early mag systems

[Bevel bob]

I have never managed to post a photo on the forum . but can send to a mobile or E.mail.

[Jordan]

I cant check the ignition timing as done in the manual with a battery and bulb across the points

Later Ducati singles were designed to be timed with a strobe light on a running engine.
It's a good system, if you can attach a suitable pointer or disc to the left end of your crankshaft.

[mrkprsn]

I time my ducs statically. Find TDC, advance it X degrees and add 28 to that. I've time two recently, a 1962 200GT (46-49 degrees total) and a 1966 Sebring (33-36 total).

[Jordan]

An advantage of the strobe method is that you can be more certain you get the timing you want at full advance, where maximum power is made.

[Bevel bob]

Wow, what a great little forum we have , so nice to share our issues. Although not a Ducati the mag system was used on the early Ducati bikes so any discussion here is really usefull to us. The Motobi 175 is in very beutifull decorative condition and a potential show winner ,but has a few mechanical problems that are going to take a while to fix. The layout looks similar to the Ducs but there are differences that make it a challenge. The ignition components (apart from the under tank coil) are all in the flywheel and to strobe will need the motor to be running and then dismantle the side cover and kickstart while still running. . Alternatively i could cut an access port in the casing and fit a rubber plug. The current issue is that i cant follow the static official Motobi book system with a timing light as for some strange reason both sides of the points are earthed ! . This cant be right but somehow the points are still managing to trigger the spark ,but i suspect that to cause this one component must be on the way out and will fail soon ?. The other serious issue is that the main primary drive gears are badly worn and produce a lot of noise. Getting some better gears is a big issue .Spares generally not in the UK.I have photos of the ignition if someone interested in a puzzle !. I have managed to shorten the centerstand ,and fix useless brakes and clutch drag and adapt control levers so some progress. Engine terribly dirty inside and i suspect missing rings and worn carb parts made a very rich mixture.