1952 Peugeot BIMA Moped re-build.....

[911hillclimber]

Thought it was time to move on from the Terrot saga so starting another less fraught, easier, less stressful less urgent rebuild of another French folly, my 1952 Peugeot BIMA 'moped'.

Bought this about 4 years ago and registered it in the UK then bought the Terrot to do first, so this has come out of the shed at the bottom of the garden for an inspection of what it actually might mean.
My current intent is to do a re-commission, an oily rag rebuild in the loosest of terms, but to get it working reliably and safely but keeping all the originality I can.
Never tried to do this before, and the urge to strip, restore, painful rebuild to original 'new' status is hard to keep in mind.

It owes me £600 already. It is worth about the same, tops, so as ever a loss making machine but should be interesting as a mini garage-in-the-winter project.
It was made when I was born, and has a few negatives, much like it's fragile owner...

Good bits:
Engine is nice and free, compression, and the de-compression valve is all free. I hope to leave the engine intact. (49cc 2 stoke)
Carb is in great condition, just full of dried French fuel and missing it's filter cover, £40 off ebay.Fr
It is the early chain drive so my fingers are crossed (notorious for snapping) but a good clean and maybe a new one.
Magneto looks great, coil is old French and not original (I think), need to check for a spark.

All metalwork is clean, rust free but some cosmetic surface rust all over, but was light cream and royal blue. Decals all distressed by time alone.
Saddle needs some delicate re-stitching, might send this to a DDK'r to rescue.

Over time the bike has been worked on and some original fasteners are lost. Can you buy 'distressed' steel fasteners? (ie M4 and M5)

Bad bits?
Not many.
The parts that are perished are the tyres, tubes, brake shoes, control cables, wrong fuel tank cap and a cracked rear reflector.

Budget is £500.

The way it all worked is a bit 'demanding' in that you can/have to pedal the bike like and push bike. The engine is engaged with the exhaust valve open (controlled by twist grip) by pulling an over-centre cam that presses a gritted roller to the tread of the rear tyre.
Still pedalling hard, you close the de-compression valve and open the throttle and the engine then runs and takes over.
Speed is controlled by twist grip and the engine will tick over so slowly you only need to kill it at very near zero mph.

A challenge then..

Here we are: Engine covers off

[KS]

Good luck with this one! Wish I'd kept my Monet & Goyon now...

[911hillclimber]

These light bikes are a real charm to work on, so light and miniature.
Space is the usual problem, storing them still needs a lot of room, I have a good sized shed, the garage is full of Porsche projects that all work!

I hope this will be an easy one too!

[willbrown]

such a neat compact design. a great winter project - looking forward to the updates.

[911hillclimber]

Tasks before Xmas is to get all the prep done on the 49cc Wonder.

The carb came off easy, I'm a bit suspicious of the carb, looks too 'new' compared to the rest of the bike.
However, 24 hour soak of the parts in paraffin after a strip got the crud off well and with all the parts off/out I gave the drillings a good poking through.
Main jet was blocked solid and also the main 'feed' port.
All freed of the blockage thanks to my set of BOC gas welding nozzle cleaners bought in '72 when I built my first hot rod!

The carb does not have a jet needle and is very small, just 10mm choke diameter, but all cleaned nicely.
Have to make 3 paper gaskets and it can go back together.
The carb has no name on it but I think it is a Gurtner.

Next came the coil. It was loosed in place by one odd screw, somebody has been at this bike recently, I think the Brit I bought it from who used to buy/import French 'barn-finds'.

It is the original, made by MOREL who I think made the magnetos for these mopeds too. The mag has no name on it.
Have to find out which wire goes where yet.

Got a plug and have a silencer, original with a good array of small corrosion holes in it at one end so some brazing coming up.

With some fresh petrol I should be ready to try to start it with a good 240v pistol drill on the flywheel nut.

Good fun!

[jjeffries]

Glutton for punishment!

[911hillclimber]

Nah, this one will be very easy, I've barely touched it so no mistakes so far...

Plan is to simply get it going, safe and ridable, and to stay in the £500 budget.
The last bit is the hardest.

My Xmas pressie will be a distraction, esp if the weather goes cold.

https://www.youtube.com/watch?v=X_5r3HfqIVI

[KS]

There's this, too...
https://youtu.be/96jr0Ff6Gt8

[911hillclimber]

Yes, seen that one.
That is a full rebuild of the frame job, add £500 for sand blast, paint and chrome, and 3 months lost.
Trying to avoid that, this will be a rat rod approach, much ask loath the style. Hard to find the time to get trusty stuck in ATM

[911hillclimber]

Three steps forward, but no prize today.

Have a spark, not exactly a BIG spark, nothing like the Terrot's, but a stream of sparks when you spin the engine over with the pistol drill (bliss).
Have fuel in the carb, and the plug is only 'just' wet, but fuel on the plug.
Have nice compression...
But, it won't even whisper a fire at all.

Can't help but feel the spark timing is wrong or the spark is too weak in the chamber to fire. Have dosed the attempts with Easy-Start at times but nothing.

There are timing marks on the engine (one) and one on the edge of the flywheel. If you align these marks the access to the points is perfect, so I guess this is where you set the points gap (0.4mm ) as you can set them easy.

However...there is nothing then to set the flywheel to the crank to allow the spark to go at about 3mm BTDC.

Need a bit of help please if anyone can guide me.

[Cortina]

Not sure I understand the problem exactly
a) set the points gap - this (in my experience) is never done with engine in an exact position . It's simply a maximum gap - where that occurs is slightly irrelevant. Clearly access to the points is kind of handy !!

b) is the flywheel not keyed to the crank ? (I guess it would work on a taper only , but that would be unusual ??)

c) point at which the points just start to open is the key "dimension" ... but you know all that anyway - clearly this need to be at approximately correct moment ... these types of engine are not usually too fussy on exactness , but it clearly needs to be roughly right.
How is timing adjusted ? - normal method would be by rotation of the backplate, points are mounted on . If not , then adjustment of flywheel on taper (easier said than done) - offset key ?? ... I would not think so.

dial gauge down plug hole - directly or indirectly - to find out where TDC is and what marks tie up with what ? (straw and fingers probably good enough to give you a feel for it)

I suspect none of this is any help ... just keep it simple , these are not complex machines ...............

(.PS. no guesses , no assuming !!)

[911hillclimber]

All good questions!
These machines are very simple/crude.
Fortunately, another enthusiast on Classic Motorcycle Forum has found me the English version of the Owners Manual that gives all the timing details.

Hope to follow the lot tomorrow and it will fire, but the spark is very weak indeed, so the mag might need re-magnetising.

The flywheel has no keyway, it is all locked in place by the friction of the taper on the crank, the other bike was the same.

This is the Owner's Manual:

http://comet-restorations.uk/gallery/bi ... s_1956.pdf

[911hillclimber]

Tried several things, but all to no avail.
Checked the timing as per the English Instructions, seems I had it right.
Points 'just' opening when the timing marks are aligned which is 3mm btdc.

Reversed the coil connections to yesterday, no difference, still have a string of sparks when turning the engine over at about 1000 rpm (power drill)
Stripped the carb again, poked through every hole I can find, all clear. Float bowl is full, fuel flows from the tank.

Put some fuel directly into the chamber and tried, nothing, and also then put a slug of fuel into the mouth of the carb, nothing.

The person before me wired a new capacitor in but outside of the mag, it should be inside, but this should be changed (if I had one) just in case..
Need to find out how to check a 6v cap.

Me and French 2 strokes just don't mix well.

[KAS.750]

Ever thought of stamp collecting

[911hillclimber]

Far too difficult...
Imagine trying to find those elusive rare ones, costing too much and never being sure it is right...
Certain parallels!