LCGB Forums

what are the pros & cons with lightened, mid weighted & standard weight flywheels, asking as im getting parts together for a TS1 engine build.
hope this makes sense.

A good question, and welcome to the forum.

In the simplest terms, a light flywheel will spin-up quicker, but a heavy flywheel will carry more momentum.

If you engine is designed to rev, then a light flywheel might be best, but if you have a low revving plodder, then a heavier item might work better. However, like everything two-stroke, there is a compromise to be had and when youwinson the swings, you might not get the go on the roundabouts.

Others might like to expand on this, with their own experiences.

Don't forget that lots of people suffer crank twisting and the heavier a flywheel you hang off the end of a crank, the more likely that you'll suffer the same fate. Rideability is one thing, reliability is another!

I'd love to run mid weight or heavier flywheels on my bigger cc motors so that I had a nicer tickover and flywheel momentum/inertia enough not to have to slip the clutch so much off the line and to enjoy a far more relaxed ride, however, I'd rather suffer the ride of a lighter flywheel for an increased chance of getting to my destination.

Unfortunately, Lambretta webs are very thin, in comparison to other high performance or high cc motors so there is less surface area to grip on the pressed crank pin, hence the frequency of twisting cranks with a heavy flywheel. Accurate interference fit of pin to web is essential and the addition of certain fitting compounds can help, however, many people turn to welding the webs to the pin as a drastic fix for the shortcoming of crank limitations. HOWEVER - Don't forget that flywheel weight has a dramatic influence on whether a crank will twist or not... reduce the flywheel weight and you reduce the chance of crank twisting.

Adam