GTS starter system weak areas?

[bobnorton]

Getting into deep waters now, everything seems to work and the starter is trying to turn the motor (using a car battery ) , Appart from the usual cleaning of contacts ,earths etc what is worth modifying?,I did not expect a lot of action with temps at freezing and a motor running GP50 monograde, I will switch to something lighter once it goes.

[Craig in France]

Apart from the usual cleaning of contacts, earths etc, what is worth modifying?

Not sure there's much to be modified as such, Bob. As you suggest, the main thing is to make sure there's as little energy loss as possible thru the system - and only afterwards think about any mods.*

So for starters (no pun intended ), you might like to check the condition of the brushes and the commutator in the starter motor. And also check the solenoid - good chance it's pretty corroded up. Stick a meter across the motor side and see what resistance you get.

I did not expect a lot of action with temps at freezing and a motor running GP50 monograde, I will switch to something lighter once it goes.

. Yep, there's your two biggest problems ...

* For example, fitting bigger starter motor cables rarely goes amiss - assuming you've got enuf space to get them in, that is.

[bobnorton]

Thanks Craig, Does the starter have to come off for a peek inside ?.I was hoping to use a lighter battery than the one that came off, but after i nearly melted my cheap jump leads its clear that cranking power is key.Would have been better if Ducati had fitted de-compression device as on the singles.

[Craig in France]

Does the starter have to come off for a peek inside ?

Yep, Bob .. Sorry!

I was hoping to use a lighter battery than the one that came off ..

Yes, you can get a much more powerful, but lighter, battery than what was available at the time. Buy a AGM battery with the highest rating of Cold Cranking Amps ("CCA") that you can find. Have a look at what Steve sells - obviously you can't buy from him 'cos of shipping, but you can get similar from Tanya Batteries in the UK. But don't go too physically small, 'cos then you'll end up having to pack the battery out to make sure it stays stable in the tray.

...after i nearly melted my cheap jump leads its clear that cranking power is key.

Ok that tells me something ...

If your jump leads got hot, that means you were pulling significant amount of power to turn the engine over. That suggests that, apart from the molasses masquerading as oil that you've got in the engine (remember, Ducati specified a synthetic 10/50 from as early as 1977), you've most likely got some unwelcome resistances somewhere - either mechanical or electrical. If the engine turns over easy enuf on the kick start, then you know its electrical ...

What you don't want to do is to just chuck loads more amps down the cables to 'get over' the problem. That's how stuff gets melted and/or fires start ...
I sense that stater motor may be coming out ... . What resistances do you get across the solenoid?

[bobnorton]

Hi Craig, I understand resistance to be (NO YOU CAN'T BUY ANOTHER BIKE!!), I think i will try a proper battery set up before i strip the starter, as you say it seems to want to draw the current so --If it not broke---.This bike is just like my 250 ,full of issues not understood by previous owners and made worse by their efforts.Another saga.

[wdietz186]

Keep in mind the electric foot was never that good to begin with,Think 75 Norton Commando but without the aftermarket backup.

[Craig in France]

Keep in mind the electric foot was never that good to begin with

Very true, Bill - it is a clunky, cumbersome thing . Not one of Fabio's better works . That said, when you stall the bike at the lights, it's very useful . I managed to get mine to work ok for that kind of situation, but not to fire the beast up from real cold ...

[bobnorton]

Bet it would work if one cylinder had a compression release like the 450's.ease it over comp on the Ks then it would have a big run up to work.

[wdietz186]

I alway thought just the weight of the thing on the kickstart lever would be a bigger help.But then again I'm a bit of a Luddite and have some experience with Italian electrical systems.

[ColinS]

The electric foot on my 900 GTS '77 works rather well, even when cold but then the gearing was changed from the original fitment. Mind you, my garage is heated to about 10 deg. C (to stop the lathe etc. from rusting).

Cheers

Colin

[ColinS]

But then, the starter on the recently acquired SSD doesn't always spin up and I've not looked into it yet.

Must find some time.

Colin

[Craig in France]

Don't delay, Colin. A failing starter can end up wrecking your sprag clutch = big(ger) bucks and bike 'No Go' ... >:|!!!

Craig, Prophet of Doom

[ColinS]

Hello Prophet of Doom,
The sprag on the SSD is new, or was new less than 200 miles ago but I don't know what the PO did with the starter motor. I guess I should have a squint at the brushes to start with and see where that takes me but the overall standard of the PO's restoration suggests that he would have checked that out. Mind you, the paint on the starter motor doesn't suggest recent attention.

Cheers

Colin

[jockduck]

Weak starters, My GTS electric start has always been great, hot or cold, plus it copes with high comp pistons too, I also have a Bitza Darmah with a GTS engine and its electric foot was awful no chance cold and only 50% chance hot. I discovered the problem by accident and now its fixed and it the e-start works great. The problem was misalignment between the starter motor bearing bush in the clutch cover and the bush in the starter cover(5 screw thingy), I made a support plate to hold the pinion shaft while the cover was off so that I could observe the operation and measure the starter motor speed. When I tried it spun the engine like a top. I removed the temp support plate and replaced the cover and we were back to sluggish non starting, removed the cover again(always very tight) and checked the bush in the cover and it was clear that a lot of pressure was being applied to the top of the bearing surface by the motor shaft, I cheated and used a small scraper to remove 2-3 thousands of an inch from the area of the bush showing pressure, reassembled and now all is good hot or cold starts every time.
The bike is a bitza as I said so the clutch cover and the starter cover probably were never a pair at the factory, The starter cover is remarkably located with three dowels and the starter motor shaft is very well supported compared to the pinion shaft which carries almost twice the torque, I can't believe Ducati line reamed the starter bushes in the two covers at the factory I suspect they relied on assembly clearances for alignment.
Jock

[rick65]

The excessive current draw could possibly be from the resistance of the cheap jumper leads, those things are usually crap with bad connections and cable that's to small.