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

[911hillclimber]

Well, it won't start as things are.
Decided to have the magneto re-magnetised and a new condenser, points look fine.
The carb is squeeky clean and I have compression. The decompression valve is working, ie is closed when free, and I do have a good spark.

Timing seems right to the 'handbook' the timing simply is the points are 'just' separating when the piston is 3mm btdc and the timing marks are co-incident.
Plug is damp after rapid spinning over of the engine but it will not fire.

Even when I dribble neat petroil into the carb mouth there is nothing.

Villiers Services do not open until next week, so will tinker with the Terrot.

[911hillclimber]

Considerable progress!

I took the magneto to be re-magnetised, one pole was 'zero' flux and the other nearly as bad. Restored to full health and bought a new WIPAC condenser and a fresh plug for £30.87.
Learnt the owner lives in the next big village to me and his brother is a member of the same car club as me!

All re-fitted and timed, and nothing except a Fat Spark. Must be the carb then....

Put the carb body in the ultra sonic bath for 5 hours. There is one small drilling in the venturi jet that you can't poke through, so that might be the culprit I thought.
Oddly, bought a NOS carb body of UK Ebay for £13, awaiting delivery.

Just put the carb back together and all on the engine. Nothing.

Put a slug of near petroil down the plug hole and span it over for about 10 seconds and it fired, and it ran, and it throttled (quite well).

It even re-started on it's own without the neat fuel slug and I blipped it (odd phrase for a 50cc 1.5 bhp engine...) for a good time and tested tick over which killed it.

Decided to call it a day with a few thoughts.
1
I think the very effective silencer is very choked with carbon and stifling the engine,
2
I think the carb clean is 50% done, the NOS body should be the fix.
3
Time to order all the bits to get the bike road worthy.

[911hillclimber]

The NOS carb body arrived today, and it really is brand new, what a bargain for £13, this never (but now once) happens to me, just everyone else.

Dropped all the parts in, dropped the plug gap to 18 thou, I left it at 30... and the engine runs well.
Even will hold a steady tick over and responds to the idle screw, amazing.

Cannot find a BIMA silencer anywhere here or France, so will adapt a French design made for 60's Peugeot mopeds but will try to flush the current one out but cutting it in half, gutting the wadding and clean the body of carbon and oil. Then re-pack the small cylinder with steel wool and weld it tight.

I hope this will improve throttle response and reduce the smoke as the engine heats up.

This is so easy compared to the Terrot!

[Cortina]

Why not just burn it clean ..... lots and lots of heat ... with flame to ignite fumes .............(there WILL be a lot of smoke !!)

(silencer obviously)

save an awful lot of work.

[911hillclimber]

Good idea!
Most say burn the whole thing on another site...

I have washed a lot out with paraffin and left it to drain/'dry' for a week, but a burn-off sounds a good scheme.
Thanks as ever.

[911hillclimber]

Tried the burn-clean approach and got just some gentle smoke plumes as a result of 5 mines with the blow lamp into the silencer.
Going to open it right up and clean and weld/braze it al back together.

Lots of parts ordered and now arriving, white wall tyres/tubes etc today, cable sets etc very soon.
Also ordered a front and rear led light set, USB re-chargeable to go inside the 1940's cycle torch I bought for the BIMA years ago and a red light for the rear/plate.

Whole thing should be finished by the end of Jan I hope, just in time for the snow....

[neilbardsley]

This is going so much better than the Terrot!

Sent from my Redmi 7 using Tapatalk

[Cortina]

Sorry - when I said lots and lots of heat ... that's what I meant

you can't get lots and lots of heat from a blow lamp !!!

(you need big cylinders etc)

anyway ... have fun with plan b

[KS]

The other favourite way of unblocking two-stroke silencers used to be blocking one end and filling it with a caustic soda solution, leaving it overnight (or longer) and draining off.

Or petrol and a match.

[Kneeslider]

+1 for a really stout mixture of caustic soda granules. Just don't get it on your skin! Works great for cleaning out fuel tanks which have had fuel sat in them for 20 years too.

[911hillclimber]

Can you buy it from..where?
I would rather chemically clean than mechanically.
I have a small Oxy/Acet gas torch I could use.

Hope to get a good solid morning on the bike tomorrow, but have a new SKY box to set-up first thing.
Me and technology do not mix well...

Maybe some pics tomorrow!

Never done an 'oily-rag' re-commission before.
Sure is easier. Hard to resist wire brushing everything in sight.

[Kneeslider]

I bought the last lot of Sodium Hydroxide pellets from a good hardware shop. I think that you can buy 500g at a time, which will be more than enough. Like when mixing up acids, always add pellets to water, and not the other way around.

https://www.amazon.co.uk/Trade-Chemical ... 4Z7KMAAG8C

This should do nicely, but its probably possible to get it cheaper from a hardware shop.

[911hillclimber]

Thank you, but gave it a high-heat burn which cleared a lot and took ages to vent from the garage and me.

Still not sure, I decided to go open-heart and cut the top off. The metal was very very thin in places, irritating pin holes, so fresh 22 swg steel will cover it all. The burn had cleared a lot and at least it is dry in there now. Interesting silencer design inside:



Put the fresh tyres, tubes and tapes on the rims. The original hemp woven tapes were nackered, but interesting and original.



LED lights arrived today so can get on with that conversion, awaiting the cables and suchlike to arrive.

Good progress!

[911hillclimber]

All new cables on, inc the little de-compression cable to easy start/stop the engine.
Front brake blocks US I think, hope to find something I can adapt at Halfords tomorrow. The front brakes are like a modern push bike cantilever but with a 7mm dia pin, today, only 6mm are available, but no big issue.
Carb has a choke, but can't see how to activate it from the handle bars, must be missing something off the bike. More Google pictures needed.

Next up are the lights and the rear number plate with some hand painted numbers. I think most French reg numbers were hand painted in the 50's like Darren's 2CV's.

After that, it will be FINISHED!

Looking to sell both the BIMA and the Terrot, spring is not far away.
If I do another 2 wheeler it will have to be either another 70's Honda or something old, pre-war, but I have an RC model aeroplane on the building board, so might try that activity in 2020 along with the Lola and the old 911!

[911hillclimber]

All done!

Bike now ready to ride with all controls working and the 'period' number plate and lights on, and soon on a few sites for sale.
Thanks for all the help from everyone on this and the Terrot.