Starter motor problems.

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tony.mon
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Re: Starter motor problems.

Post by tony.mon » Tue May 24, 2016 7:42 pm

Triad wrote:Hello! Sorry to resurrect an old thread but... I'm having troubles with the starter clutch/sprag.
The starter motor is fine, turns but some gear slips and the bike won't start. The teeth of the next wear (where the motor engages) look fine too... so which part could be worn?
My mechanic still has to open the carter to find out but I wanted to save time and fine the parts to get back on the street asap. Any advice?
Transfer gears.
I have spares, if you need one. Visually they look ok, but the screeching noise is the giveaway.
They're easy to fit, remove the lower front cct tensioner blade bolt and it goes in- don't follow Honda's method as it takes longer.
It's not falling off, it's an upgrade opportunity.

Triad
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Re: Starter motor problems.

Post by Triad » Tue May 24, 2016 7:48 pm

http://s1366.photobucket.com/user/Prome ... m.mp4.html

Video of the problem. The bike was connected to my car (with the engine on) so it's not a battery problem and you can hear the starter motor "slipping".

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tony.mon
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Re: Starter motor problems.

Post by tony.mon » Wed May 25, 2016 2:05 pm

Please refer to my previous diagnosis.
There!
Now you have a second opinion.
It's not falling off, it's an upgrade opportunity.

Triad
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Re: Starter motor problems.

Post by Triad » Wed May 25, 2016 4:56 pm

The problem is, I need to open the carter to find out the worn gear and replace it. They're a few, as you know. It will take time. :sad2

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tony.mon
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Re: Starter motor problems.

Post by tony.mon » Wed May 25, 2016 8:07 pm

Triad wrote:The problem is, I need to open the carter to find out the worn gear and replace it. They're a few, as you know. It will take time. :sad2
You can't tell by looking at it and measuring the amount of slip is difficult, requiring some hi-tech equipment.

If the starter motor turns but the engine doesn't; it can't be anything else.
It only takes an hour to change, and you don't even need to drop the oil.

But what's a carter?
It's not falling off, it's an upgrade opportunity.

Triad
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Re: Starter motor problems.

Post by Triad » Thu May 26, 2016 4:51 pm

The "carter" is the engine base. Yeah, with my mechanic I removed the flywheel to check what was going on.
All the gears are fine, everything turns but I guess the starter clutch is gone as the flywheel doesn't move. I found a new one (original Honda) for €70 or the whole big gear+stater clutch used for €100 or so.

VTR Phoenix
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Re: Starter motor problems.

Post by VTR Phoenix » Thu May 26, 2016 6:51 pm

Triad wrote:The "carter" is the engine base. Yeah, with my mechanic I removed the flywheel to check what was going on.
All the gears are fine, everything turns but I guess the starter clutch is gone as the flywheel doesn't move. I found a new one (original Honda) for €70 or the whole big gear+stater clutch used for €100 or so.
The starter clutch only moves one way and locks if tried to turn the other way, this is due to the sprag bearing. If it turns both ways then the bearing has gone but you would also get a graunching sound and what sounds like cogs trying to eat themselves when trying to start it. That doesn't sound like the problem you have.
If it aint broke, get your bloody hands off it!

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tony.mon
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Re: Starter motor problems.

Post by tony.mon » Thu May 26, 2016 7:47 pm

Oh, God, he's still not listening.....it's not starter motor, it's not sprag clutch........so let's see, what's left?

There are two mechanisms you need to consider:
1. The sprag clutch
2. The transfer gears.

Dealing with the sprag clutch first, it's a simple enough design- a circular array of rollers allow "free-wheeling" in one direction but locks in the other. It allows the starter to push the engine round ( to get it started) but the engine can't push the starter motor round. Same game as the free wheel in a pushbike rear hub.
You also get a complicated version in some designs of slipper clutch, and a heavy-duty but basic version in a lock-up clutch for drag racing.

The transfer gears consist of two gears locked together- one is fixed (welded, usually) to the shaft going through them both, but the other is just pressed on.
The second, "pressed-on" gear, has merely an interference fit onto the shaft going through them both.

This means that, should the crankshaft be held in place due to a mechanical problem, the gears will rotate, one against the other, and prevent the starter motor stripping the teeth from the transfer gears, the starter motor pinion or sprag clutch outer gears.
The starter motor generates lots of torque, and so it is necessary to have a way for excess torque to be released before damage occurs.
But whenever this takes place, the second gear wears the interior of its mounting hole, and/or the shaft it mounts on wears a little, and so the torque required to make it slip decreases with wear.
This results in the gear slipping under normal usage conditions.

To check for wear:
Firstly, strip out the sprag clutch.
Occasionally, you might see the the rollers, instead of being round, have flats worn in the outer circumference of each roller.
If you can't see any out of round, replace the transfer gears with known good ones.

So, as per my diagnosis, the sprag clutch is still functional, but the wear on the transfer gears means that they cannot now deal with enough torque to turn the engine.

This is my final word on dealing with your issue, without wishing to cause offence you seem to be a bit hard of understanding.
FFS, just replace the bloody gears and let us move on.
Being in denial doesn't get your bike fixed.
If your "mechanic" can't fix it, give the bike to someone who can.

He might suggest that you have the two gears welded onto the shaft- ask why, if that's a good idea, Honda didn't do that in the first place?

Or, I'll give you £300 for your bike as is, fit new transfer gears and sell it on for a profit; you can buy something else.
I did exactly that with someone else whose "mechanic" replaced the sprag clutch with a new (expensive) Honda one, then couldn't understand why it still didn't work. I had it fixed and running in an hour......and sold the new sprag clutch into the bargain.

Oh, and I have a 2nd hand set of good transfer gears for £40 inc postage to the UK. If you're outside the UK, suggest that you buy the Honda ones.

Lastly, please don't stick your old ones on Ebay.
It's not falling off, it's an upgrade opportunity.

Triad
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Joined: Thu Feb 25, 2016 2:51 pm

Re: Starter motor problems.

Post by Triad » Thu May 26, 2016 8:13 pm

We checked and all the gears rotate... even the big one on the flywheel. But the flywheel will only move a little once on maybe 3-4 attempts. So it must be the starter clutch... what else?
If they all rotate but can't transfer the motion to the flywheel, I guess the starter clutch is the only part to blame.

VTR Phoenix
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Re: Starter motor problems.

Post by VTR Phoenix » Thu May 26, 2016 8:18 pm

The big one on the flywheel? Isnt that the starter clutch/sprag bearing? The flywheel should only rotate when the engine is turning over. If it moves without the engine turning over then maybe check the woodruff key to make sure that's in and not damaged.
If it aint broke, get your bloody hands off it!

VTR Phoenix
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Joined: Sat Jan 16, 2016 12:07 pm
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Re: Starter motor problems.

Post by VTR Phoenix » Thu May 26, 2016 8:21 pm

What Tony is saying is that the two small cogs on the same shaft should not turn independent of each other unless under heavy load, if they do move independently quite easily then that's your problem.
If it aint broke, get your bloody hands off it!

Triad
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Joined: Thu Feb 25, 2016 2:51 pm

Re: Starter motor problems.

Post by Triad » Thu May 26, 2016 8:25 pm

Nope, the woodruff is fine. I'm sorry if I can't really explain the problem but I'm italian and my English isn't good enough for technical stuff, I'm afraid.

http://www.bike-parts-honda.it/pieces-h ... STORM.html

These are all the parts involved, right? My mechanic blames the n.5 but Tony is blaming the n.1, right?

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tony.mon
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Re: Starter motor problems.

Post by tony.mon » Thu May 26, 2016 8:40 pm

Whatever.
Good luck.
It's not falling off, it's an upgrade opportunity.

Triad
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Joined: Thu Feb 25, 2016 2:51 pm

Re: Starter motor problems.

Post by Triad » Thu May 26, 2016 8:46 pm

I'm absolutely NOT arguing here, just wanted to be sure of what I need to check. I accept your diagnosis, tomorrow will go to the mechanic's workshop to tell him he's wrong and to check the gears you pointed as the problem. And just to confirm everything, the clutch rollers looked absolutely normal. I guess I'll have the gears welded while waiting for new ones.

VTR Phoenix
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Joined: Sat Jan 16, 2016 12:07 pm
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Re: Starter motor problems.

Post by VTR Phoenix » Thu May 26, 2016 8:58 pm

Yes, so number 3 should turn one way and not the other by hand quite easily, if it turns one way easily and sometimes turns the opposite way before locking up then number 5 is the problem and needs to be replaced. If it only turns one way and no matter how many times you try will not turn the other way then number 1 is the problem. I would definitely check the starter clutch several times before deciding that is the problem as they are not cheap parts (I just had to replace one in a Suzuki) it's not the sprag bearings that go but the spring that sits around the sprags loses its strength over time and relaxes so the sprags don't make enough contact to stop it spinning the opposite way.if you have the cover off but everything else assembled then spin the motor over while keeping an eye on number 1 and see if they move independently, if they do then replace.
If it aint broke, get your bloody hands off it!

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