Hello,

It seems as the coils are getting really low voltage on my Sport. Can anyone make a suggestion of the best fix for this? I've read about installing the relay, the ExactFit High Voltage Ignition Coils, can't find any info about Bauke's relay....

What would be my best option to solve this?

Thank you!

Hi,

the best way to go is not to start with any modification. Go through your wiring first, clean all connections and ground connections. Get the wiring diagram and check which way the power to the coils goes.
It`s probably like on the Paso where the power runs via the right handlebar and then the ignition switch before it gets to the coils. If the switches are not perfectly ok and clean this is where the voltage drop occurs.
When you`ve cleaned all this the voltage loss should be lower, but you will most likely not get totally rid of it as some is due to the quality and age of the whole wiring.

So step two would be adding a relay which is simple. Get a standard 12V relay with 4 contact pins.
1. Find a position to mount the relay
2. Disconnect the 12V feed from each coil (isolate one end), connect the remaining end to pin 86 of the relay
3. Make a new Y cable to connect the relay output (pin marked 87) to the two coils
4. connect one relay pin to ground (85)
5. run a cable from the battery (with an inline fuse) to the relay (30)
That`s it. If you`re not sure how to connect the cables to the relay; main power feed and main power output (hence battery and coils) are across each other as are the switching feed and ground.

Step three is optional and would be aftermarket coils. Minimum resistance 3 ohms so something like the green ones from Dynatek. The black 5 ohms version would work as well.
Making step three before step two doesn`t make sense as you won`t get the full output of the new coils. You might just end up with a similar output the original coils would have under ideal conditions...

G.

Once again the wisdom of G. is not to be trifled with. All he states is true.
Just one bit of divergence though. The stock coils are now 20 years old, and so are their leads. The high tension leads can not be changed out on these coils. That alone is a good reason to upgrade the coils.
I put on aftermarket coils and it certainly improved things. (starting, overall performance, etc) I just cleaned all the contacts, and have not yet gotten to the relay step, but its definitely on my list of upgrades.

But certainly getting good voltage to them is key whether you have old or new coils.
Of course a well charged battery helps matter too.

Cheers, Phil

Thank you! Will check everything before making any modifications. So was this a faulty setup from the begining? What exactly does the relay do?

The Ducati wiring system is overly optimistic. It does not take account for connection losses into the design. It assumes no connection losses, but of course there are some on a new bike, and a lot more on an older bike. The relay ensures that you are getting full battery voltage to your coils all the time. Since they are coils, the input voltage has a big affect on the output voltages. Its not a direct correlation, its logarithmic. if you are missing 1/3 of your voltage going into the coil (quite possible on some bikes) your output of your coils will be much less than 1/3 of the intended. Weak spark = hard to start, not smooth running, bad fuel economy, lower power, less responsive, and so on.

Search the posts and you will find some wonderfully detailed investigations into the voltage drops at connectors and the resulting voltage at the coils.

Cheers,
Phil

Furthermore as the coils get their current directly from the battery (via the relay) and the ignition switch then only activates the relay there`s less load on the switches which should grant them a longer life.

If you add a hidden switch i.e. to interrupt the ground connection to the relay you`d also have something like an immobilizer.

G.

You guys are amazing! Thank you very much!!

http://vimeo.com/28875293

Nice video by the way. I miss riding the SoCal backroads at sunset. I assume you are the rider. Are you also the pianist?

Cheers, Phil

The saga continues.....

I installed the relay mod and it didn't increase the voltage at the coils at all (which is at 2V!) I guess it is possible the bike runs at this voltage. What happens is that when at idle it's somewhat hesitant and at a quick twist of the throttle it looses power and stalls. When riding though, it pulls very strong and I was able to take it to 120 quite easily. I know now, that the faulty plugs are most likely caused by the low voltage at the coils....

The wiring is absolutely intact and I checked over the connections. While looking things over I started to measure the voltage to see where the drop might occur... It isn't on the positive side of the current but actually on the negatives which go to the coils. I traced the wiring back to the Digiplex and it looks as something happens inside of it which causes the ground (negative) that enters the unit to drop the voltage down so significantly when it exits the digiplex - quite confusing (?). When I check voltage of the positive wire going to the coil against the negative, it is 2V and if I test it against a solid ground it is 12V. The ground entering the Digiplex gives me a reading of 12V.

Like I said in my earlier posts this bike is a time capsule and nothing has been modified on it so what exactly might be going on? Is the a simple fix for this or should I look into a new Digiplex unit?

When I got the bike, the plugs installed were the Champion RA8HC and I switched them over to the RA6HC. This is somewhat confusing as well... The sticker on the inside of the fairing states RA8HC while the workshop manual and the owners manual state RA6YC. I know this was replaced by the newer HC but why the two different heat ranges??

Thank you, Phil.

I've done the carb cam modification and it did help but there's still something a little strange about this carb.... Firstly, when the bike is on a center stand it runs smoothly - I would say great - besides loosing power after a quick throttle twist. When the bike is on its kick stand it starts loosing power, the rpms drop. The strange thing I noticed today that when going downhill the bikes' rpms go up quite drastically by themselves and stay around 2000-3000 for around 30 seconds.... When going uphill, or rather even at a small incline, the motor starts loosing power and finally dies. This happens every time I take it out of the garage where the ground is level so bike runs fine, the moment i start rolling it back onto the driveway, putting the bike at a slight incline, it dies.
The build up of rpms while riding after releasing the throttle is very annoying and sometimes dangerous when going into turns. The plugs still become very fouled and the exhaust smells pretty rich. Could all this be that the carb is becoming flooded?

not enough fuel in the float chamber. Either the level is off or the fuel supply is weak.

Thanks. Will take the carb off soon and rebuild it. The fual pressure is at 3.5 psi.

Higgy, would this also cause the loss of power with the quick rev up?

It is one possibility. Check your float level and check valve. Check the flow through the fuel filter as well. A restricted fuel filter can cause the pump draw electrically to go way up causing all kinds of issues,even a burned up stator and poor coil output all of which can be the cause of poor performance.