective H/T leads and laid them on the cylinder head , the engine spun over readily ... but no sparks at the plug gaps ( .033" ), I ran a separate earth wire from each plug hoping that that would help .... nope !.
I measured voltage at the connectors that feed the coils ... per the Yamaha manual .... between 8.4 volts and 9 volts.
Thank for your input .... I will go over everything again .... tighten connections etc.

 

[02GF74]

I've not looked at the ignition switch so expected the switch to have tags, it doesn't. It has a lead with a 3 pin plug.

No matter, you need to unplug the plug and measure resistance between red and brown wires, this should be next to zero.

A Google to find an example switch shows there are two screws at the back so it can be taken apart and cleaned if connectors are poor. There looks to a hole (drain hole for water getting in via the key slot?) , squirting some switch cleaner and working the key may help clean the contacts.

Brotton line is there should not be almost 1 v difference between red and brown leads.

 

[Limeyrider]

There are thousands of Vmax bikes running OEM ignition so I don't consider COPs are the magic bullet. If it won't run with coils, say because the ignition unit is toast, then COPs won't help.

Have you disconnected all the coils and measured primary and secondary resistance for each? The manual gives ohm values.

Also you are aware that the ignition lead is a push fit into the coil. The leads can corrode, Fixed by cutting off about 5mn so that clean wire is making contact with the pin I the coil, the grommet thing grips the lead and squeezes it into the coil for good contact. There was a post about this recently where the poster used his teeth to do this !!!!

None of this is rocket science, just needs patience to work through methodically as you are doing.

I had a length of new H/T cable left over, I pushed that onto the coil " spike " and tested for voltage at the opposite end = 10.4 volts. I have measured voltage

I don't expect the lower cap resistance to cause issues so let's put that to one side.


BTW you did reconnect the ignition /turn signal relay?

The laws of physics are consistent regardless of whether you are in Birmingham, Wisconsin or Hamamatsu.


Old British bikes were overseen by Lucas, the Prince of Darkness so that's one thing that isn't going to plague you.


Ignition, res wire power in, brown wire power out.


If you measure almost 1 v difference then there's gotta be a problem. (I assume the negative (black) lead to your meter is connected to the same point, namely the battery negative terminal for all your measurements. Either the wire connectors - presumably spade type, are not making good contact, the wire to spade crimps are bad or the switch contacts are bad.


Note sometimes the spades loosen, squeeze the female spades a little bit using a small pair of pliers to reduce the gap so they grip better.


If you unplug the brown wire, what is voltage on the output switch tag?


You could try bypassing the ignition switch by connecting brown to red (make up a short cable with the male spades) and measure voltage at the coils.

BTW you should be measuring voltage at the input to the coils. I am not sure measuring voltage at the coil HT lead is meaningful.

If you fit a spark plug to a lead, with the plug resting on the cylinder head, do you get a spark when cranking? (helps to do this when it's getting dark to better see the spark. (you can remove all plugs so the engine turns quicker)

 

[Limeyrider]

I've not looked at the ignition switch so expected the switch to have tags, it doesn't. It has a lead with a 3 pin plug.

No matter, you need to unplug the plug and measure resistance between red and brown wires, this should be next to zero.

A Google to find an example switch shows there are two screws at the back so it can be taken apart and cleaned if connectors are poor. There looks to a hole (drain hole for water getting in via the key slot?) , squirting some switch cleaner and working the key may help clean the contacts.

Brotton line is there should not be almost 1 v difference between red and brown leads.

I took the ignition switch apart and found that the innards are very clean, it looks brand new.
I need to correct some info that I posted previously .... checking voltage at the input to the coils ( R/W ) wire ...I measured 10.86 at coil #1, 10.05 at coil #3, 10.79 at coil # 2 , 10.77 at coil #4.

 

[02GF74]

I measured voltage at the connectors that feed the coils ... per the Yamaha manual .... between 8.4 volts and 9 volts.

I don't know what manual you are using but from the wiring diagram the red/white wire and voltage atthe coils should be smae as battery. Also from the service manual (there is link on this forum if you don;t have it).


I dson't understand why you are seeing nearly 1 volt drop across the ignition switch - it should be negligible.

As for measuring the voltage on the HT lead, again if you look at the wiring diagram, the HT coil is connected through the windings to the red/white wire, as it is open circuit, it should be close to the voltage on red/white wire - whcih is what you measure. Again, the question is why is the volrage on red/white so low?

 

[Limeyrider]

Yes, I did replace the ignition / turn signal relay.
Poor Joe Lucas ... gets hammered because the bean counters insisted on " cheaper" parts.
I have the black lead on my meter connected to the same ...polished ... battery negative connection.
I have cleaned the male/female connectors, I have not squeezed any connections ... that is a job for tomorrow, you say to " unplug the brown wire " ... from where ?, if you mean the ignition switch ... the red and brown wires are soldered in place, as is the blue wire, they have a long " pig tail " that has a three pin connector attached ....I cleaned those pins, and also the contacts in the switch ... the switch " looks " brand new .
To make up a jumper lead to bypass the switch I would need to unsolder the mentioned connections .
This whole issue started when I took out all of the plugs , connected the plugs to their respective H/T leads and laid them on the cylinder head , the engine spun over readily ... but no sparks at the plug gaps ( .033" ), I ran a separate earth wire from each plug hoping that that would help .... nope !.
I measured voltage at the connectors that feed the coils ... per the Yamaha manual .... between 8.4 volts and 9 volts.
Thank for your input .... I will go over everything again .... tighten connections etc.

I don't know what manual you are using but from the wiring diagram the red/white wire and voltage atthe coils should be smae as battery. Also from the service manual (there is link on this forum if you don;t have it).
View attachment 85565

I dson't understand why you are seeing nearly 1 volt drop across the ignition switch - it should be negligible.

As for measuring the voltage on the HT lead, again if you look at the wiring diagram, the HT coil is connected through the windings to the red/white wire, as it is open circuit, it should be close to the voltage on red/white wire - whcih is what you measure. Again, the question is why is the volrage on red/white so low?


View attachment 85566

I corrected the voltage measurements at the coil relays ... all four are at, or above 10 volts .... but still less than the battery voltage ... ???. I am using the same manual that shows " main and engine stop switches are turned on. Is the TCI unit the large flat box behind the steering head ?. I will check the resistance between Red and Brown wires at the ignition switch pigtail. As for why the voltage is so low .... beats me !.

 

[Fire-medic]

the TCI unit the large flat box behind the steering head ?

Yes

 

[Limeyrider]

Hey Fire-medic ..... thank you.

 

[02GF74]

Well, what is the bottom-line? To me, it would be, "how's it operating?"

We may be chasing a non issue. (my fault, sorry)

Curiosity got the better of me so I removed the fake tank and seat (2 screws) - it will let me charge the battery.

So voltages are below, my bike runs very well so I assume the voltages are OK - note when running they will be higher due to alternator charging.

Battery 12.30 v (ignition off), 11.61 v (on)
Fuse 11.00 V
Coil red/white 11.11 v

So there is a loss of 0.5v. (I'm slightly surprised it's as high as that)

BUT the voltage at the coil is just 0.3 v more than yours, although you have new battery as well as cleaning up the contacts. (it may be even less depending on the accuracy of our meters)

My suggestion would be to chase the spark and maybe return to the wiring at a later date should the bike not run well.

 

[MaxMidnight]

I tend to agree with Mr 02GF74 re the wiring but to satisfy curiosity you could measure their resistance to identify any high resistance which may be causing voltage drop. Also check continuity on all the other relevant cables to ensure all circuits can operate.

Did you replace or re-connect the the starter circuit cut off/ signal relay? As the motor turns over on the button (?) then that would suggest the relay is OK.

If you don't have a spark at any of the coils then it is unlikely that all coils have gone AWOL (assuming primary and secondary resistance are OK) so I'd think they are unlikely to be the issue.

Assuming you have continuity on all wires and are satisfied that the cut off relay is OK then that would leave the pick-up coils or ignition unit as candidates for non start

Is it all cylinders that have no spark or just one pair? If the former then that may suggest both the pick up coils are OK but if it were a pair that were affected then I'd look at the relevant p/u coil.

Best test for the ignition unit is substitution. If you can borrow a known OK unit that would at least rule that out as the cause.

 

[VMAXXIMUM]

If your not getting spark on all 4 I would check the kickstand cut off switch.

 

[Fire-medic]

If your not getting spark on all 4 I would check the kickstand cut off switch.

That could be an issue. I include CRC, WD40, or other spray lubricant on the switch brass shaft, and ensure that the inner spring is still with tension to push-out the shaft, on the spring tune-up.

 

[Limeyrider]

We may be chasing a non issue. (my fault, sorry)

Curiosity got the better of me so I removed the fake tank and seat (2 screws) - it will let me charge the battery.

So voltages are below, my bike runs very well so I assume the voltages are OK - note when running they will be higher due to alternator charging.

Battery 12.30 v (ignition off), 11.61 v (on)
Fuse 11.00 V
Coil red/white 11.11 v

So there is a loss of 0.5v. (I'm slightly surprised it's as high as that)

BUT the voltage at the coil is just 0.3 v more than yours, although you have new battery as well as cleaning up the contacts. (it may be even less depending on the accuracy of our meters)

My suggestion would be to chase the spark and maybe return to the wiring at a later date should the bike not run well.

Hey 02GF74 .... I am curiously relieved that your good running bike voltages are pretty close to my measurements ...maybe I'm close to finding the solution ! . Thanks for your help.

 

[Limeyrider]

I tend to agree with Mr 02GF74 re the wiring but to satisfy curiosity you could measure their resistance to identify any high resistance which may be causing voltage drop. Also check continuity on all the other relevant cables to ensure all circuits can operate.

Did you replace or re-connect the the starter circuit cut off/ signal relay? As the motor turns over on the button (?) then that would suggest the relay is OK.

If you don't have a spark at any of the coils then it is unlikely that all coils have gone AWOL (assuming primary and secondary resistance are OK) so I'd think they are unlikely to be the issue.

Assuming you have continuity on all wires and are satisfied that the cut off relay is OK then that would leave the pick-up coils or ignition unit as candidates for non start

Is it all cylinders that have no spark or just one pair? If the former then that may suggest both the pick up coils are OK but if it were a pair that were affected then I'd look at the relevant p/u coil.

Best test for the ignition unit is substitution. If you can borrow a known OK unit that would at least rule that out as the cause.

Hey MaxMidnight ..... I will go over the wiring and test resistance ...hopefully all ok !.
The starter circuit cut off / signal relay is connected ... if you remember from earlier postings ... there is a crackling sound inside the unit ... not consistent, but there, could that be a cause of loss of spark ?....may seem to be an obvious answer ... but I'm not familiar with units such as these.
There is a VERY weak spark on #3 H/T wire, nothing on #1 H/T wire, I have not detected a spark on #'s 2 & 4 H/T wires.
As far a s substitution of parts goes ... neither my son or I know of another VMax in our local area ....or anyone willing to " loan " a valuable part.
Thanks for your input and suggestions.