Don't want these Ads? Why not sign up as a Trials Central Supporter.

caleb93

Gas Gas Ducati Ditigal Convert?

22 posts in this topic

I just bought a 04 Gas Gas 280 pro with the Ducati Ignition system, and on the third ride it just sputtered to a stop. I've done extensive testing and I believe that I have narrowed the problem to the very problematic regulator/rectifier. I can make the bike run if I unplug the regulator and jump the AC power from the stator over to the CDI unit/coil. (The regulator does this internally) The bike will run and produce anywhere from 30v AC at idle and upwards of 60v AC revved up. Due to the difficulty of locating a new regulator/ the high price tag/ the general unreliability of the regulator I would like to make something else that could be easier to work on and hopefully be more reliable. 

The question is does the AC power to the CDI unit/coil need to be regulated to a specific voltage (like 12v AC) or does it just take whatever voltage the stator throws at it? (like 30-60v+)

I was thinking of buying a 12v AC regulator like this https://trialssuperstore.com/products/voltage-level-regulator to bring the voltage down to 12v AC and then run a fan regulator like this https://trialssuperstore.com/products/fan-regulator-gasgas to run the dc fan. My understanding of the fan regulator is its a half wave rectifier with a smoothing capacitor. If I am thinking about this correctly I should be able to run lights off the regulated AC, the fan off the fan regulator, and hope the CDI unit works great with 12v AC. If this is the case then I could potentially cut out the expensive Ducati regulator and run modern, cheaper and readily available parts. 

Has anyone done something similar to this with any success and without changing the CDI or the Flywheel/stator to the kokusan type?

Thanks for reading though my thoughts and I appreciate any insight anyone may have!

Share this post


Link to post
Share on other sites

Don't want these Ads? Why not sign up as a Trials Central Supporter.

I'm no expert but believe all CDIs take power directly from the stator with no conditioning.  See the later model wiring diagram in the link below.  The AC frequency is quite high so you probably need an oscilloscope to get an accurate number but it could be more like 200 to 400 VAC.  The voltage regulator is just a voltage limiting device.  The fan regulator would be a rectifier.  Based on the wiring diagram for the newer model, your plan sounds feasible.  Do you have a diagram for your model?

 

http://www.trialscentral.com/forums/topic/61402-2013-txt-pro-wiring-diagram/

 

Share this post


Link to post
Share on other sites

The diagram for my model... 

I believe that you are correct about the oscilloscope, I didn't think about that. It makes more sense because it hit me once and it seemed like it hit much harder than 60v AC. I got the idea from the kokusan ignition close to my year which is very very similar. 

If the voltage in reality is actually that high for the CDI and because I only have one lead off the stator I don't believe that I can chop that voltage down to "12v" and still make the CDI happy. Who knows if the regulator can even handle that kind of voltage anyways. 

The other way I could see this working is rectifying the high voltage AC to high voltage DC and then chopping it down to a manageable 12v and hoping that doesn't draw the AC voltage down too low.

Share this post


Link to post
Share on other sites

It sounds to me as though you are simply using the lighting circuit to power the ignition now. tHAT WOULD INDICATE YOUR POWER COIL TO THE IGNITION  MAY HAVE DIED.

Separate coils on most bikes. They can be repaired/rewound. Hopefully before you burn up the cdi, cause I have no idea what voltage it is designed for, and it is the windings that matter.

Share this post


Link to post
Share on other sites

Look at the wiring diagram for the Ducati ignition that I posted above. There are three wires coming out of the stator, the green and white are both the AC pickup coil which supplies a pulse of AC to the CDI unit to tell it to spark. The third wire is the yellow that powers everything else with the other leg of the winding being grounded. The yellow wire goes straight up into the regulator rectifier and internally connects directly (the terminals are soldered together on the inside) to the little yellow wire that provides the AC for the CDI unit. 

They are separate coils on most bikes like in the wiring diagram that mcman posted above, but not on mine unfortunately as this would be far easier to sort out. Thanks for the idea

Share this post


Link to post
Share on other sites

Pickup coils normally just have one wire.  Does the green wire also produce voltage?  I'm used to seeing something more like the link below of a 1996 where green is power to CDI and red is pulse.

Are you jumping Yellow large to Yellow small?  The 2004 diagram does suggest that a regulated voltage is being supplied by the regulator.  If you really think the regulator is bad, you could try cutting it open to see what is between yellow large and yellow small. 

This picture does suggest one charging coil.

http://www.ebay.co.uk/itm/2004-GAS-GAS-TXT-PRO-280-DUCATI-STATOR-PLATE-/232490214622?hash=item36217f24de%3Ag%3AnZkAAOSwPfZZvPWH&nma=true&si=zKqaO9%2Frdh%2BGEBvLNxm8fGDXnMM%3D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

 

 

 

 

 

 

 

Share this post


Link to post
Share on other sites

I have checked for voltage between green and white and got around 1.5V AC, I have not checked for power to ground on either wires, I will do that. Both the green and the white go to the very small trigger coil so I don't believe it powers the CDI but I don't really know.

I jump big yellow to small yellow to make the bike run with the regulator unpluged. The two terminals are soldered together inside of the regulator (I have already cut it open and looked, looking for a burned out resistor as some people have said can be an issue but not on mine as far as I can see). 

I already purchased the AC voltage regulator I talked about in the first post and hopefully I get it today, but when I do I am going to wire it up and see if the CDI unit will still work and go from there. I will post back with results. As well as looking for power to ground from the trigger coil on both terminals.

Share this post


Link to post
Share on other sites

So I did get the 12V AC regulator today and hooked the yellow wire to the yellows on the bike and grounded the black. I started the bike and AC voltage was right about 15V (as my meter reads) and everything seemed fine until I tried to rev up the bike and it just refused to rev at all. Sounded like it was missing left and right. So I unplug it and it starts runs and revs great just like normal. So this tells me that the CDI unit is powered from the yellow wire coming out of the regulator and it wants either unregulated AC or a much higher voltage than 15. This makes sense to me because as the rpms increase compression goes up and it is harder to jump the gap on the plug so the extra voltage would be needed to fire the thing. 

So my original plan will not work it seems unless someone else has an idea. I do believe that the bike can be run this way the only problem is there is no fan so it could easily overheat.

Tomorrow I get a high voltage rectifier and a DC regulator so I will try to wire them in and see if I can get the fan to work and run about 12V DC.

I tested the leads coming from the trigger coil to ground and it seems the green is in common with ground, I never got any voltage out of it and the white wire has about the same as reading between the two wires (green and white) around 1.5V. They have 250 Ohms between the green and white which I believe is close to what it should be but i'm not 100%. Yellow to ground reads .7 Ohms. I have no idea if that is even close. 

Share this post


Link to post
Share on other sites

Based upon your description it seems you would need to split the one exhisting power source, possibly with a diode, and then regulate and rectify the one side only for light and fan which is required for DC fan motor operation.

 

Regulator  and rectifier are common  items to older Sherco and Beta for sure, Sanval 415 or summat for the reg., and all they do is shunt off excess to ground(earth).

Share this post


Link to post
Share on other sites

I tried this but it didn't work for me and I switched to Kokusan.

Whenever the spark went out it was always the regulator/rectifier box so I guess if you can find the right diode or whatever you can solder in a replacement.

Share this post


Link to post
Share on other sites

I agree with you copemech but I am having issues hooking up a full bridge rectifier without cutting out the spark. The way to hook up the rectifier would be to put one AC side on the yellow wire on the bike and the other AC side to the ground, I believe as the other leg of the stator is grounded. Then I should have DC outputs to hook to the fan. I have tried hooking up the rectifier the "wrong way" and lots of other ways with the same results, being as soon as the ground is hooked up the spark quits. I have been unable to get around this but I have tried using a diode as a half wave rectifier (input to yellow, output to fan) and this will make the fan work with some trashy DC but the voltage is unregulated and runs real high which will burn out the fan quickly. I tried today to put a DC to DC regulator (30-60v input, 12v output) after the diode and once the ground is hooked up no spark. 

I played today with resistors off the yellow wire to power my supposed DC circuit and I still couldn't make a spark with a full rectifier wired in but I only had 24 ohms of resistors. I'm getting more and I will try out higher resistances to see if the CDI circuit voltage stays high and if can cut down my DC circuit voltage.

I looked further into the trigger coil wires and it appears that the white wire is in common to ground. It reads a direct short between ground inside the CDI and to test if this is more or less normal I cut it, it produced no spark, then grounded the white wire to the frame and it started and ran fine being disconnected from the CDI.

sectionone I had read that thread and it is what lead to me taking my regulator apart in the first place to look for the problematic diode but mine didn't have one like the example in the picture. Switching to Kokusan is the right fix and I would like to do that but I have been unable to find any with the little looking I did.

Ill play some more with resistors once I get them in and post back with whatever I find.

Thanks for the replies

Share this post


Link to post
Share on other sites

are you in thre UK? Might try calling or email to Steve at Motoplat UK/ Bradford ignitions as he may shed some light. He has made a living figuring many of these type things out.

 

 

Share this post


Link to post
Share on other sites

I bought a complete Kokusan system from trialsbikebreakersuk ebay store for $370 in May 2016. Earlier that year they had another system they sold as a kit and around that time you could also piece together a complete system. Now they seem to have dried up but you could keep checking. You could get one here if he still has it.

 

I have three Ducati regulator/rectifier boxes that you can have for free. Also have the flywheel, 2 coils, 2 pickup coils and stator.

Share this post


Link to post
Share on other sites

No I am in Washington state but still talking to Steve would be a good idea. Once I run out of ideas I'll give him a call. 

That is a great site! I will keep checking them to see if anything comes up. I'll see if Jim still has his. 

I'll take your regulators if you just want to get rid of them, I don't know if I can make any good of them but I am not shy to try.

Share this post


Link to post
Share on other sites

too bad Jim got kicked off this site but he does post on ADV rider in the trials section so you could try posting your question there. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now