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Starting problems

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Starting problems

Post  JohnB on Wed Jan 27, 2016 4:43 pm

Hi All, Hope you can give me advice / help. Yesterday I finished putting together my 1966 F.B. model 96 with the AMC 15T engine. I put fuel in and on the second kick it started and ran with no bother. Today No chance tried and tried but will not start!!!. Hope you can give me some direction. Thanks

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wont start

Post  piston 197 on Wed Jan 27, 2016 6:11 pm

Silly question, has the flywheel sheared the key ?, if the flywheel is not keyed to the shaft in the correct place it will not start
JH
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Starting..

Post  john87 on Wed Jan 27, 2016 6:52 pm

Think of this... If you have air, and you have fuel, and you have compression, and you have a spark, and the timing is right. Then it must run!!!

One of the above is missing

Check each, and you will find the problem!!

BUT, just remember, just because you have a spark OUTSIDE the cylinder, does not mean you have one in there..

Try this first.. Take out the plug. Heat up the end with a blowlamp or your gas cooker until the end "earth" electrode starts to get red. Get it as hot as you can on a cooker. Then, screw it in as quick as you can while still hot and try to start the bike. 95% certainty it will start first time..

[Has the carb flooded and filled the crankcases over night]

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Starting problems

Post  JohnB on Wed Jan 27, 2016 6:57 pm

I will check your advisory points John many thanks. I had petrol turned off overnight. Forgot to mention I did get the odd backfire if this has relevance?

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Re: Starting problems

Post  john87 on Wed Jan 27, 2016 7:44 pm

Backfire........ Plug fouled or VERY possibly timing slipped as has been mentioned. Bangs out of exhaust means it is too retarded, Thing tries to kick back and spits out of carb, too far advanced.

Check points have not just closed up..

Always try hot plug though, usually starts anything!!!!

john..

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Relevance

Post  piston 197 on Wed Jan 27, 2016 7:49 pm

Once again, take the flywheel off and make sure the KEY HAS NOT SHEARED, if you have not moved anything since it last ran OK it is the most likely, Odd backfire is exactly what I would expect.
JH
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starting problems

Post  JohnB on Wed Jan 27, 2016 8:39 pm

Let you know John. Thanks

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starting problems

Post  JohnB on Thu Jan 28, 2016 11:08 am

Yes John you are right. The Key is completely snapped off. How did this happen....what did I do wrong???.
Thanks

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well !

Post  piston 197 on Thu Jan 28, 2016 11:18 am

Could point out at this stage " I told you so" , but won't , if nothing else had changed, could not see it being anything else , "experts" eh !
JH
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Key

Post  john87 on Thu Jan 28, 2016 12:28 pm

Flywheel must not have been correctly fitted to the crank.... Either the tapers were damaged, or, they were not completely clean, and very importantly, oil free, when you fitted the flywheel.. The key is not there to provide a drive, it is merely a means of location. The drive is provided [and only provided] by means of friction between the two tapers, much like a morse taper drill in a drilling machine.

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Key function

Post  piston 197 on Thu Jan 28, 2016 3:47 pm

The key is there to make sure the flywheel is positioned in the correct place , admittedly the taper is the means of securing the flywheel , but with it in the wrong place the pulse point of the magnets will not correspond to the opening of the point, so yes you will get a spark of sorts without locating the flywheel with the key, but it will not be enough to start it,
So you do need both key and taper if the cam is not part of the flywheel, You get away with it on 8E type engines as the points cam is fixed to the flywheel and corresponds to the flux point of the magnets. Where the cam is a separate entity to the flywheel ( as in the AMC15T) you need a Key to locate flywheel correctly and a taper to fix the flywheel to the shaft so it does not shear the key, as has happened in this case, possibly damage to taper, possibly grit or dirt on taper, or possibly just not tightened up enough ??
JH
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flywheel

Post  john87 on Thu Jan 28, 2016 5:53 pm

Could well be not tight enough as you say, but tapers hold very well and should not need straining up tight.. Plenty of Villiers industrial engines, [no idea about the bikes] do not have any key at all, you just make sure the flywheel is in the right place and do it up..

Problem now, is, has the taper any damage, such as burrs alongside the keyway.. Time for a careful check for burrs and a check of the taper fit with the aid of marking blue.. I have lapped quite a few in, in the past, with fine valve grinding paste, and then solvol autosol metal polish. If the taper fits, just pushing it on by hand should make it stick. Push something into a morse or jacobs taper and try and get it out... Look at the way gauge blocks wring together.. Cleanliness with not a trace of oil is the trick.. I know assembling them dry sounds totally wrong, but assemble a machine taper with oil, and watch the tooling fall straight out!!

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tapers

Post  piston 197 on Thu Jan 28, 2016 6:15 pm

Yes cut my teeth on Morse ,Brown and Sharpe and Jacobs tapers, well conversant with them and understand the principle entirely. Also know that the industrial Villiers engines have no Key ( like the Villiers 10D,30C, 6E,7E,8E, etc.), but on these the points cam is riveted in place inside the flywheel to correspond with the pulse point of the poles of the flywheel, so you can always have the pulse point corresponding with the point opening at the correct timing,
On the AMC 15T the points opening can be timed separately to the flywheel position as the cam and points are external to the flywheel and not fixed to it. Regardless of how good the taper is, if the flywheel pulse is not timed to the opening of the points it will not go, unless perchance you have accidentally left the key out and fortunately have the flywheel in the right place, but unlikely.
This is why I was able to diagnose the fault as a broken Key and you were not, i.e you can have spark, points timing, fuel and compression and it still will not start if the magnetic pulse is incorrect !
I bought a Malaguti sports moped last year as a non runner, plenty of sparks, back firing, but not running, it had resisted the owner for 3 months, guess what the key was sheared in the flywheel, He had checked timing, point gap, timing of point opening, had put new rings and gaskets in it, cleaned the carb, but did not have a flywheel puller to remove the flywheel, as it was tight he assumed it was ok, There was 1/2 a key in the shaft and 1/2 the flywheel, the flywheel was tight, but about 15 degrees out of alignment, enough for it not to go. The correct puller and 15 minutes it was running like a dream.
Everyday is a school day and hopefully you have learned something new today
JH
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Taper

Post  MoscowFlyer on Thu Jan 28, 2016 8:05 pm

Here is a YouTube film on how to re-magnetize you flywheel, it's a school day John!! this guy puts loads grease on his taper. Be sure to read the comments below, about using a soft key. Mike

https://www.youtube.com/watch?v=vJTPQTrBNmk
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Mmmmmm interesting

Post  piston 197 on Thu Jan 28, 2016 8:18 pm

Mike, main problem with his magnetising procedure for our use is the Briggs/Stratton magnetron ignition only uses one magnet to trigger electronic ignition, cannot say it will work with multi pole flywheels like we use with a defined North and South pole, ( cannot say it won't work either, I must have been asleep at college when we covered this topic). What the thinking of putting grease on the taper is though eludes me, maybe he does not want it to rust in place ? In all engineering practice I was ever taught, tapers should be smooth ,clean and dry ???
Maybe I learnt something from this man with a view to magnetising and maybe I will continue with what experience has taught me  about tapers ?
JH
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Grease on taper

Post  john87 on Thu Jan 28, 2016 8:37 pm

Sorry folks, It is EXACTLY as john says in his post above.. The bloke in the video simply does not know what he is doing...

As John says; "In all engineering practice I was ever taught, tapers should be smooth ,clean and dry ???"

Completely exactly right.... Now, a bit of lubrication on the threads would be a good idea lest they pick up, but grease on tapers is a BIG BIG mistake.

As i said before, a key just provides location, the taper provides the drive.. Can hardly do that if it is greasy.

The bloke in the video can use any key he likes, when his taper slips and chews up the crank he will be one sorry bunny..

john..


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starting problems

Post  JohnB on Thu Jan 28, 2016 9:14 pm

Here's a challenging one guys. Do you know the key size? Plenty options on line but I guess the correct size is important Thanks

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woodruff keys

Post  john87 on Thu Jan 28, 2016 9:30 pm

Woodruff keys are identified either directly by size, say for example 3/32 x 1/2 OR by a number, say "304" The last two, in this case, "04" give the diameter the key would have if it was still a full circle, [near enough the actual length] in eighths of an inch, so the "04" bit would mean 1/2 inch, and the number or numbers in front give the thickness in thirty seconds of an inch,

Soooo, "304" would be 3/32 thick and half inch long!!

As for what size villiers use i have no idea!!

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Keys

Post  john87 on Thu Jan 28, 2016 9:32 pm

This might be useful to someone...

http://uk.rs-online.com/web/p/key-kits/0521816/

john...

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starting problems

Post  JohnB on Thu Jan 28, 2016 9:54 pm

Thanks John

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Keys

Post  john87 on Thu Jan 28, 2016 9:59 pm

Not saying they got the right sized in there mind, but it is a good selection!!!!

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Starting problems

Post  keith livingstone on Wed Feb 03, 2016 10:30 pm

Hello John B
Wisely of not I'm finally making a start to a seriously neglected Plover 95. i've been following your flywheel timing problems as there is much to learn. Maybe you could help me with a bit of advice too? Would you be able to provide details of the flywheel puller you used? My old villiers had the captive nut but this one needs one of the screw in extrractors. Diameter? RH thread? Many thanks. Keith
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Re: Starting problems

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