Flywheel with no timing marks at all

[Nic]

I'm hoping someone can help: I bought a Lambretta electronic flywheel from TSR in Wales.

When it arrived the flywheel had no timing marks on it at all. I know you can use a piston stop to find TDC. But how do you set it up up relative to the pick-up box if the flywheel doesn't have any markings on it to align with the stator? Is it a case of continuous trial and error or is there a simpler way, apart from sending the flipping thing back?

[Sticky]

It's pretty simple if you are going to strobe. You can make an arbitrary mark on the flywheel and find TDC relative to that and mark the mag housing. Then mark your chosen firing point on the mag and strobe. If it doesn't align then move stator and re-strobe.

Here's a little video I made earlier that may help:

https://www.youtube.com/watch?v=o0yGOyyzcfg

[rossclark]

I wouldn't trust any marks on any non Ducati flywheel. Even then you should strobe to confirm

[missing lynx]

I always put my own marks on then strobe it

[Warkton Tornado No.1]

The point that Sticky, or anybody that has an understanding of ignition timing, is making is this:

A mark may be made on the flywheel in line with any convenient mark on the magneto housing to denote Top Dead Centre (TDC)

Once that has been established, an additional mark can then be made @ the desired timing Before Top Dead Centre (BTDC)also on the magneto housing. That is called the firing point. It will be Anti-ClockWise (ACW) on the magneto housing.

There are a number of ways that the firing point is measured out but the preferred method is to use a Dial Test Indicator (DTI) in the case of 'head of or with a central spark plug. Most Readers will therefore use a degree disc or linear measurement.

Once established, it’s a case of running the motor with a strobe to check alignment of the firing point mark with the mark on the flywheel & adjusting the stator to suit.

[isthmus]

hi,there should b an arrow on outer front edge of the fly,si

[isthmus]

also there should be 2 lines that match 2 lines on the stator k2 pick-up on one of the windows,good luck si

[CHRIS in MARGATE]

Some flywheels have the 2 marks but you should really only use as a basic set up to fire it up and then check the correct timing with a strobe.
I detect that you are a little unsure but if you follow all the advice and my response on the other forum you will be ok. Do not set up an electronic ignition without a strobe.
You can buy a strobe for as little as £15 on ebay. You connect the black and red power leads to a battery and you clip the sensor over the HT lead next to the plug cap.
Use typpex or white paint and paint a thin line on the front face of the flywheel right up to the edge. Paint another small white line at your timing setting eg: 19 degrees before TDC on the magneto flange. This will be approx 1 and 1/8 inches to the left of the TDC mark. Use a timing disc or print one for free from the internet and lay this over the taper of the crankshaft with the flywheel off. Zero the disc to your TDC mark and count to the left your required firing point. Opinions will vary but that's another debate. Let's say it's 19 degrees. This is where you scribe a permanent mark on the mag housing and subsequently paint white.
Reassemble and torque the flywheel and start the engine. Hold it at a steady tickover and then point the strobe light at the mag housing. The white lines will appear stationary and show you if your timing is either too far advanced; spot on; or retarded.
If the 2 white lines of the flywheel and the mag housing do not line up then cut the engine and rotate the stator plate accordingly.