standard points ignition question

[Supereibar]

Evening peeps. Just end up the rebuilt of a TV175 bog standard engine. I set the timing at 19º as the points ignition closing gap. Tried kicking the engine and the cables off the stator sparked fine. Refited the engine on the scooter. Tried to kick it over and I get a very mild spark. Put some petrol on the tank, kick it over... scooter doesn't start... Tried again fitting the petrol directly into the spark plug hole... nothing. I am sure the problem isn't a carburation problem. Im obviously finding myself with an electrical issue here. My question is, does setting the engine's firing point at 19º will upset the starting at all at a points setup? If so would you reccomend something closer to the original 23º.. (Bristolmod I know you run all your engines on points, in fact you taught me how to set up a points ignition system... You may be able to throw some light here...)

Cheers,

Jaime

[sean brady scooters]

it should be points opening.........at your desired timing....not closing...

[Supereibar]

back to sticky now... will post results. Many thanks Sean

[vince]

Hi mate. with the flywheel travelling in the right direction ( clockwise) the only thing that can happen is for the points to open as there is a cam the points lift on ! It is always better to check the ignition timing with the flywheel travelling in that direction . If the bike has not run for many years maybe the flywheel magnetism needs to be boosted. this can cause a weak or no spark situation.
Most scooters seem to run with the stator in almost any posistion but setting it in the correct place has to be favourite.

[bristolmod]

Jaime

as indicated above, a Lambretta points system is fairly forgiving inasmuch as it will run over a wide range of timing ranges (probably 25 to 16 BTDC)

Is your gap correct at c15 thou (Imperial NOT metric which you probably use on the Continent)

I start by setting the stator in the mid position on the slots, and rotate the flywheel until the points are fully open then set the gap at 15 thou- be careful; when you retighten the little screw it sometimes pulls the gap closer.

This should allow the engine to run- you can retime accurately later with a free timing disc from the net.

Are you using a new plug correctly gapped?

Is the flywheel OK re magnetism?

Is the coil correctly cabled (O and 15 correct way round?)

Let me know

Chris

[J1MS]

When you have tried all of the above, it should run. If its still not running then check the points for resistance when closed as dirty points will give a spark at the green wire, but will not normally produce a spark at the plug.

[dapper]

Check for dry joints at all soldered parts and try a different capacitor (condenser). Are they brand new points, as sometimes they come with a film on the contact points which needs removing with a fine piece of emery/wet & dry. Have you tested that the points open and close properly with a tester? Sometimes the insulation washers that seperate one contact from the other can be assembled wrongly and short out.

I had an instance where I couldn't get the scoot to start. Checked I was getting what I thought was a good spark from plug. Had me baffled for a while. Eventually took the flywheel off and the points had broken and one contact was sticking to one of the flywheel magnets. Despite this I was getting what appeared to be a good spark at the spark plug.