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Messages - The Artful Bodger

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1
I agree with Rex, kind of look forward to your saga! If the rest of the piston is right, ie. gudgeon pin size, correct shape to the wedge on top then it's easy. Just file the brass peg down and re-locate it, careful work with a hacksaw will cut it clean with the ring groove and making a new pin is easy as you have a lathe. Won't come out as the ring will hold it in and don't cost nothing!
 9 thou ring gap is a bit excessive? However it won't stop it running, don't stop now. Can't say I'm holding my breath but do look regularly to see your latest update.
  Colin

2
I would be very concerned with 5-10 thou clearance with the bush, if you can't check it yourself maybe take it to an engineering shop and have them see what's what. No mains bush should be near that much and you're asking a lot for an oil seal to seal with that much potential crank movement.
  I believe you mentioned you have a lathe, it's not a difficult job to turn up a new mains bush. If you have a lathe you must have a micrometer so you can check the crank for uneven wear and ovality, yourself. I made a tool post grinder for my lathe and ground my M/D crank myself, bought some lead bronze off eBay to make the new bushes (softer bronze as the shafts aren't super hard). The oil scrolls I will do freehand with a pencil die grinder. Worse case scenario it shouldn't cost a fortune for one main journal to be ground by a machine shop, just ask them to remove the bare minimum to clean it up and make the bush to suit.
  With the bush fitting the crank correctly an oil seal shouldn't be needed and the engine should be a lot smoother. Got to be worth getting everything right while the engine's down.
  Like the others I'm suspicious about those ports, old carbon can be like concrete. I would try attacking them with something serious until I was sure they were definitely solid metal.

Colin

3
Out of curiosity (that wot killed the cat) is there a felt seal on the plain bush side? If not it would rely on the bush / crank fit to be very good. My M/Debon (admittedly somewhat older than yours) has plain bushes both sides and no seals. Obviously a ball or roller bearing would need a seal hence the felt on that side.
  If there is no seal on the plain bush side it would suggest wear in the bush (and or the crank) so a new bush would be needed and if necessary the crank ground that side. If this is the case, and you feel the felt is a good fit, then by doing the bush the engine would still be standard and shouldn't require machining to fit other oil seals.
  Small Villiers engines have a bronze sealing ring which is pushed against a facing surface with a spring, I would assume your spring should be pushing a washer of some sort against the felt seal to keep it compressed against the crank. A simple but effective system which personally I would prefer to leave in place rather than fit a lipped seal, however your bike so your choice.
  If there is sufficient wear in the bronze bush even if you did fit a seal there's a possibility that the crank rattling a little in the bush could still cause a leak that side with a seal fitted.
  I had a bearing develop play on the timing side of one of my Banatams, I had to change it not due to vibration or noise but because oil / petrol was leaking out and onto the points. The seals were relatively new it was the small amount of play in the bearing allowing the crank to move and the seal to leak.
   As already mentioned, strange looking sight with the ports?

Colin

4
Re the condenser, with a battery coil it might be possible to run without a condenser for a very brief time but the points will burn almost straight away. With a magneto it probably won't work at all as the condenser sets up a resonance with the coil to produce a spark. My electrical knowledge is too limited to fully understand this resonance but I know it's there, and after much trial and error with Bantam magnetos trying different capacitors I know it's essential.
 As suggested a condenser can be externally mounted (to ground) with a wire run to the points. Or look at http://www.brightsparkmagnetos.com/easycap/index.htm they do a universal one.
  I bought some of these ceramic units through an electrical friend after looking at Bright sparks site and was very impressed something so small would do the same job. I fitted one on a friends Bantam and it was fine, unfortunately it didn't solve the issues with one of mine which required two condenser in the end to cure it.
 A bit of time spent browsing through their site, especially looking at the videos is very informative!
 By the by, throttle dampers were standard on about all British bikes to hold the throttle in a set position, I hate riding classics without them! Try indicating to make a right turn, without one every time you stick you arm out to make a right turn the bike slows down.
Colin

5
The battery / coil set up with a different plug lead and plug, completely does away with the magneto side of things except the points and condenser. If it doesn't run with this set up then taking the mag back to Villiers is a waste of time.
  So on the ignition front, using the battery coil, that only leaves the points and condenser to look at. You have fuel, either directly down the plug hole, or by the plug getting wet so it should go BANG.
  I don't know you so have no idea about your experience and knowledge, please don't think I'm being insulting to ask if the timing is 5 mm before TDC not 5 mm after TDC? although it does run on occasions which suggests otherwise. I have seen engines running after TDC and an exhaust manifold glowing like Rudolf's nose!
  Actually I do remember looking at two bikes for people in the past with a very similar problem as yours. One had a standard sized piston in a +40 bore, the other had no piston rings.  Both were bought as "should run with a little fettle-ling?? Although I thought you'd  had the engine apart? You do mention the compression, have you tried a compression tester? Remember with these the throttle must be wide open for a compression test. But............... I seem to remember you riding it a bit last year?

 Colin
 

6
You say that with the Villiers carb it started ran (after a fashion) for a bit then stopped with a wet plug. Cleaning the plug then putting petrol down the plug hole is a bad move, why put more petrol inside the engine when the plug came out wet, you're doubling the problem.
  Wet plug means too much fuel OR engine missing and not burning the fuel.  A wet plug really points against seal issues, how can fuel be getting up into the cylinder if the seals are leaking? A seal issue would mean no fuel is reaching the cylinder to fire, or it would be running very lean as air is getting sucked in. Either way not a wet plug.
  Try turning the petrol on from the tank and allowing the carb to fill, then turn the petrol off again. If (and when!) you get it started, as the level in the carb drops the engine should pick up and run smoother eventually revving right up as it runs out of fuel. If this doesn't happen then it's an ignition issue.

Colin

7
Many happy ones for tomorrow! At least the new one has pedal power, you'll be able to get somewhere engine or not. I think you need an award for persevere if nothing else, if you look at it as a learning curve you'll get a diploma by the time you're done!!
  If you do change the seals try to find some proper lipped seals rather than O rings, there's some pretty slim ones around. The lipped seals will seal better the more pressure that's behind them, O rings won't seal so well and won't take up as they wear.
  Keep one thing in mind though, the oil seals allow a vacuum to form in the crankcase to draw in fuel and air, they then allow pressure to build in the cases to push the fuel air mix via the transfer ports to the combustion area. Air will always be present in the combustion area if the piston's down so adding fuel via the plug hole you have a "good to go" situation in the combustion chamber. So it should fire, if everything else is correct, even if you take the carb off altogether.
  Even with leaky seals it should run to some degree (with a carb.) once it has started with fuel down the plug hole, hard starting is one sign of leaky seals but the other is the engine revving right up as it sucks air in around the seals so acting as if the carb slide is open. If it slow runs and dies as the throttle is shut off it isn't sucking in air around the seals.
  Not being there to see and experience exactly what's happening makes it difficult to guess what's going on. You can try soaking the felt seals with oil as this will both swell them and give more of a barrier to air getting sucked in and out.

Colin

8
I don't know how old you are but. In the old days every vehicle needed a particular starting technique, some liked half choke, some a couple of pumps on the throttle etc. Many old bikes are like this, my experience with the Bantams is they need to be flooded, well and truly flooded with the tickler, choke and a touch of throttle.
  You mention using full throttle to start, this is only of any use if the engine is flooded as it lets the maximum amount of air in at kick over. Normally the bare minimum of throttle is used for starting from cold as this acts as a choke in itself since the air passage is mostly blocked.
  A little throttle, maybe 1/8 of a turn of the twist grip will give higher than tick over revs. as an encouragement for the engine to start but not a great gulp of air that you'd get from a wide open throttle. As I said, full throttle is the way to go when flooded but not at any other time.
  By changing the carbs around, trying the battery coil and having about the same amount of luck?? I'm not saying you won't have seal problems, but petrol straight in the plug hole, now starting with about 1/4-1/2 throttle and no choke (as the combustion chamber is now rich) you have bypassed the involvement of the seals to get it started.
  Since the jetting of the carbs you have is an unknown for your particular engine you might well have running issues once it starts, however unless they are excessively out it shouldn't actually stop it from starting once you know it's foibles as to throttle position, choke position etc. that it wants to start with.
  Once again, a fast bump in second gear flies the engine over much faster than with a kick start and often overcomes any slight flooding issues, weak magneto spark etc.
Colin

 

9
Be interesting to see how tomorrow goes, from your post I'm assuming you fired it on the magneto? If so it seems a little playing with the mag gets it going for a spell. Be interesting to try it on the battery coil, if you haven't done so?
 All old two strokes will smoke like mad when started on choke and will take up to a 1/4 of a mile thrash up the road to clear themselves out. We were going to a show once and I made the mistake of following three Bantams from my house, being a sociable fella I made everyone a cuppa before we set off so the engines were cold needing choke to start. I couldn't even see the road for two stroke smoke following them, didn't do my lungs much good either!
  My research on my 1926 M/Debon is to run it on a 10 / 1 mix, I had an old Sea Gull outboard years ago and that also ran on a 10 / 1 mix. The reason for this amount of oil is a lack of oil seals, the thicker "brew" helps the plain bearings to seal. Might be a reason yours is supposed to be running oily?
Colin

10
One thing I forgot to mention in the last post was have you filled the crankcase with petrol again? Remember that every time you kick it over petrol is drawn in, if it doesn't fire then it's still kicking around in the engine and exhaust. A wet plug is the symptom of this so a new plug after much kicking over with the plug out will help.
  The advantage of a battery coil is a much fatter spark which will help. The one good thing with a 100cc two stroke is it's a lot easier on the leg than say a 600 single in a non start situation!

Colin

11
A drop of petrol down the plug hole eliminates the oil seals from the equation, at least as far as staring is concerned. The seals are only relevant to getting the petrol from the carb to the combustion chamber, put petrol in the combustion chamber and it should go bang. Only two other components are needed for the bang, compression and a spark at the correct time.
 Compression on your engine is down to two things, piston and rings being good or the head gasket. Usually you will hear a head gasket, or since you've had it running see some external sign on a leak. Older small two strokes often appear to have very little sign of compression compared to a 4 stroke. One thing which will alter the compression felt is having the carb totally closed, this restricts the air entering the engine therefore how much gets gathered on top of the piston to get compressed.
 Going the battery coil route is always a good test route, only one wire needs to be led into the magneto to the points. Battery pos. goes to the coil, battery neg goes to earth on the engine and the other low tension wire from the coil goes to the points and condenser. Since this doesn't involve the bikes electrics in any way either a 6 or 12 volt coil can be used, just use the relevant battery for the coil.
 Timing can be checked simply by turning the engine over from the flywheel with the coil in circuit and the plug will spark when the points start to open. If not you have a points / condenser issue. Perfect way to test how you've timed the engine as you'll get a spark you can see as you check the piston height BTDC.
  You must be able to get either a cheap coil (older car or bike) from a breakers or cheap off eBay. To test an old battery coil simply put a plug lead into it and a plug, earth the plug to the neg. of a battery and take a pos. and neg. wire from the battery to the low tension side of the coil. Fix one wire and touch the other to the terminal on and off, every time you take it off the spark plug will spark.
  This is all you're doing with it on the bike except the condenser will stop the points from getting burnt by reducing the current across the points face.
  If you intend to have another project bike in the future having a test coil sitting on the shelf ain't such a bad idea?

Colin

12
Not unusual for a piston port two stroke to spit a little fuel back through the carb. as the name suggests the piston acts as the valves and doesn't do a perfect job. Rotary or reed valves are more efficient and tend to prevent this.
  Many small engine two stroke carbs don't have a pilot circuit on the carbs, tick over was maintained by holding the throttle open a little. Killing the engine was by shutting the throttle off. If your carb doesn't have a throttle stop screw (a screw, usually with a spring on it,  going up at an angle to hold the throttle slide up) then it's not meant to tick over. D 1 Bantam carbs are like this, I've drilled and tapped one of mine so it now has a throttle stop screw.
  If your timing mark on the flywheel is near the firing point you will get a magnetic "surge" when playing with the flywheel. Don't think of a magneto generating a constant charge for the ignition circuit, it generates a momentary pulse of energy at the correct time for the coil to spark. This is when you will feel the magnetic pull on the flywheel. This is why I've mentioned the magnet's position being important, there is a very narrow segment of rotation where this pulse is generated strongly and it must coincide with the points starting to open.
  Pity you're not local (well to me) as I feel sure there's nothing too drastic wrong wrong, but small magneto two strokes can be very fussy and some experience with them goes a long way.

Colin

13
Sounding promising!
Colin

14
European and Other Bikes / Re: Lucer Ak3 grand sport
« on: March 22, 2018, 10:57:49 AM »
Hi Tony, as another member with a "no more french flea market tat" bike, welcome! Mini - Me seems a crusty sod, but actually will have a look around and offer suggestions for info etc. I think maybe he's got a soft centre hidden somewhere??
  I asked on this site hoping someone might have some experience with a bike like my latest project with about the same response as you got. But don't be put off. Two strokes are pretty simple things and most things can be overcome, but since your bike is running you don't have a problem............. as yet.
  A bike's a bike and I don't care where they come from as long as they make me smile, hopefully the same for you. Just enjoy it but remember the value will be limited on re-sale so watch your spending. When I bought mine I knew I would be making most everything I needed for it, both because it's French but also since it's from the '20's. I'd much rather own, ride and enjoy a French flat tanker than not have one at all, looking at British ones but not being able to justify the cost of owning one. In reality I love the look of mine and don't consider it a compromise. Enjoy yours!

Colin

15
Don't let it beat ya! Thinking logically................. You sorted out the points, re-timed it and it started right away?? Two things occur to me, 1 is the amount of fuel in the crankcase had evaporated to a point where it was ready to run? However my inclination would be to look at the points again. It was running, then running hard so........ Perhaps the points, timing have moved? or if there's a problem with the condenser it wouldn't take long for the points face to get burnt putting you straight back to square one as soon as the engine ran for a short while.
  As a point of interest which might or might not have any bearing. The wico pacy mag. on the D1 Bantams originally had a physically large condenser which you just can't buy anymore, the current ones for sale are about half the original size although they're rated the same. I kill condensers on one of my Bantams.
  My electrical knowledge is limited to say the least but I've formed a theory and a bit of trial and error seems to confirm this. When I first bought my GPO Bantam and got it running I came to the conclusion that it was dangerous to be on the road, at least with 6,2" and 15 stone of me on it. The performance was so slow, especially on any sort of incline, that I had a line of cars behind me all itching to get past. But I loved the look of the bike so decided to do some tuning on it to get a bit more "get up and go"
  Happy days! It's now capable of not being a hazard on the road and I've been using it for 6 years or so, even commuting to work on it some days. But............ The tuning means it revs much more freely and basically when I ride it there are only two throttle positions, on or off.
  My theory with killing condensers is since I'm almost constantly revving the nuts off it the HT coil is over generating and killing the condenser, remember the ones available are only half the size of the originals. I'm thinking they're kind of like a battery, think of an AA battery and a D battery. Both 1.5 volts but one with a much larger capacity, a re-chargeable D battery would stand a much higher input charge than the AA battery.
  A condenser is just two sheets of aluminium foil rolled around each other with an insulating sheet in between them, double the size of the condenser means double the size of the sheets of alli. therefore more able to absorb a higher current flow from the magneto. To test this theory I tried all kinds of different capacitors of the same value but ultimately they all failed. Then I tried two condensers and hey presto it's been fine ever since!
  I have a friend locally who's getting a bit old and doddery, he also has a D1 GPO Bantam which is more an ornament than a rider. Last year we took this and his B 175 down for MOT's booked one after the other. I had fitted a new condenser and points in the D! about a week before and apart from a quick blast up the road the MOT was the first run since fitting them.
  He rides very slowly and cautiously and stalled it at a busy roundabout and couldn't get it started. We swapped bikes and I got the D1 going first good kick, then thrashed it the last 4 miles to the MOT shop. I mean thrashed it! Since he was on the 175 he could keep up.
  About a mile from the shop it started missing and popping, we made it and got the MOT's but I had to take the points out and file them to get it home, about a mile from home it started missing and popping again.
  Basically the new points and condenser lasted about 5 miles. Did he stall it because the condenser was failing after a couple of miles? For me it started straight away and rode off fine for a few miles, or did my thrashing it cause the condenser to fail?
  Condensers are far more important for magneto's than battery coil ignition systems. Battery systems have the power from the battery to create a spark so the condenser is more to stop a fat spark at the points from burning the faces. Magneto's generate only a small amount of power to create a spark, there's a resonance between the coil and condenser which supplies a little more power to the coil to produce a better spark. So with a magneto the condenser is performing 2 tasks one as a spark booster and the other to stop the points face from burning.
  You had starting problems, changed the points face for nice new ones and the engine ran straight away. It revved it's nuts off and now it won't start, maybe I'm biased with the problems I've had with Bantam magnetos, specifically condensers, but........... Taking the points out again and examining the faces might give you a clue, there shouldn't be much going on with the points faces with only such a short running time. If there is anything then suspect the condenser.
  Unfortunately your swapping around with carbs. is further complicating things as none of them are really a known quantity, although you seem to have one which is basically working. However I can't help but think your starting issues are more ignition based.
  Sorry for once again writing a novel, I have too much time sitting around right now with the knee!

Colin

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