Sticky starter

The Cagiva era Morinis

Sticky starter

Postby clanger9 » 15 Dec 2019 13:29

When it's cold, the starter on my bike doesn't always engage properly. It presumably just needs cleaning/lubrication.

Is this an easy job on a Dart? The starter is on the front, which is different to what's shown in the blue service manual.
I'm not sure where the sprag clutch is and the Dart manual doesn't give many clues...
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Re: Sticky starter

Postby morini_tom » 15 Dec 2019 18:31

The starter motor itself on the dart down not normally give trouble.

It’s a sealed unit. They can be taken apart and cleaned but I generally regard them as zero maintenance.

The sprag clutch on the other hand does give trouble. If you are finding that the starter motor turns but not the engine, or it starts making funny noises then it’s almost certainly the Sprag.

The sprag clutch rubbers break up and if the starter is becoming unreliable then you absolutely should check it out as tiny bits of rubber floating in the oil are bad news!

It’s all under the cover at the front left hand side of the engine and can be stripped out easily in situ, although don’t do it on the side stand as you’ll lose an awful lot of oil, and also having the bike level on a paddock stand I find really helps get everything back together easier.

I have put the exploded diagram and parts list from the dart manual on the morini club site at the following links:

http://www.morini-riders-club.com/photo ... ploded.jpg

http://www.morini-riders-club.com/photo ... _parts.jpg

The starter is a bit fiddly to get back in, easiest way is to guide it in as a complete assembly, and keep a magnet on a stick handy as it's easy to drop the washers & thrust bearings off the back of the shaft.

Hope that helps, and good luck!
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Re: Sticky starter

Postby clanger9 » 15 Dec 2019 18:48

Brilliant, thanks Tom!

It's the sprag clutch that's sticky. I wasn't sure if it ran in engine oil or dry: you've confirmed that it runs in the oil.
I just gave it an oil change, so I'll give it a run out first and see if the issue clears up. If not, it looks easy enough to dismantle...
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Re: Sticky starter

Postby EVguru » 16 Dec 2019 18:06

The Cagiva era engine manual, which covers the starter motor, is in the members area of the club site.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
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Re: Sticky starter

Postby clanger9 » 16 Dec 2019 19:02

Ah thank you, that manual is much better - I hadn't noticed it before.
It's clear from the pictures in there how to access the starter clutch.
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Re: Sticky starter

Postby clanger9 » 04 Jan 2020 17:50

Update: the starter mechanism is now working fine. It's very nicely engineered.
The parts manual is helpful for showing how it all goes back together.

The rubber cush was in good order. It just needed the sprag clutch cleaning and re-greasing. :D

IMG_1064.jpg
IMG_1064.jpg (133.66 KiB) Viewed 1947 times
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Re: Sticky starter

Postby 3potjohn » 09 Sep 2020 09:15

Not Dart but same starter system on Coguaro
Investigating slight whine from starter gearing.There are 4 shimwashers ,item 10 on the exploded diagram. In my case 2 are 0.95 and two are 1.5mm. Is this by design? At the mo the thin ones are in board. Looking at witness marks has not clarified the correct sequence. One fatter shim on the gear meshing with the starter has a noticeable wear ridge.
Thought about polishing it out.
What to do?
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Re: Sticky starter

Postby clanger9 » 09 Sep 2020 11:56

Unfortunately I didn't take note of the shim order - I just put them back in the same order they came out...
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Re: Sticky starter

Postby morini_tom » 09 Sep 2020 14:11

The thrust washers are all listed with the same part number (part 10 on the dart parts diagram), and no mention of different sizes available.

I have certainly never noticed any of any different sizes and I've had a fair few apart! And they are pretty hard and I've never seen any wear on them.

I will measure up the thrust washers I have in my dismantled engine and let you know
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Re: Sticky starter

Postby 3potjohn » 09 Sep 2020 17:03

Very kind. If they are supposed to be the same spec then the thinner ones look in good nick. Have not run without the bits in to check if the sound is eliminated. May try tomorrow.Been focussing on carb issues which were manifold. Actually the manifolds were the OK bit. Much better now.
If negative I might have a poke about in the clutch which obligingly has a 25mm centre nut. 25mm!!!!!!!
Still that’s Cagiva...give ‘em an inch.....
John
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Re: Sticky starter

Postby morini_tom » 09 Sep 2020 17:32

All four are 0.95 in my dart motor, so it does appear that your 1.5s are wrong.

I have another motor in bits if you want a third opinion but that’s much harder to get to.

With the thicker thrust washers you’ll be loading up the assembly when you tighten the cover, as I don’t think there is intended to be any end float. Maybe also causing the sprag clutch to not be able to freewheel? Would be worth checking the condition of the needle roller thrust bearings incase they’ve been damaged.

How thick is the gasket on your cover? should just be a normal thin (~0.5mm) paper one. If a thicker gasket has been used then maybe thicker shins were used to compensate. But it’s not the right solution. The dart engine I have in bits had one gear in the starter cluster which had moved outwards on the shaft, and to prevent it locking up when the cover was tightened, somebody had fitted a 1.7mm thick gasket. Again, not the right solution.
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Re: Sticky starter

Postby 3potjohn » 09 Sep 2020 19:51

That is very useful. Just a normal gasket,I have not measured it yet. So the next stage is to acquire 2 suitable shims. Do you think they have a hardened surface?
John
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Re: Sticky starter

Postby 3potjohn » 09 Sep 2020 20:52

I should have asked if you have the ID and OD then I might be able to source some without recourse to removing the cover again yet, though that is simple to do.
John
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Re: Sticky starter

Postby morini_tom » 09 Sep 2020 21:57

I would say they are probably hardened and polished thrust washers, and matched to the needle roller thrust bearings- don't forget the sprag clutch cluster is permanently driven by a helical gear and hence the thrust bearings on that gearset, and one half of that shaft at least is always turning.

I just measured mine- the shaft is 12mm diameter and the thrust washer is measuring accordingly at 12.1mm diameter. The OD of the washer is a slightly odd 25.8mm (1 1/64"?)

Looking at the outer cover and gearset I see no reason why you couldn't go slightly bigger on the thrust washer OD if needed. You can't go smaller or the needle rollers would be at the edge of the thrust washer.

The 0.95mm thickness seems to be the tricky bit- I had a quick look at online bearing stockists and couldn't see any 0.95mm thrust washers. But a more thorough search may yield something.

Closest I could see is an SKF thrust washer at 12x 26 x 1 mm https://www.bearingstation.co.uk/products/needle-bearing-thrust-washer-skf-12x26x1mm=46694

I imagine that the 0.05mm thicker thrust washer will be insignificant, and you can split that by using your two 0.95mm washers on the inboard shafts and the 1mm shims on the outboard, as opposed to both 1mm on the same shaft.
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Re: Sticky starter

Postby 3potjohn » 10 Sep 2020 09:06

Ok Tom
Thanks for that link. I’ll update as and when I get somewhere. Having recently sharpened a plane and eight chisels by hand, following the Paul Sellers YouTube vids I may work on the existing ones first.
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