Scooterotica

I am a self confessed numpty when it comes to electrics- its a black art to me and I just don't understand it. Perhaps someone can point me in the right direction.

I have a 12v electronic system on one of my scooters which is playing up occaisionally.

It tends to misfire after a few miles and the basic digital rev counter I have fitted (wire wound round HT lead) drops to zero although the engine still runs just.

After a while it clears and is OK thereafter ( I did think it was a duff fuel tap but the digital rev counter would imply its not)

Anyone like to guese at the most likely area which could be faulty before I simply replace piece by piece?

thanks in anticipation as always

Chris

I have a very similar sounding problem, I've gone through cleaning the carb etc changed the plug, checked for a loose earth, made sure the H.T lead and plug cap are ok and checked inside the headstock to see if anything is out of sorts. No luck, i'm now looking into the regulator and cdi unit. The only problem is i'm on a Varitronic system so cant use the standard units they have (so i'm told) I have a BGM regulator on the way and hope it's compatible with the Vario. The regulator is the cheaper of the 2 units that's why i'm trying there first. I'll let you know how I get on when it arrives.

thanks- that would be helpful.

Nothing worse than intermittant electrical faults IMO

Chris

I'm guessing you have the all in one CDI and ignition coil, if so can you borrow a spare to try many people carry one on the scoot just in case.

The Ducati ones can be as much as £3o but the cheap copies are less than a tenner, they come with an HT lead. personally I'd get a cheap one and if it turns out not to be the problem you have spare to keep on the scoot for the future.

Allein wrote:I'm guessing you have the all in one CDI and ignition coil, if so can you borrow a spare to try many people carry one on the scoot just in case.

The Ducati ones can be as much as £3o but the cheap copies are less than a tenner, they come with an HT lead. personally I'd get a cheap one and if it turns out not to be the problem you have spare to keep on the scoot for the future.

Absolutely agree with that, it isn't possible to test a CDI so substituting another one is the only way of proving/disproving a problem with them. That said, CDI's tend to fail completely in my experience rather than intermittently. If you can get hold of a cheap multi-meter (maplin or ebay for less than a tenner) you could check the resistance of the Low Tension (LT) Coil which should be around 450 ohms and the pickup which should be around 95 ohms. Have a check of all connections especially the earth, you can use the meter to test that too looking for as close to zero ohms as possible.

If all checks out ok it could still be a fault on the stator. I have had a few LT coils fail where the wire has broken but only separated when it got hot as the engine warmed up. Another common cause of intermittent faults is the riveted earth tag on the stator which are often loose and need peening over with a hammer and dolly to tighten. Before you go too far though, the first thing to do in ANY ignition fault is to disconnect the green wire on the CDI that goes to the ignition switch, you will need to stop the engine by stalling it but if the fault is still there it will at least eliminate any issues with the ignition switch or loom wiring.

thackers wrote:..... i'm now looking into the regulator and cdi unit. The only problem is i'm on a Varitronic system so cant use the standard units they have (so i'm told) I have a BGM regulator on the way and hope it's compatible with the Vario. The regulator is the cheaper of the 2 units that's why i'm trying there first. I'll let you know how I get on when it arrives.

I don't have any direct experience of the Varitronic system but I DO know that the regulator has nothing whatsoever to do with the ignition side of things. As with the Indian setup, the regulator controls the output for the lighting only. Different circuits using different coils.

thanks to everyone so far and also Daggs that PM'd me.

Went over the whole system today- simply making sure all connections were secure and clean (one of the spade connecters on the CDI was quite badly corroded!!). Checked all earths and wires for shorts- nothing untoward.

Took it for a blast and again it cut out at high RPM, BUT, my cheap and cheerful rev counter was still showing "normal" revs. Throttled off, engine picks up and away we go.

Then checked fuel tap.........................................dribble; dribble.

Changed tap. Another blast and no problem.

So- 2 faults? Fuel tap and something electrical?

Going to follow the suggestion of getting a spare CDI just in case.

Thanks Gents.

Chris

I agree that CDIs normally just die but coild can be intermittent and on the one you are using the coil is integral.

I was running one of the lucus coils with a separate CDI but rewired it all in the last rebuild to one of the more common one box units. I used a cheap £10 Ebay special for ages until recently I had a breakdown which was clearly electrical, I was near my local scooter shop so someone popped over an got me a proper Ducati one.

It didn't turn out to be the problem ( bloody cutout switch) but I've now fitted the Ducati item and keep the other on-board as a spare.