Most motorcycle problems are caused by the nut that connects the handlebars to the saddle.

Help! Seized?

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supersim65
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Help! Seized?

Post by supersim65 on Sat 10 Sep 2016, 9:46 am

I'm so pissed off. I literally finished repairing my other bike last night, and the CB has broken this morning when I tried to start it. Can I not just own working bikes for a day?

So, it's just finished 3500km round Europe. Did not miss a beat. Been ridden once in the last 4 weeks, no problems.

Last night, I started it up, just to warm it up and keep it active. It back fired when it started, but after the initial cough warmed up well and idled beautifully as always. I noticed the tire was a bit low on air, and the valve looks wasted, so I thought I'd go get it replaced this morning.

This morning, I hit the starter button, it turned over once, then made a clunk sound similar to when it goes into 1st gear, and locked up solid. I can hear the starter engaging, but it won't turn over. I can move it into 1st, N and 2nd. So the clutch seems OK. Dead starter? Would I still be able to hear it engaging if it was dead? I suppose I should try bumping it to find out.

I feel like the engine seizing that fast seems unlikely, can anyone help me troubleshoot?
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eternally_troubled
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Re: Help! Seized?

Post by eternally_troubled on Sat 10 Sep 2016, 11:45 am

I'll be willing to bet that the engine isn't seized!

So you are pressing the starter button and getting a clunk/click type noise?

It is possible for the starter when worn and dirty inside to get into a situation where won't turn and the bike won't start - luckily you can get around this very easily:

Switch off the ignition, put the bike into second gear and push it forwards until the engine has turned over (this will require a bit of a push, not because it is seized, but to get over the cylinder compression!) this will also turn the starter-motor to a new position and you can try starting again.

If the starter was the problem then the bike should now spring into life, assuming you haven't flattened the battery. You have also demonstrated that the engine isn't seized Smile

To fix this problem you need to take the starter motor apart and give it a clean up and replace the brushes if they are worn (they might not be, so it's worth taking it apart anyway). It isn't too difficult - there is a thread on here about how to do it.


Where did you go on your European trip? Got any photos? (you can bet we'd like to see them)
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supersim65
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Re: Help! Seized?

Post by supersim65 on Mon 12 Sep 2016, 12:35 am

Thanks Troubled.

I can't bump it, the wheel skids in 3rd even. It's really stuck. I can hear that starter relay though, so I'll have the starter out and serviced as soon as I can. I think it's a good call.

I've been meaning to write something about the trip. I made a start this evening. See what you think. More to come if people are enjoying it. 

http://www.cb500club.net/t4788-ride-report-alpine-tour-2016#43388

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Re: Help! Seized?

Post by sullivj on Mon 12 Sep 2016, 7:14 am

If you remove the inspection cover on the LHS (with the large Allen hole) you could try rotating the engine with a socket, just to make sure it turns.

Could the cam chain tensioner have failed? I doubt it.

I've never heard of a CB engine seizing.
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eternally_troubled
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Re: Help! Seized?

Post by eternally_troubled on Mon 12 Sep 2016, 8:21 am

@supersim65 wrote:Thanks Troubled.

I can't bump it, the wheel skids in 3rd even. It's really stuck. I can hear that starter relay though, so I'll have the starter out and serviced as soon as I can. I think it's a good call.

I've been meaning to write something about the trip. I made a start this evening. See what you think. More to come if people are enjoying it. 

http://www.cb500club.net/t4788-ride-report-alpine-tour-2016#43388


Thinking about it I'm not really sure if it is possible for the starter to 'lock' the engine properly, because of the starter clutch, however if the starter clutch was on the way out or stuck it probably could.  However once you've got the starter off you will be able to test both the starter and the rest of the bike.

Haynes has a pretty good explanation of how to take the starter motor apart and clean it, which might be worth doing even if it is isn't the culprit. It also has a fairly good section on the starter clutch (just in case!).

I enjoyed the beginning of your story, so please keep on writing it!
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Jameshambleton
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Re: Help! Seized?

Post by Jameshambleton on Mon 12 Sep 2016, 8:39 am

put the bike in 6th gear, remove the front sprocket cover and then get a 14mm socket on it and turn it anticlockwise. oh and make sure the bike is on its mainstand.

I found that my bike locked up a lot in 3rd when trying to bump it, so I use 2nd.
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eternally_troubled
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Re: Help! Seized?

Post by eternally_troubled on Mon 12 Sep 2016, 3:07 pm

@Jameshambleton wrote:put the bike in 6th gear, remove the front sprocket cover and then get a 14mm socket on it and turn it anticlockwise. oh and make sure the bike is on its mainstand.

I found that my bike locked up a lot in 3rd when trying to bump it, so I use 2nd.


For actual bump starting (like when you battery is knackered) I agree - 2nd seems to work best.  Although if it is icy you can get the rear wheel to skid in any gear :)   (icy is not good for bump starting, sadly the most likely time for your battery to fail)
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Grarea
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Re: Help! Seized?

Post by Grarea on Mon 12 Sep 2016, 3:41 pm

I understand that for bump starting second is good.
ie first being too low a gear.

But is there any reason (if testing whether it is seized) you wouldn't test it in first?
Wouldn't that just make life easier?
Pop into first and push it.
Or am I being dopey?
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supersim65
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Re: Help! Seized?

Post by supersim65 on Sat 17 Sep 2016, 1:55 pm

The higher the gear, the easier it is to turn over. However, in the higher gears, you won't turn it fast enough to actually start it. 2nd is the perfect compromise for starting it after you leave the headlights on overnight. I can usually start it on my own, running along side in second gear pretty easily.

Developments...
1. Starter out, apart, cleaned, inspected. No apparent problems. Brushes have plenty of life. Now re-fitted again.
2. Engine wouldn't turn over any better  with the starter out on the bench anyway.
3. I could probably mess around in different gears, and with sockets to try and rotate the engine. But I know that somethings seizing it in place, so forcing it harder seems like a bad idea.
4. I'll have a look into the starter clutch next. I didn't know that was a thing.
5. Any more ideas?
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supersim65
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Re: Help! Seized?

Post by supersim65 on Sun 25 Sep 2016, 9:44 am

Starter clutch is apparently in working order. With the left side off, I can rotate the assembly anti-clockwise, but I can't rotate it clockwise. Which is how it's supposed to work.

I guess I'll take the right side off and have a look at the clutch while there's no oil in the engine.
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supersim65
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Re: Help! Seized?

Post by supersim65 on Sat 01 Oct 2016, 10:45 am

I think I've fixed it.

With it all back together, the same problem occurred. So I spent a bit more time with the battery and starter electrics. The batteries in the last throngs of life, but reads OK with a meter. Maybe a bit low under load. So I cleaned a few contacts between it and the starter. 

While I was testing it under load (measuring the voltage across the battery while pressing the starter button) I held the starter for about 6 seconds or so. Just as I was about to let go, the engine turned over once, then it roared beautifully into life (fresh oil, beautifully maintained engine). 

Looks like a dying battery after all that.

No idea why I couldn't bump start it. Not sure if I perhaps re-seated something when I had the side off.
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Beresford
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Re: Help! Seized?

Post by Beresford on Sat 01 Oct 2016, 11:14 am

It's possible that if your chain wasn't perfectly adjusted that it could 'bunch up' on top of the drive sprocket and jam. This is because on a push start the chain tension is on the lower chain run and the top run is being 'pushed' forward not pulled.
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supersim65
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Re: Help! Seized?

Post by supersim65 on Sun 02 Oct 2016, 12:13 am

I also put this together based on a useful article I read...

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eternally_troubled
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Re: Help! Seized?

Post by eternally_troubled on Sun 02 Oct 2016, 12:17 pm

That chart makes sense to me.

I'm still a little baffled by what might have been 'locking' your engine (I say 'locking' because it obviously wasn't actually locked).

I've certainly had the 'nearly flat battery problem' before where the starter can't quite make anything work.


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