Pickup Coil Connector

[1200fan]

Hi all,

As part of my Vmax's aim to drive me insane with numerous problems, it is now not starting. It turns over strongly no problem, but wont catch. There is definitely fuel and the coils are fine.

I've tested the pickup coil and the resistance is fine (103.5 ohms with single orange/black wiring) but there is nothing from the male connector from the loom that goes to the pickup coil connector.

I'm being thick I know, but just to check should there be any voltage/resistance at the loom connector for the coil with the ignition on?

Cheers all...

 

[sdt354]

If I'm understanding you right your checking a pick up coil? If so, you'd unplug it and probe the plug pins to get a resitance reading. The key position won't matter. The directions in the Yamaha shop manual are wrong, as to which wires to check. There is a thread on this forum that addresses this issue. Mark-Maleko brought attention to this a while back. http://www.vmaxforum.net/showthread.php?t=8919&highlight=check+pick

I think we've covered it all, just about. The thread/post search is invaluable.

Steve-o

 

[unruhly]

My past experiences with working on motorcycles would say 'No, there is no voltage supplied to the pickup coil'. Rather, the pickup coil produces a very small AC voltage pulse each time the magnet passes the coil as the engine turns. This pulse is what activates the spark to the spark plug.

Having said that, I am a noob on the Vmax and it's possible this may not be the case.

 

[davesax36]

Is your battery fully charged? It doesn't take much of a drop to make these things not want to start.

 

[jfeagins]

I went through a couple agonizing YEARS in which I would meticulously maintain good battery charge (small OEM battery) overnight, yet come time to go to work first thing in the morning, the bike would crank & crank w/o starting until the battery began to fizzle. I'd put it back on the maintainer until after work, then in the afternoon upon getting home, the bike would fire 1st thing. ONLY diff was the heat of the day may have made the motor spin a bit easier, and therefore require less amperage to turn over. ???

FOR ME, the fix was going through my entire charging system and getting a better charge rate. Also at the same time, I suppose I cleaned up a bunch of ground connections from the battery to frame, etc. I, also at the same time, did the battery box mod which allowed me to install the larger battery. I've never experienced that cold-start failure condition since.

 

[1200fan]

Thanks everyone :eusa_dance:

Cheers Unruhly, that was what I needed to hear, if there's not meant to be current going to the pickup coil then all is good and I can look elsewhere for the problem.

My battery has been on the Optimate for the last couple of weeks so that's ok. I also did some mods to the wiring last year for the charging system, making a new ignition wire to get rid of the "crimp" completely.

My big worry now is if the CDI has gone. I know one of the CDI connectors supplies the ignition advance unit as well as the pickup coil so I could test the advance unit wires to see if they work ok also?

 

[jfeagins]

What is your voltage dropping to during starter spin?

What kind of spark, strong, weak, or not at all, do you get while cranking?

 

[1200fan]

Hi sorry for the wait getting back on here.

Cheers for the tip jfeagins. I've checked the battery voltage.

After connecting the battery back up there was approx 12.6V just hooked up. With ignition on and spinning the starter for a few seconds I get 10.7 - 10.8V. With ignition back off, the battery voltage now reads 12.4 - 12.5V. What do you reckon?

I will check the spark on the plugs doing the grounding on the engine case trick when I'm next with the bike.

Thanks again for your help again everyone, its much appreciated!

 

[unruhly]

Yeah, what jfeagins said:

What voltage do you have 'while' cranking? It's not clear if your 10.7 - 10.8 volts you mention is while cranking, or just after cranking. If it's after cranking, and it's dropped that much with the ingition ON, then I suspect a shorted cell in the battery.

It's possible, you're not getting enough voltage to the coil at the same time the starter is pulling amps. Electrons take the path of least resistance, so if you're battery is weak or has a shorted cell, everything is going to go to the starter motor leaving insufficient current/voltage to induce the coil and you'll not get enough spark, if any to start the engine.

 

[1200fan]

Cheers again Unrhuly. The 10.8 - 10.8V is whilst cranking the motor. Afterwards the voltage is 12.46V.

 

[1200fan]

Hi again all, sorry to dig up an old thread. I'd replaced the coils with COPS from a GSXR and made the harnesses for these with the resistors. Still no joy in getting the bike to start

I'm currently testing to see if the CDI box has broken by seeing if there is a voltage in the connectors going to the CDI. So far these connectors are working fine (red/black wire and all the coil wires are showing 12V) so it looks like a replacement one may be needed.

However before I can properly confirm this I need to check about the orange wire from the pickup coil going to the CDI connector. With the ignition on there is no voltage in this wire going to the CDI.

Is having no voltage in this wire normal, i.e there is only a signal going to the CDI when the bike is running and the pickup coil is sending the signal to the CDI?

If this is the case then it looks like the CDI has gone. If not and there is meant to be a 12V supply going to the CDI from the orange wire then a new pickup coil would be needed.

Cheers again everyone

 

[1200fan]

Just re-read Unruhly's post about the battery voltages, and realised I need to check the voltage with the ignition on just after cranking - I had tested with the ignition off. Argh! My apologies for the misunderstanding Unruhly.

With the ignition staying on after cranking the engine, what kind of voltage would there need to be for it to be a healthy battery?

Cheers again all

 

[one2dmax]

Needs to stay over 10 volts! I just got done tearing a bike all the way apart including the harness for nothing but a bad battery!