Scooterotica

At a loss........mate's TS1 won't start ...we have changed the stator and flywheel and CDI unit and although we have a spark ..still not starting. Not strobed it yet but I have the 'white' line from the pick up box in line with the lines on the flywheel at the firing point so should be ok.

Correct me if I'm wrong but wires from the stator all go to the blue CDI unit and the yellow to the rectifier with the 'green' from the ignition onto the lowest connecting point on the CDI (below the green connection from the stator) so all should be well.

Having considered the ignition side of things, Must confess now at a loss, could it be mechanical (although compression seems ok) ? Any ideas would be appreciated ?

Thanks

Is it getting fuel, plug wet?

Yes plug gets wet and on looking at carb seems petrol is getting through. It did start earlier tonight but then died soon after ??

The white lines on the pick up and, more specifically, the marks in the flywheel window are only reliable on original Ducati electronic or the early Ducati AF ignition, anything else should be treated as suspect. Even on the AF I set it using the arrow on the flywheel and a timing disc and use the line as a confirmation.
That said I'd still only expect it to be out by 10 degrees either way.

Thanks Ross.

For some background I checked the original BGM stator that was on the bike with an Ohms meter (before dismantling) and found the values in line with Stickys book (eg....0.0 (less than the 0.1), 110 (red) and 505 (green)) all within tolerance so assumed the stator was ok. However, a few fellow scooterists said the meter is sometimes not a conclusive method allied to possible BGM stator issues with the parts so we ought to change that, so we changed it and the flywheel for an AF one (brand new from a mate using the mid-weight flywheel....) and set it up using the white line between the marks on the stator method. It did start initially and then died (as it had done with the old set up on the bike). The intention was to get her going and then strobe it up after the initial test, but never got that far of course.

On both occasions (old stator and flywheel and new stator and flywheel and new CDI) it appears we get the bike started initially for a few seconds then it dies, after which we just can't start it at all. I was thinking maybe wiring elsewhere on the loom as this isn't overly well run, but IF we have new stator with new Ducati CDI, different HT lead (as suspected original) and new H.T cap I thought we would have covered it being an electric problem.......?? and does the loom outside of that just therefore deal with the lights and ignition.

We also tried disconnecting the green ignition wire from the CDI but it makes no difference. We had a dodgy plug initially, but the latest plug does have a decent spark. I'm thinking the bike should now start and run.....from building my own bikes, albeit the timing will need proper setting up from the 'white line' method.

I was gonna change the carb next and try a few more plugs next. Must confess I'm stumped a little on this one ? It has a 30mm PHBH carb on rubber mount. I did wonder if fuel starvation (ie; starts initially and cuts out) might be the problem but stripped off carb bowl and seems to let in petrol and cut off ok....but gonna change just in case

I've built 2 engines myself recently from shell (Avanti and Dave Webster steel barrel GP (a real frusty beast) and they both run without issues from the initial build with the exception of the 'melting carb float' issues. Admittedly I'm not a TS man .........

What next guys >

Snapped ring?? I have had this feels like compression but wont start.

Air leak?

What's the history, did it just not start one morning or did it cut out doing "90" two up, up a hill ?
Reed petals might be worth looking at.

Have you bypassed the ignition switch green wire from loom to cdi ? Just in case faulty switch

Check / replace one thing at a time take it you have done plug , cap and lead ?

Thanks for replies.......in response. The bike was bought a short while ago and supposedly rebuilt on the mechanical side by a scooter shop, thus we have pursued the electric circuit as being a problem, but now convinced its not that. Therefore since he bought the bike it was stored in a mate's garage and he just used to pop round to get it. It started and run ok when we did about 10 miles a few Sunday's back and then after putting it back it has had the starting problem since.

It does have good compression, but as you say that's not conclusive to no issues in the barrel, so I will strip off the barrel and take a look. I must confess did find some shiny iron filings in the bottom of the carb bowl last night and he has a stainless steel tank .....so could this have done something (not sure if the tank might be issue as some say it is others say it's not and personally I know a chap who has run one for years without problems).

I will also check the reed petals as stated.

I have undone the green ignition wire and it still did the same thing. Cheers will update later, thanks all.....