RUMCars Forum

General Category => Off Topic Lounge => Topic started by: Jonathan Poll on January 27, 2013, 01:53:27 PM

Title: Villiers 100
Post by: Jonathan Poll on January 27, 2013, 01:53:27 PM
Hello all,

  As you may have seen, a while back I got a Peugeot 98u motorbike.

It's got a french built (under license obviously) 100cc Villiers engine.

The engine turns really well (suprisingly, because the bike was rotting away under tiles and planks!

VERY good compression, but VERY weak spark... If I put the HT lead next to the frame and kick it over, I can't get a spark bigger than 2mm... (HT lead is fine).

Points are fine, work perfectly (tested on multimeter).

Does anyone have any idea what the problem could be? I'm thinking it could be the coil. I don't think the condensor is the problem, if I'm right a faulty condensor makes sparks at the points? I cant see any sparks at the points when the engine turns.

Not sure how strong the magnets need to be on the flywheel, but they seem strong when testing with a piece of metal.

If the prolbme is the coil, does anyone have one spare? I'm offering 15£ including postage to france. Price seems fair to me, you decide.

Title: Re: Villiers 100
Post by: richard on January 27, 2013, 06:14:11 PM
could this french site help you at all with your various machines ?
the small ads look interesting i thought . re your coil i suggest villiers services , wolverhampton - it would be guaranteed and not dear - second hand coils possibly not a secure bet unless a gift  ;) they will take an email enquiry - the engine would be the 98cc junior i think possibly 1F , but tell them what you have . French villiers up to 1959 is this correct for you ?
Title: Re: Villiers 100
Post by: Jonathan Poll on January 27, 2013, 07:33:51 PM
Cant find your french advert? I foud a 200cc motor, but thats it :S

I will contact villiers services!

Thanks, JP
Title: Re: Villiers 100
Post by: Bob Purton on January 27, 2013, 07:55:44 PM
I had a Sachs 50cc motor once that had a very week spark, just cleaning the inside of the flywheel and the metal parts of the coill magnets back to bright metal made a large diference. Have you got the flywheel off yet?
Title: Re: Villiers 100
Post by: Jonathan Poll on January 27, 2013, 07:57:38 PM
I have had the flywheel off, many times in fact! I think I done that, but I could always do it again, worth a go if it could get it back running "for free"!

May give it a go wednesday afternoon.

Title: Re: Villiers 100
Post by: richard on January 27, 2013, 08:08:44 PM
i was meaning the site in general not specifically for your querie . i thought you may be interested in it being for french two wheelers . the "petite annonces" seemed to be general small ads i meant it to be of help finding bits . got to be of more help than us  ;) we being RUM , microcars not mopeds
Title: Re: Villiers 100
Post by: Rusty Chrome (Malcolm Parker) on January 28, 2013, 12:25:41 AM
The condenser is to stop sparking at the points, but a faulty or damp condensor can give a weak spark without any notable sparking at the points. Heres some links about testing condensers ( (

The magnets are unlikely to be a problem, much more likely is poor earthing or faulty insulation
Title: Re: Villiers 100
Post by: Jonathan Poll on January 28, 2013, 07:37:25 AM
Well it does look a good site rich, got a couple of nice New Maps on there!

Thats a good idea to test the condensor, I'll give it a go!

I forgot to say that the small wire from my coil (I think the wire goes on the condensor?) is in bad condition. The plastic outer has cracked, and its very "flimsy". I patched it up with electric tape, in case it shroted out or something, but still no bewtter. You cant replace it either :(
Title: Re: Villiers 100
Post by: Big Al on January 28, 2013, 12:49:47 PM
After a serious clean out to make sure sectional parts are such, insulation is such and the parts are clean it can be very frustrating to find no change. The points should spark well without the condensers. Condensers are notoriously hard to test but for a brief time you can do without. It will burn the points out eventually. Fortunately condensers have changed little in operation so a botch to a later one of the same value will work.

Coil is slightly easier to check but more difficult to replace as the values and specs do vary more. If you have a similar set up on a runner swapping each part should identify roughly where the prob is. If you can fix it is another matter. Some bike coils can be opened up. Sealed ones like Microcars are not fixable, They can die slowly, the black blob of death being the first notification as they start to overheat melting the insulation of the coils. Same thing happens to the little 'uns but it can more difficult to see. A hot coil in a live inert circuit is always suggestive of a poor coil. Clearly a mag does not do this but you can force the issue with a suitable battery. I would shove it through up to a 30 amp fuse in case there is a short. Guess it is less for 6V. The fuse should die first.