Fuel Efficiency or Speed?

[MotoRandy123]

The Yager makes max torque at 6500 RPM's and max HP at 8000.

The best I can tell the variator is tuned to 7200 RPM (right in between).

Max fuel efficiency is at max torque or 6500 RPM.

Max power is at max HP or 8000 RPM.

The stock roller weights are 20x15 16.5 g.

So to get max fuel efficiency go down 0.5 - 1.0 gm or to get max power
go up 0.5 to 1.0 gm. If you go too far you will need to tune your contra spring.
Slipping going uphill means it's too weak, not achieving max speed means it's
too strong. 

[Yager200i]

I believe you have that backwards. To lower engine speed to the max torque RPM, you'd increase roller weight. To raise engine speed to max HP RPM, you'd decrease roller weight.

And the German website with the parts list for the Yager shows the roller weight to be 17.5 grams.

I'm going to order 20 gram Dr. Pulley slider weights, because I want lower RPMs for in-town riding, hoping to increase fuel efficiency a bit. When installing slider weights instead of roller weights, you have to do a bit of conversion... for 50 cc engines, increase the slider weight about 0.5 grams over the original roller weight. For 50 to 150 cc, increase by about 1 gram. For 150 to 300 cc, increase by 2 grams.

I'll let you know how it goes after I get them installed.