Slow cranking 900SS

[clarks41]

My 1995 900SS of 3 weeks now, cranks fairly well when it cold, but if I shut it off after a 20 minute ride, it will crank very slow when I try to restart it. The next day when it's cold again, it will crank normally. I've tried another battery but it did the same thing. Any advice ? Thanks

[shoeman1952]

just got a 900 carb'd ss, PO said it cranked slow all the time even w/fresh battery. found the battery ground wire connection lug on frame needed to be sanded free of paint. sanded all pos/neg wire ends and lugs, installed battery tender and no more slow cranking. you will also find a frame-to-engine wire behind the rear brake m/c, do that one too. there is a "cable upgrade kit" that some folks like, but try sanding first.

just for curiosity, i'd check the charging voltage a various rpms.
bobp

[El Gladiateur]

You can find the "cable upgrade kit" at Ducati Parts by Desmo Times - The Home of DIY Ducati Maintenance.

For the charging voltage check, Shoeman is right: It'll allow you to check your regulator.

Stick a voltmeter on the battery. Start your engine. Let it warm, then rev it up to 4500/5000 rpms. Voltage must follow RPM's. If it doesn't, your regularor is K.O. If you read more than 15,5 /16 volts....the regulator is also good for the bin.

In the case your regualtor is fried, the electrex is cheaper than oem and seems to be reliable (Electrex Systems), the ref is RR51.
RR51 - regulator rectifierregulator/rectifierDUCATICAGIVALAVERDA350SS400SS600SS750SS90 0SS500 PANTAH600750900 MONSTER748750F1

To conclude, check your Alternator/Regulator yellow wiring, especially the crappy white connector. This bullshit fries most of the time. Send it in the bin or at Guantanamo and solder wires.

[Desmomaniac]

corrosion is usually a big culprit to poor starts and general electrical no workie, check all connections including grounds. dielectric grease helps keep connections clean of oxidation. moisture sometimes collects in the rubber boots covering connections and can cause poor contact; the starter is a bad one for this.

also the the old coils sucked... swapping over to the Dynacoils made a huge difference in better starting and low rpm stumbling after installing FCR's and lightened flywheel.