classic motorcycle forum

To post pictures on forums these days I do them through my own website, however my son does all my web site stuff for me and right now he's in Austria. So I'll try to describe a simple tool I made for timing engines from the piston.
  I used a length of welding rod (wire coat hanger etc. would be fine) , one end I hammered and filed to resemble a small screw diver but with a working edge sharp like a wood chisel.
  Around 3/4" from this chisel end I bent the wire with a sharp bend at a right angle so the flattened end is at a right angle to the wire. Basically an L with the chisel end being the shorter bit and around 8" on the long bit. Putting another piece of wire down the plug hole with the piston near enough at TDC I used this wire to measure from the top of the piston to around half way up the nearest cooling fin on the top of the head.
  Using this measurement I marked the long side of the L from the right angle bend and bent the wire 180 deg. totally back on itself so the wire is now like a double barrel shot gun with the 180 deg. bend at one end and the chisel end sticking out at a right angle.
  The idea is that the 180 deg. bend end sits on the piston crown, the chisel edge will be able to scratch a mark sideways on the cooling fin about half way up the fin. The excess long side of the wire is bent at a right angle well clear of the plug hole to act as a handle in use. Any excess can be cut off.
  You now put the tool in the plug hole with the chisel end resting against the fin and rock the flywheel back and forth until the highest point is observed, there are always a few degrees of crank turning at which the piston doesn't appear to move. Now use the chisel end to make a small but clear scratch on the fin. Remove the tool and now measure whatever the timing height is (5mm - 6mm whatever) below the TDC mark and make another scratch.
  On my Ariel the plug holes are angled outwards, on my Bantams they are angled backwards, but because you only have the thickness of the doubled wire, the plug holes have enough diameter for the tool to stand up vertically from the piston meaning any measurement is accurately the vertical piston movement.
   I always time engines by starting before TDC and turn the crank the until I see the points start to open, the old fag paper trick works pretty well. A gentle pull on a small strip of fag paper clamped between the points face, as soon as the paper starts to pull out you know the points are just opening. I then put the tool down the plug hole and see if the chisel edge is in line with the timing mark, if not then make an adjustment and try again.
  I time engines by turning the crank in the direction of travel rather than turning the engine backwards to the timing point so that any backlash in the timing gears, timing chain, advance-retard etc. is taken up in the same way it would be with the engine running. Not that this is an issue with your mag, just a handy way to learn to do it for when it does matter.
  This tool takes less than 5 mins. to make, every one of my classic bikes has two small scratches on a cooling fin and their own piece of wire in their tool box. As we all know pattern parts vary in quality greatly, so whenever I fit a new (or cleaned) set of points, as well as gaping the points I whip the plug out and check the timing as well. A slight difference in several parts of the points will alter the timing.
  Remember though, this times up the firing, it does not time the magnets to create the spark!
 
Colin
 

You've kind of shot yourself in the foot here? If the crankcase is flooded you have an excess of petrol, therefore putting more petrol down the plug hole is putting you back to square one. If you plug is wet when you take it out then putting extra fuel into the equation is a non starter (pun intended!).
 What you need to do is dry the engine out, hence the dozen kicks to blow the excess out of the plug hole. With the plug replaced you need to use no choke and a good twist of throttle to get extra air into the engine to offset the excess petrol. Putting a wet rag over the inlet is once again making things worse.
 As already suggested any plug will work as a short term replacement just to get it started, I've even used long reach plugs in a short reach head half screwed in just to get it banging.
  As already suggested using a battery coil will bypass 90% of the mag, the only parts still in use will be the points and condenser. Also a battery coil will give a much fatter spark at whatever speed the engine is turned over at.
  If I was looking at this I would start by removing the points and have a look at the faces, anything less than perfect I would clean the faces with an oil stone, the wipe them with de-greaser. If the points faces are anything but a silver colour I would look at either oil contamination or a faulty condenser. You describe poor oil seals hence the possible oil contamination, I just put new bearings in one of my Bantams as the timing side main had play in it and was allowing oil to foul the points. Every ride I got about 10 miles before it started missing and I had to clean the points, this was more than just a wipe with a rag as the oil caused the points faces to burn.
  If there's no oil there but the points faces are blue, purple or black (any slight discoloration) then the condenser has failed. Never assume that fitting a new condenser takes it out of the equation! I have a box of brand new in the packets condensers for various '70's - '80's cars and had to go through 6 before I found one that would hold a charge. They fail with age even still in their packages.
  By using a battery coil with the points cleaned any ignition issues will be bypassed, as has already been suggested. Even if the condenser is shot the engine will still run until the points face gets burned, this is not the case using a magneto coil. Magnetos work differently and there needs to be a resonance between the coil and condenser during the spark to produce enough energy for a good bang.
  A 6V or 12V coil wired independently from the bikes electrics (with clean points) will test the ignition for you. Use a suitable battery for the coil's voltage with the negative going to the engine as earth. The positive goes to one side of the coil and a wire from the other side of the coil goes to the points. For a short test it doesn't matter which way the positive and negative are wired to the coil.
  So the points will have the coil wire and the condenser connected to them, now you will have a good spark to try with. I have played around with Bantams for years now and have found several magneto problems they suffer from, several of these faults will give a good spark but the engine won't start. Two of these are; the main shaft of the crank has turned slightly in the crank web (this is very common on Bantams) so now when the ignition is timed up the magnets in the magneto are not in the correct position to produce the maximum generation of electrickery to create a spark from the coil. Kicking the bike over with the plug out gives a false impression of a good spark as the engine is spinning so fast with the plug out that the mag can generate a spark at the plug. As soon as the engine has compression and turns over much slower there is no spark inside the engine. This can sometimes be compensated for by altering the points gap to get the timing nearer the correct magnet position at the time of firing. There's other methods with a Bantam but I won't go into detail here.
  The second one is if the timing is too far advanced. An engine will, and indeed, wants to start with the timing retarded, still BTDC but more retarded than the best running position. Most small two strokes have fixed timing, ie. no manual or auto advance as the revs build up. This means the timing gets set in a compromise position.
  Too far advanced and they just won't start, however if you manage to get it going on a bump start you will notice the engine has more pull and top end. Too far retarded (without getting silly about it) and it will start really easily but lack power, go a little further with retarding it and you could heat seize it as it will run hot when reving.
  Flywheel magnetos can be fussy and everything wants to be "just right", some are fussier than others. They can be not quite "just right" and one day will seem to work fine and the next give nothing but trouble despite nothing being altered, bad starting is the main "show" of a not quite right magneto. Don't get me wrong I love magnetos, but I've had to spend a lot of time messing with them to learn their foibles! Battery coil ignition is a lot less fussy, I would be running it on my Bantams but the charging coils on a D1 don't produce enough electrickery to run a coil and the lights. I did fit later charging coils to one of them and this worked fine but I changed back to a magneto coil after several flat battery issues.
  Remember if you have magneto trouble the engine will become flooded since fuel is going in but not getting burnt, so you now have a double issue to sort out. Remember this if you try a battery coil as it might not work straight away due to the flooding. At least if it runs on a battery coil you will know where to start looking for your problem, I have a small 6V one I keep purely for mag. testing.
 If nothing else the length of this post might put you to sleep so you can wake up refreshed and ready to have another go?

Colin
 

A bit of a delay with the project, well two delays to be accurate. One is my usual problem with getting side tracked with other projects, one of which was currently taking up a bit of time. The other delay is breaking my knee in two places, 6 weeks of no weight allowed on my right leg of which I'm about half way through. Since this is the third operation on this knee over the years I'm actually obeying the doctors, getting kind of worried about the state it's getting into.
  I've puled the engine apart and it's about what I expected. Water has got into the bottom end and it's not a pretty sight. Typical of small two strokes it has a hardened con rod and crank pin with loose rollers, these are all very rust pitted. The main bearings (bronze) and crank are worn.
  I've made up a tool post grinder for my lathe and re-grinding the crank for the mains has gone well, I've bought some lead bronze to turn up the new bearings. I've had problems with lead bronze with main bearings in the past as it can expand quite a bit as it gets hot, with my Ariel the main bearing expanded in the alli. casing stretching the alli. I had to bore the casing out and make a new bearing with a steel sleeve which has been fine for around 6000 miles. Probably why BSA / Ariel made the bearings sleeved in the first place??
  Fortunately the M/Debon engine has steel sleeves which have stayed in the crankcases so happy days! The bearings are also pinned through the thrust face so I'm happy to use lead bronze for them.
  I have ground the crank pin down more than a couple of mil. and pressed on a bearing sleeve. I now will make a mild steel sleeve to press into the pitted con rod to take up the slight eccentric worn in the 'ole, this I will bore out to take a needle roller bearing. I have a bit of a concern with the bearing as the rollers are quite a bit narrower in width than the original, the overall width of the bearing is the same. However................ How hard am I going to ride this thing and how many miles am I going to do on it? I have a plan B should there be problems, but want to try the roller bearing first as it's cheap and simple.
  The bore and piston are in very good condition but the rings were seized in solid. After much soaking and gentle prodding I've got them out. If this was a 4 stroke I would make new ones straight away, but for now I'll run with the old ones. I have a Bantam which I've played with a little carb and porting wise, the piston slap has to be heard to be believed! Compared to other Bantams the compression is down but the bloody thing flies (well by 125 Bantam standards which ain't a lot!). The new small end is a simple turning  job, the gudgeon pin is good.
 This engine is so simple that pulling it apart in the future is a nothing job, first I want to see how the big end holds up. Whipping the barrel off to make new rings in the future if needed isn't a problem.
  Thanks for the suggestion to tig weld the barrel, I've had a tig for years but never tried cast iron with it, don't know why?? Anyway I had a play with a scrap Bantam barrel ( the missing fins on the M/D will be coming from this) and am kicking myself for not using tig for iron in the past!
  I haven't looked at the gearbox as yet, it selects all three gears but there's a lot of end float at the clutch as the gears are selected.
As soon as the leg's back in business I'll get stuck into it again, getting really bored not getting into my garage / workshop, but my wife's guarding the door armed with a cast iron frying pan with a mean look on her face!

Colin
 
 
 

Many thanks for taking the time to find the links, I had seen the barrel on eBay but it defeats the object of the exercise here. I'm a bit strange in so much as I love a challenge and make or repair as much as I can. My aim is to use every original part including screws, washers etc. as I can, repairing whatever along the way. I realise that many of the bits probably aren't 1926 originals, but they're on the bike as I got it so.....
  My foundry set up is all self designed and made, it actually caused a bit of a stir in the home foundry world and due to popular demand I ended up writing a book on it. All my powder coating equipment is home designed and home made, including the sand blasting, powder gun and baking oven. I'm presently building a lathe / mill to give me a larger capacity machine than my Myford super seven, but taking up less space. Not that I will get rid of the Myford once it's done.
  Point being here is, I like to make things! I then get great pleasure putting the things I make to good use making or fixing other things. If this was a Triumph or Norton of the same era I would try to keep it as original as possible, sourcing whatever parts needed to make it right.
  I'm not "disrespecting" this bike but don't feel the same need for perfect originality. I actually first got interested in it as a rolling frame for an engine I intend to build from scratch from a re-print of a 1906 book I have. But then figured there's enough there to get it going as is and build my engine as a direct "drop in" to replace the original engine occasionally. This way I can enjoy it as a stink wheel and then when I fancy it, drop in my own 4 stroke auto inlet lump. Gives me a two for one deal!
  Making the timing cover, primary cover and magneto, repairing the broken fins and inlet stub will cost me nothing and keep me amused in the bargain. It will make it "my bike" and I'll be proud to ride it, even more so with my own engine in it.

Colin

Hey guys lighten up a little? I do this for fun, not for political correctness or financial gain. I don't quite understand how any bike imported from any county can do any harm to anything?? I'm not the greatest fan of Harley's but don't get embarrassed when I'm out with friends who ride them. Like wise they don't shy away from me with embarrassment when I'm on one of my scooters. Sure we take the piss out of each other but we're still friends and still ride together.
  Oh I guess I should mention before political correctness bans me from mentioning scooters on a classic bike forum, I ride them because the arthritis in my left hand allows me only limited clutch operating time, since I ride two wheels 7 days a week all year round I needed something to give my hand a break. Got to say though............ I like them if I need to get somewhere rather than being just out for a ride.
 I bought the bike from a guy bringing them over en-mass, since I don't speak a word of French this was (for me) the easiest route. But  I had no intention to buy a French bike, German bike, Eskimo bike or whatever, I was just looking for a bit of fun.
 I do my own casting, welding, machining, sandblasting, plating, painting, powder coating etc. so re-build costs tend to be pretty low. I'm aiming to have this on the road for between £1500-£1800 which includes the purchase price. By my reckoning that ain't too much for a 1926 bit of fun?
  Thank you to all those offering advice and encouragement, I haven't taken any pictures so far but will try to post the ones from the eBay listing. As I progress I'll try to keep this thread updated with more photos etc.
  Had fun the last couple of days trying to get the fork link pins out, this has no bushes in the forks with the pins running directly in the castings, or in my case rusted firmly in the castings. A good soak in hydrachloric acid shifted all the surface rust but didn't penetrate at all, an overnight soak with penetrating oil then a generous application of heat didn't help either. So have resorted to drilling them out which has gone well, a rummage in the "stock pile" (also know as junk corner) has produced some suitable "stock" to turn the new pins up from. I have had to order a suitable sized reamer to ream the castings out back to clean before I can make the pins to suit.
  I was more concerned with sorting the forks than any other aspect of the bike as I figured parts would be scarce (confirmed by your good selves) if anything broke, but happy days they'll be fine.

Colin
  I like a relaxed, easy life so don't expect

Hi All, just went mad and bought what I believe is a 1926 Magnat Debon 250. I know nothing about these so am wondering if anyone out there has something similar or some experience with these beasties?
 It's been sitting in a French barn for many years and is about 80% complete, fortunately although very rusty the frame and all the tin ware is sound.
  Hopefully I can touch base with someone with some knowledge please??

 Colin