Tuning Cylinder Kit ZT75N Stage 2 (75cc) - for Simson KR51/1 Swallow, SR4-2 Star, SR4-3 Sparrow, SR4-4 Hawk

Cylinder kit ZT75N Stage 2



Features:
- Original look cylinder with coated aluminum sleeve
- high-quality material for heat sink and sleeve
- improved heat dissipation through finely blasted surface and coated aluminum sleeve
- long durability approx. 10 TKm per piston, several oversizes available)
- Vmax 95-100 km/h
- approx. 11.5PS

Note:
The bore of the original engine housing must be expanded to 54 mm (engine housing reaming).
A BB crankshaft should be used.
The original clutch must be reinforced (conversion to 5-disc clutch KR51/1)
A tuning air filter must be used (air filter KR 51)
When installing a 21mm carburetor, please mount it directly to the cylinder and omit the original intake manifold.

Only Motul 800 2T Road Racing mixing oil may be used!

Use rubber buffers (10070259) for exhaust mounting! Possible breakage of the manifold thread with rigid mounting!

Scope of delivery:
- ZT75N cylinder (sleeve diameter 54mm)
- ZT75N cylinder head (eccentric)
- ZT 1-ring piston Ø49 mm including ring, pin & clips
- Carburetor flange gasket
- 2x cylinder base gasket
- 2x carburetor flange studs




For a long time, there were very few, more powerful cylinders for the KR51/1. This is due on the one hand to unfavorable channel guidance, and on the other hand, more powerful kits quickly reach the thermal load limit. With only 2 oversize pistons, the longevity of such gray cast iron cylinders was also limited.
The heat sink and the sleeve are made of high-quality aluminum casting. The sleeve is coated in a special process, making it extremely robust and optimal against wear.
The thermal conductivity is also significantly higher than with a cylinder variant with gray cast iron sleeve. In addition, the heat dissipation is further improved by a blasted, slightly rough surface.
Thus, the 2 core problems could already be eliminated by the use of new technologies.
The timing and channel cross-sections were designed for high torque from the speed cellar and a wide power band to harmonize perfectly with the 3-speed gearbox. This ensures that the drivability from the speed cellar is absolutely identical to our "old tuning cylinders". In addition, the performance in the middle and upper speed range could be significantly increased, resulting in a power band and power development that is otherwise unmatched in this class.