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Chat 3

First the answer to the question, "how does the chain and sprocket system work on the vintage bicycle" in the photograph.
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Nobody sent me the correct answer but some were on the right lines.  There are two sprockets on the rear hub.  Each sprocket has a freewheel.  The smaller sprocket works as normal.  When you pedal forward you go forward.  When you stop pedalling the bike freewheels.  The larger sprocket also has a freewheel but fitted to operate the other way round so if you pedal backwards it drives you forward.  The gearing is lowered due to the larger sprocket now being driven, useful for going up an incline.  I think the key to how this works is the very small sprocket mounted below the chainstay.  Its position means that the chain is moving over the sprockets in the opposite direction to one another. (Did you follow that?����)
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Posted by John Earp 28/03/2020:
I was supposed to be having a total right shoulder replacement last Monday at Queens Hospital but obviously that’s been postponed for the foreseeable future.
So it’s been a funny old week: After taking early retirement from Bass/Molson Coors over 10 years ago I’ve had the house pretty much to myself during the week.
My wife and two sons work at Molson Coors  - the lads left home about the time I retired - and until last July when she decided to have Fridays off my wife also worked full time.
That’s all changed now she’s working from home’!
Anyway I’ve worked in the garden, pressure washed the garden slabs, built the patio table and put the garden furniture out, mended the guttering, fixed a new house number up and cleaned our cars and finally today I thought I’d just adjust the float level on my MZ 250 - as sometimes if I leave the fuel switched on overnight I get a slight fuel seepage from the overflow, I thought a couple of hours should see it done - wrong!!
I disconnected the fuel pipe, throttle and choke cables, removed the clamping bolts and removed the carburettor - after removing the float bowl I checked the float height against the Haynes book settings and also checked the needle valve, it all looked pretty good but I thought I’d adjust the float tabs anyway as I’d got the float out - just a bit.
I then put it all back together - I even found a piece of clear plastic pipe to go on the overflow - I re-connected the fuel pipe and turned it on - happy days I thought as I prepared to start the bike up - however, just then I noticed a steady stream of petrol exiting the new piece of overflow pipe!!
Oh well back to the drawing board, stripping it all back off again I thought another slight adjustment should see it through - after draining the float bowl and removing the float something made me shake it next to my ear and I heard that familiar swishing noise - yes one of the floats had sprung a leak.
I served an engineering apprenticeship at Renold Chain - I even met my wife Rena there - she was 17 I was just 20 - but I don’t hold that against them!!
Anyway getting back to the MZ float -I did a bit of gas and stick welding at Burton Tech College as an EITB apprentice and a bit of brazing but alas no soldering.
I can manage to get the solder to stick to electrical wires but I’m technically challenged when it comes to floats.
I dunked the float into a Pyrex jug full of boiling water and watched the steady stream of bubbles from the soldered joint.
Easy I thought - soon have that sorted - wrong - an hour and two rolls of solder later I’d now got more bubbles than a glass of lemonade - Plan ‘B’ I located a new float online for around a tenner!
So there we are - carb off, bike parked up and a new float and valve plus some rubber bits on order and I don’t even know if this will cure the problem.  I rang my order through this morning, the very helpful lady In London who took my order was most apologetic that she wouldn’t be able to post it till Monday as she’d already had her one walkout to the post office today.  I explained I wasn’t going anywhere anyway!  I’ll probably leave the parcel a bit before I unpack it, can’t be too careful!
To be honest it’s given me a chance to give the carburettor a proper clean and lubricate the cables and a few other jobs.
I’m taking my time as I've got two 5 litre tubs of Dulux Natural calico vinyl silk emulsion and some white gloss in my garage, I've been avoiding them for ages but fear I won’t be able to do so much longer!  (I've dragged two tubs of paint out of the shed with a view to painting the en suite, not sure if I'll find time to get around to doing it.����  I hate decorating.  Eddy.)
P.S. Update, apparently the Dulux natural calico is no longer the preferred colour - every cloud has a silver lining ����
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Posted by Mick Dughan 28/03/2020:
Good morning Eddy,I am enjoying the postings, and think others will also.
I am sending you one of my own,a true story (you could not make it up).  Back in the 1980s when we all worked for a living,I was the Electrical Engineer at Cadley Hill colliery near Swadlincote.
Usually my last duty of the day was to go through the back door of the electric workshop and check that all was well with the Shift Charge Engineer and afternoon electrician.
On this occasion as I entered the workshop I witnessed my two members of staff plus a third miner and a Honda 50cc motorcycle.
Expecting a telling off the Charge Engineer was quite relieved to discover that I was keen on motorbikes, and I was told that the miner had just tried to start his bike but that the key would not turn, they had tried WD40 with no luck.
I suggested two options, either hot wire it or remove the ignition switch for further investigation, the miner opted for removing the switch.
This involved taking part of the headlight cowl and some plastic trim off and disconnecting the wiring to eventually remove the switch assembly.
With the switch in my hand and inverted I sprayed it again in the hope of dislodging any foreign body,but the key still would not turn.
Having been trained to think logically I then asked the miner if he was sure that he had the right key?
He replied “Yes it’s the only key I have “
Also being known to ask the illogical question, I then asked if he was sure he had the right bike?
At this point he looked at the rear number plate, said a few choice words and disappeared out of the door.
By this time the Charge Engineer was literally on the floor in a fit of laughter, until I pointed out that we had someone else’s bike in bits and if he came through the door we were in big trouble.
Just then the original miner pulled up outside on his correct bike, thanked us and disappeared into the sunset.
We carefully put the Honda back together and took it back to the bike sheds.
Luckily it’s owner must have been on the afternoon shift and was still working underground, or we might have had a visit from the police if he had been on the dayshift and reported it stolen, and my career with British Coal may have been shorter than it was.
In any case the owner had received a free wiring check even though he hadn’t requested one.
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John Grew sent this puzzle picture:  "Here is a nice ornament, but what was it used for?"  If you think you know the answers email to edgrew@virginmedia.com
I'll give the correct answer in the next chat. (As long as somebody sends me something to post.)
chat_images/pie funnel.jpeg


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Regards,
Eddy.