I thought the TG series replaced the CV series.
The .12 is less weight. THe .18 has more power, higher RPM.
I would go for the .12 TZ.
SPECIFICATIONS
OSMG2104
Displacement: 0.18 cu in (3.0 cc)
Bore: 0.629 in (16.0 mm)
Stroke: 0.590 in (15.0 mm)
RPM Range: 3,000-32,000
Output: 1.35 hp @ 28,000 rpm
Weight: 10.4 oz (296 g)
Includes: 203 air cleaner
Stock Numbers:
OSMG1986 .12 TG (P) w/12D Carb
OSMG1987 .12 TG-PX w/12D Carb
OSMG1988 .12 TG w/12E Carb
OSMG1989 .12 TG-X w/12E Carb
Displacement: 0.128 cu in (2.1 cc)
Bore: 0.543 in (13.8 mm)
Stroke: 0.551 in (14.0 mm)
Practical RPM Range: 5,000-30,000
Power Output: 0.7 ps @ 28,000 rpm
Weights: OSMG1986/7.45 oz (211.3 g); OSMG1987/8.82 oz (250 g); OSMG1988/7.5 oz (212.8 g); OSMG1989/8.87 oz (251.4 g)
Includes: 12E rotary or 12D slide-valve carb, #8 glow plug