Grinding sound when press starter - RGS

Thanks again Keith. It's good to know I can get the parts from you easily enough. I'll see what I can find a bit closer first. Scotland's a long way off for small parts to come from.  :)

Cheers

Ventodue said:
Should overhauling the sprag be thought of a preventive maintenance thing?  Or does it fit more in the, 'Don't fix it if it ain't broke' category?
See, mine works fine - well, up to now ...  :D
TIA Craig
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I'd be inclined to check it you were going away, or something like that. I had no warning signs.
It stopped working just up the road from home. I can think of a lot worse places to be. On your own, somewhere flat, where a push start means running along with it, and... it's cold, so the bike won't start easy. Or, it's very hot, and you're puffing and sweating like a bastard in one minute.

I'm glad it stalled just up the road.

 
Ventodue said:
See, mine works fine - well, up to now ...  :D

TIA

Craig
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Same here Craig (says he, tempting fate....) - my RGS is still on its original starter clutch guts. Witt ignition makes a big difference to the starting performance and hence the grief on the starter clutch ;)
 
Chappo - sorry to hear of your experience.  However, discussion with those that have suffered sprag problems suggests that there is audible warning of things going awry.  A brief squeek/graunch when releasing the starter button as the engine fires is one tell tale sign of broken plunger springs for example.  Scrumpy discovered this last year on the Isle of Man, having decided before setting off that the noise wasn't that bad and the starter still worked....he also demonstrated that ballpoint pen springs are indeed the fabled get-you-home fix!
DSC07523.JPG
 
Ventodue said:
Hi, 'Wise people wot know',

Should overhauling the sprag be thought of a preventive maintenance thing?  Or does it fit more in the, 'Don't fix it if it ain't broke' category?

See, mine works fine - well, up to now ...  :D

TIA

Craig
Click to expand...

Craig,

I've gone over to the "preventive maintenance" routine on my bikes.  The MkII and 120s are especially prone to sprag failure while the MkI seem to last quite a bit longer.  750 requires overhaul every season, but it does have a hard time spinning the long-stroke.

Weak batteries and wrong ignition timing quickly ruin the sprag clutches.  If squeaks are heard, high time to take off the cover.  Won't fix itself... things only get worse (and more expensive!).

Chappo,

At least I don't see any cracks in the inner rotor.  The witness marks on the rear side of the clutch rotor show the clutch has had a hard time, lots of sideways movement of the rollers.  Check condition of the drive gear where the rollers contact, shouldn't show too many ripples, ie, should be sort of smooth. ::)  They never are...  When replacing the puny little M5 countersunk screws it will NOT suffice just to Loctite them.  Insert an allen socket and give the tightened screw a few firm taps with a light hammer (don't use your Sunday-best Snap-on socket), you'll be surprised at how far further you can then tighten it!  Repeat till no further tightening is possible, without shearing it off.

piet
 
Chappo said:
Thanks again Keith. It's good to know I can get the parts from you easily enough. I'll see what I can find a bit closer first. Scotland's a long way off for small parts to come from.  :)
Click to expand...

all parts in stock in Camira, QLD, bit closer then bonnie Scotland

 
It seems to me that if you are taking of the rotor etc for any reason, it would be sensible to check the sprag clutch.I don't think the springs / their holders get enough lube, because if they did they would not seize as mine did. I recall reading that the 750 s need luring and they have a different design I think I read in the Green Book. Once you hear that graunching sound, you are living on borrowed time and will no doubt be damaging the hardened surface of the sprag clutch, which costs a lot more than a few springs and rollers. Despit mine obviously having been messed about with by the DPO, witness 3 spring lengths, it did ok for 10 years so these things obviously work when all is not at optimum.
 
Thanks everyone.  Think I'll keep my ears open for tell-tale sounds, and then pull it apart next winter.

Thanks again.

Craig
 
a14rgs said:
Same here Craig (says he, tempting fate....) - my RGS is still on its original starter clutch guts. Witt ignition makes a big difference to the starting performance and hence the grief on the starter clutch ;)
Click to expand...

Doubt it, Seth had a witt installed at 3500ks
 
Ventodue said:
  Think I'll keep my ears open for tell-tale sounds,
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well,,  me Miss J gave me no tell-tale sounds.  not even a slight murmur.
edit >  i reckon nothing was of a 'tell-tale' nature.  just the 'usual' sounds. <

and i would have guessed i would hear the starter motor spinning up to over 70,000 rpm?  but alas no.  :(
fortunately the starter clutch immediately let go, after the starter motor had exploded and locked the rear wheel.
lucky Mark
StarterMotor4.jpg
 
Mine on the 3C made a couple of high pitched squeals a while back and Marty volunteered to have a look.It was fine but we replaced the springs for piece of mind.Took Marty about and hr to do,he got good at it with the RGS he had a while back.
 
I?ve got my bike back together, and I have started it a few times. All good, so far.

I went to a nut bolt specialist supplier. They had about half a dozen springs of the right diameter, but only one seemed close to suitable. They are a bit stiffer than the ones I took out, but they were the loosest of the lot the shop had. There was a second place I found while Googling, but they were closed Saturday morning. If I wanted to try something this weekend, I had one choice on offer, so I bought them. Turned out not very expensive. $8.70 AUD. $4.35 for a pack of three.

The new springs hold the rollers in, but not very tightly. If I tip the alternator flywheel, the rollers drop out. 

After the first start, I warmed it up a little, then switched it off. I started it two more times in the next ten minutes, and it started easier these two times than it did before. There?s a bit of an improvement. Remains to be seen how long it holds. I?m pretty confident it will be good. The springs are made in Oz, supplied by a mob in Melbourne (I bought them from Newcastle High Tensile Bolt Company). I reckon I put it back together OK as well. A dab of loctite here and there. I used the same force with the rattle gun to put the bolt back in, as I used to take it out.

Thanks to everyone that helped, I reckon I would have been stuck and wondering what to do without help from you guys.

Here?s hoping I am not posting back saying my starter clutch is mangled beyond description, and I need a new one.  (cheers)  :LOL:  (cheers)



I found the missing spring, it was stuck to the flywheel magnet.

The six original springs, plungers and rollers

SFscBoa.jpg


The replacement springs

msqoqYe.jpg


The surface on the gear where the rollers grip. Piet asked about this.

4kAG4A2.jpg


Roller with original spring

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Roller with new spring

NqPPbAs.jpg



The workshop manual states you need two factory tools. One is a large C spanner to hold the alternator flywheel, while you undo the bolt that holds it to the crankshaft. The other is a puller to get the alternator flywheel off the tapered end of the crankshaft.

52rFCVpl.jpg



If you don?t have these tools, I wouldn?t attempt it without an air impact spanner/wrench (rattle gun), to replace the C spanner, and a bolt to turn into the threaded part of the alternator fly wheel, to replace the puller.

You also need a T15 Torx screwdriver. At least I did, the metal threads holding the roller cover plate on had Torx heads.
To get one starter motor bolt out, you need a long socket bar (about 30cm) with a 6mm alan key on the end.

AWa6h6b.jpg

 
The NSW club has a bunch of these springs,Chris Pritt knows a bloke who makes them,come to think I know him as well.He made a bunch of 1st gear springs for my Husky Auto.Thats a real test of springs and his hold up well
 
Hi Chappo

looks like a thorough "How To" with good photos, thanks!

MarkQLD posted a photo of an exploded starter motor a couple of posts earlier. I have a starter like that as well, occurred on my RGS at about 3,000 miles from new...... but the bike was ridden less than a 1,000 miles, then put away for nearly twenty years, when I resurrected and returned it to service, without touching the starter sprag clutch. There was no noise or warning when the starter exploded on my RGS from the engine running and the sprag spinning the starter at about a million rpm.

now, whenever I rebuild a starter sprag (and I just did the one on my 82 1200 project), I pack everything with high quality grease, the plungers, the hole the plungers go in, etc. I just take a few handfuls of grease and pack it in thick. Seems to keep everything happy and for a long time. Whenever I happen to be in the part of the motor I just pull the sprag, clean it in the parts washing tank, check the springs and plungers, if everything seems ok, then I re pack it in grease.

anyway, packing the sprag in grease works for me. Anyone else do that?

Paul LeClair
 
Paul LeClair said:
Hi Chappo

looks like a thorough "How To" with good photos, thanks!
Click to expand...

Thanks Paul, but I did leave out how I put the gear back into the rollers, that is almost an essay in itself.
I am getting around to including that in the 'how to' thread section.

I found a photo in the gallery, after I had mine back together, where someone had nuts pushing the rollers out wide, with fine wire on the nuts leading down through the centre, so they could be pulled out once the gear was in.
I thought it would take me longer to find nuts, and wire them, than it took me to get the gear in, but if I was doing them regularly, I'd want some sort of tool to make it less frustrating, and I'd go looking for nuts.

I used grease to hold the rollers in place (Red's tip, and the manual says it too), but I did not pack the plungers. I thought the engine provided the lube.
 
I will be buying an electric impact wrench when I get around to it. No compressor to worry about. They are very powerful and now seem to be increasingly cordless.

As regards grease or oil for sprag clutches - we have been here before.
Most manufacturers recommend oil or grease lubrication but NO extreme pressure (EP) additives.

The clutch has a Jeckyll and Hyde personality.
When you press the starter button friction is required to engage the rollers and jam the clutch. When the engine wants to turn faster than the starter/clutch you need friction to disengage the rollers.
However once that is achieved then we don't want much friction at all, otherwise the rollers/gearwheel will get damaged and of course the starter motor gets driven at 70,000 rpm.

I don't know what happens if EP grease is used. I suspect that the clutch struggles to engage.
 
When I was a Yamaha mechanic in the days of the TX750 twin, the sprag clutch was one of the many items that failed frequently (rollers too soft, they wore out in just a few thousand km). The Yamaha one was behind the alternator and only had 3 rollers, and was a buggar to put back together, the rollers would just fall out all the time. I tried a dab of grease to hold them in place during assembly. It worked, but then the sprag clutch slipped when it tried to engage.
But the Laverda one doesn't run in oil and the manual says to grease it  :o, so that's what I'll be doing.

Ken
 
Got a couple of points,I had untold dramas with the kickstarter sprag on my Husky Automatic,it started slipping,no kickstart = boat anchor on these.Only way to get the bearing out was pretty destructive and the replacement bearing was eye watering expensive,$450oz about 15 years ago.The slipping was caused by sludgy oil and debris in the blind housing from the brass friction shoes.No grease,they run in the highest heat resistant 5wt mineral oil available.These days Ohlines shock oil.I am thinking engine oil ok,grease not so good BTW Ken there is a sudden appearance on Adventure Rider Vintage section,heaps of posts re TX 750 sprag fixes.Someone somewhere is always working on oddball fixes for old bikes.
 
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