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Special extended Christmas edition of knackered bike - now with added mystery

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eternally_troubled
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by eternally_troubled on Tue 26 Dec 2017, 7:12 pm

You really have to go some to get hydrolock to happen - as Andy has said I'd be more worried about what the petrol has stripped off while it has been sloshing around. Mind you, you haven't run it much so it will probably be fine.

For the petrol to have got into the sump the needle valve in one or other carb has to be knackered *as well* as the petcock/vacuum valve...





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trevor machine
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by trevor machine on Wed 27 Dec 2017, 5:56 pm

Well, that's reassuring ET. Thanks. This morning we replaced oil and filter. We also took the petcock apart - diaphragm and spring seemed good. We flushed petrol through the entire petcock assembly, which we'd unbolted from the bottom of the tank - no sediment could be detected in the tray that collected the flushed fuel.

What we knew about tank and petcock - the former seems free from any contaminants now. The latter too - although it is still not working properly because the "off" setting dripped. NB we tested the tap whilst removed from the tank - by filling the long tube with fuel, and also by filling the bolt-level "reserve" reservoir. We dismantled and cleaned as many of the petcock's components as we could, but some are riveted. At any rate, the tape operated more freely and would not stick in any of the three positions. However, there was no really obvious reason why - as we'd identified no damaged parts, and not really found much dirt or contaminant.

We then began to think about trying to start the bike. With the tank still off, and stored in the garage awaiting a "new" petcock assy, we filled the carbs via the tube we'd detached from the tank. We stuck a small funnel into this tube, making it easier to see if the level of fuel was altering.

As a matter of course, we also removed plugs, cleaned them, checked for sparks, and bunged 'em back in their goddamn hidely holes.

So - was the level of fuel in the funnel changing? Because if it was, wouldn't this be a symptom of faulty needle valves in either one or both carbs? Well in the event, it didn't seem to be changing. If said valves *are* suspect, the amount of fuel they're allowing to ingress is imo minimal.

Finally, we went for a start. First full choke, no throttle. In the very first instance it sounded like it might catch - but almost immediately there was an explosive back fire and then it really didn't wanna know. Second - no choke, some nurse-maid throttle. Yeah - definitely not playing. Not at all.

We were confident we had spark, and that the bike was fuelling at least in a way that would facilitate proper starting, warming through, and idling. And yet nothing.

Next we'll try to at least examine parts of the carbs. Although our appetite for carb removal and dismantle is precisely zilch.
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Jameshambleton
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by Jameshambleton on Wed 27 Dec 2017, 6:24 pm

I'd go back to checking the main grounding point for the loom, It's under or ontop of the reg/rec under the left hand side panel
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skyrider
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by skyrider on Wed 27 Dec 2017, 6:28 pm

they usually just rot away after a few years , could be a new eyelet needed
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by rick1 on Thu 28 Dec 2017, 12:02 pm

I had the same problem a few months ago, petrol in the engine, drained the oil refilled put on a new filter and away she went. I now turn off the fuel when ever I park and have had no trouble since.
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trevor machine
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by trevor machine on Thu 28 Dec 2017, 8:51 pm

Just to be clear - I have a spark. I have fuel.

The plugs were out again today. The spark is not fat but it's there on both plugs, made to arc continuously.

Fuel I supply by tipping down the tube once the tank was off. Plus in any case, the plugs are wet when taken out after attempting to start.

The bike wouldn't bump in second either.

I start to wonder if I've got compression, perhaps as a consequence of bent valves from hydrolock. Sounds pessimistic I know, but we're scratching our heads here. Probably going to get the bike recovered to my preferred indie fettler in town, see what he can turn up. Mebbe a comp test along the way.

Me and my mate, we've run out of options, patience, knowledge and experience. We checked the carbs' diaphragms / bellows today thinking the huge backfire of the other day might've damaged them. They were fine.

So yeah. F*** knows now. There really seems to be no obvious reason why the bike won't start.
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skyrider
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by skyrider on Thu 28 Dec 2017, 8:59 pm

yea if you have come to a dead stop its always better to seek guidance from someone who knows instead of doing expensive damage
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skyerae
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by skyerae on Thu 28 Dec 2017, 9:12 pm

I agree with Skyrider, keep us informed though as I must admit I am intrigued as to why this bike won't start.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by skyrider on Thu 28 Dec 2017, 9:16 pm

I reckon go to your usual bike guy and bend his ear about whats happening or in this case not
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trevor machine
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by trevor machine on Fri 29 Dec 2017, 9:49 am

Latest thought from Mike my mate on this.

Going back - back to the issue with the starter motor. How it was stuck. How when the start button was thumbed, there was just a single, distinctive "CLICK" - and this despite a fully charged battery.

Remembering all that - because me and Mike are quite firmly of the view that many if not all of the various problems previously mentioned in this thread are interrelated. We're both quite logically minded people, but especially Mike who's by nature methodical, clear of thought, and instinctively captivated by these kinds of problems.

So - remembering the stuck starter, could it's "stuckness" have been a consequence of a sump i.e. engine full of liquid - full of oil and fuel? Is it possible the motor was refusing to crank because there was simply no room for the parts to move in? Could it be that my "bumping" the rear wheel round somewhat was sufficient to create extra space to contain the increased oil/fuel volume, and therefore permit a starting procedure to occur?

If so, I'm kind of back to erring on the pessimistic side. I think parts of the motor could've been forced to operate in far too compressive a state.

None of this speculating changes my immediate plan, which is to get the bike recovered. I think the first job I will ask my mechanic to do is a comp test. I want to know whether the bike's basic mechanical functions are in order before time is spent disassembling carbs and petcocks, etc.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by teamster1975 on Fri 29 Dec 2017, 6:23 pm

How does it sound when you crank it without the plugs in? Next step would be compression test, it would be worth dropping a spoonful of oil into each bore and turning it over without the plugs in, then try firing her up again.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by trevor machine on Fri 29 Dec 2017, 7:13 pm

It sounds just as it's always sounded. In short, like it's got compression. One thing I haven't mentioned - we got the crank case cover off, and turned the engine by hand. Mike's feeling was that it should've been harder to turn it - but when I pushed him on that he did admit it'd been a fair while since he'd turned an engine by hand and couldn't really remember how much resistance there should be. But I think he was just trying to be optimistic for me.
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eternally_troubled
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by eternally_troubled on Fri 29 Dec 2017, 7:59 pm

Just a thought:  have you dried out/replaced the air filter?  It is possible that the petrol overflowed back into the airbox... if any petrol is hanging around in there it won't help anything working well.

Also, you must have *some* compression or there would be almost no resistance when turning the engine over.

Assuming you haven't taken it to get fixed (or to the scrappie) then it might also be worth taking the plugs out and leaving them somewhere warm and dry (or at least, not too cold and dry) overnight, just to make sure that they have properly dried out.  That or use a hair-dryer on them...

It will also be beneficial to leave the spark-plugs out as it will allow any petrol left in the bores to hopefully escape by evaporation.

If the CB500 was an air-cooled bike where you could get to the spark-plug hole I'd suggest you put your thumb over the hole and crank the engine - if you can hold it over the hole there isn't enough compression!  Sadly this isn't really possible on a water-cooled bike unless you have madly long thumbs.

Anyway, after the above, if you are really determined to start it then turn the engine over a few times by hand - assuming there are no 'orrible noises while turning by hand then get a charged car battery and some long jump leads and connect it up in place of the CB500 battery and press the button.

The car battery should allow you to turn it over on the starter for long enough to get it going, plus the voltage won't sag as much as the 'real' battery which will give the sparks a bit of extra oomph.

Anyway, whatever you end up doing, best of luck...

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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by sullivj on Sat 30 Dec 2017, 7:32 am

Can't add much worthwhile comment, but watching with interest to see what the problem is.

I would have started with a new battery and check of the grounding points. Batteries that are only half working can create all kinds of oddities.


Last edited by sullivj on Sat 30 Dec 2017, 2:42 pm; edited 1 time in total
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skyrider
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by skyrider on Sat 30 Dec 2017, 2:22 pm

iye weird and wonderful thing are battery's and so are the fancy chargers
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by Jameshambleton on Sat 30 Dec 2017, 2:51 pm

From diagnosing my current electrical issues there is only 2 proper grounding points on the bike.

One is under the regrec to the frame and the second is from the under the statermotor/engine.

I've wired in an additional ground running from the ground lead of the sidelight to the top rad mounting. Which appear to have sorted my issue currently, which is somewhat the same as yours. turn over turn over ect ect and then a back fire and then kinda wants to start.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by trevor machine on Mon 01 Jan 2018, 7:19 am

Okay cheers James. That's interesting. I do seem to remember reading somewhere that 90% of all fuelling issues are electrical. Laughing

Or words to that effect.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by skyerae on Mon 01 Jan 2018, 9:34 am

On my aforementioned FZR there was a host of electrical issues, a flat battery was one of the issues. I had to try and bump start it most days and the battery got so bad it felt like it was running out of fuel one day (go figure?) The wiring loom was a mess, thanks to to the previous butcher, sorry I meant owner. I eventually thought stripping it and rebuilding it was the best option and last year sold it as a complete bike (if you put it all back together) That was after I got the CB and it is fine to have a bike that seems to be mostly reliable. Only had issues with a duff coil and the front brake both of which I respectively replaced and overhauled.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by trevor machine on Mon 01 Jan 2018, 10:43 am

Yeah it's very possible this is, all of it, down to a bloody electrical thing. However - and I do want to emphasise these points - the sediment in the tray upon draining the carbs; the sump full of oil and petrol; the knackered petcock that lets petrol drain through when in the off position.

I also want to spell a second point out too - because it's possible this detail got lost in the sturm und drang of my righteous wrath upon discovering that my bike was being...difficult. My Honda. My 1990s Honda. Is there a more invincible piece of machinery on the planet?  

I digress - the detail. We always ask the question "what has changed?" It's a really good question to start with when tackling an issue like this. Quite often we say "erm nothing." But think. Think verrryyyyy carefully. Have you done something that you don't normally do? Something that's broken a habit? It could be seemingly irrelevant. A mere detail. A piece of mechanical minutiae.

Well, I have that detail.

I take you back to 2-3 months ago. I made the uncharacteristic decision to "lay the bike up". Normally I just ride right through winter. Which I was anticipating doing again this year - but on the 9 and also the klx (for off-road duties). It looked like the 500 was going to be hibernated. So...I tried to drain the carbs by stalling the bike, and screwed an Optimate lead onto the battery terminals. Now it so happened that the bike never stalled. But I just thought ah f*** it, the bowls are probably nearly dry by now and the rest of the fuel can just damn well evaporate. So I went back into the garage and turned the bike off.

A few weeks later a dry day materialised and I thought ah sod it let's wake the 500 up and stretch its legs for a few hours. But it just would not bloody well start.

So I rang my other mate, Phil. Told him of my woes. He said what have you changed. That brilliantly simple and oh so crucial question. I told him of the Optimate lead - he said well there you go then. You obviously haven't tightened the leads on tight enough and now it's not making a proper connection.

I knew I had. But I also knew I had to check the connections. And there they were - tightly connected. I felt vindicated. I wasn't the slap-dash dosser that Phil and Mike and everyone else know me to be. I patted myself on the back...and shortly after it probably started raining or got cold again, covering the road in frost. At any rate, I forgot about riding again for another few weeks.

Now microscopes out, because here's that crucial difference. Here's the detail that led to my demise, that's possibly bent f*** out of several valves and effectively trashed what was - a couple of months ago - a very fit and healthy 500. Yeah, what I did that I've never done before - a casual, carefree yet well-intentioned moment of mechanical sympathy?

TURNED THE FUEL OFF.

That's all I did. This innocent little gesture, intended to guard against the bowls filling again, and thus ensuring that nasty ethanol was held at bay, that simple twist of the petrol tap. It f***ed my bike.

Well...it's possible anyway. Suffice it to say it's my preferred explanation at the moment. I *never* turn my fuel off. NEVER. I probably should. But I never do.

And here's the irony of it all. The reason you ARE supposed to turn your petrol off is to guard against hydrolock i.e. fuel making its way down into the bottom of the engine, eventually filling it, and creating a solid wall of liquid for various moving parts to smash into in a bid to compress the air and fuel mixture which has had its valuable bit of space stolen by this destructive volume-robbing mass.

In other words, what you're meant to do is to turn your petcock to "off" because, it being a carb'd bike, there's a chance that you've got a stuck float needle or whatever. If you DO have such an issue, your carb's bowls will not know when they're full, and your cup of petrol will brimmeth over.

Now this is obviously a bit of an irony.

I'd done the RIGHT THING. I'd followed the advice and guidance set forth in the owner's handbook. When not riding the bike, turn the bloody fuel off.

First time in my life I actually sodding do this and what happens. I've got a knackered petcock and the precise opposite of what I want to happen, happens.

Well okay yes, this diagnosis also relies upon something being stuck in the carb, and it being unable to tell the tank to stop sending down more fuel. But you kind of get me.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by skyerae on Mon 01 Jan 2018, 11:06 am

Oh man, I do feel for you  Crying or Very sad

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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by sullivj on Mon 01 Jan 2018, 12:01 pm

I feel your pain.

I do turn off my petrol, as it helps me remember to do it on my 1950's bike.

I'm not riding at the moment, but when I do, I will check the oil level to make sure I'm not about to suffer the same fate.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by skyerae on Mon 01 Jan 2018, 12:38 pm

I never ever turn off my petrol on the CB whilst the VFR doesn't even have a stopcock, maybe because it is fuel injected?
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trevor machine
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by trevor machine on Mon 01 Jan 2018, 5:28 pm

Cheers guys. I took the tank and petcock round to Mike's this afternoon, for one last lookie-look before I get it recovered. "Off" is definitely knackered. We clamped the smaller narrow hose tight, and ran the fatter one into a container, just in case 'off' wasn't working. Which it wasn't. The was a lot of fuel coming down the carb connector tube we created.

Y'know, it's quite a different design to the one on e.g. a W650. Like the 500, the W's tap has three settings. However, in place of "off" is a "prime" function. There are the standard 'on' and 'reserve' - but no off, and instead 'prime'.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by Jameshambleton on Mon 01 Jan 2018, 6:53 pm

on and reserve will be vacuum operated. Prime just lets the fuel be gravity fed.
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Re: Special extended Christmas edition of knackered bike - now with added mystery

Post by eternally_troubled on Mon 01 Jan 2018, 11:10 pm

@trevor machine wrote:
...

Now microscopes out, because here's that crucial difference. Here's the detail that led to my demise, that's possibly bent f*** out of several valves and effectively trashed what was - a couple of months ago - a very fit and healthy 500. Yeah, what I did that I've never done before - a casual, carefree yet well-intentioned moment of mechanical sympathy?

TURNED THE FUEL OFF.

That's all I did. This innocent little gesture, intended to guard against the bowls filling again, and thus ensuring that nasty ethanol was held at bay, that simple twist of the petrol tap. It f***ed my bike.

Well maybe :) Let's hope you haven't knackered it.

Do you normally ride it right to the end of the normal tank range, so you have to switch to reserve? 'cos if you do that you tend to turn the tap (in at least one direction) once every tank of petrol. Assuming you *don't* do that when you switched to 'OFF' it could have been the first time it moved in ages!

Anyway, as I said before, best of luck.

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