Honda with ST Head Questions

[Mikofox]

I'd like to know what the folks here think what would be the best way to couple a Honda engine to a ST Head.
I will have several ST sizes between 5.5 kW and 10 kW by the weekend using one 7.5 kW for the 12/2 Listeroid project.

Would a 13 HP GX390 be strong enough for a belt driven solution for the 5.5 kW or maybe even the 7.5 kW?

Is it possible to reduce the speed on a GX 620 to 1800 RPM to drive the head with a spider coupling? Or would the torque/engine performance suffer too much?

[mobile_bob]

personally i think the honda gas engines are currently the rolls royce of gas engines.
they seem to last forever, easy to start and dont require much maintenance.

i have a gx160 , 5.5 hp on a compressor that i have abused for the better part of 15 years, starts first pull
every time, has had one oil change, and an air cleaner when it plugged. ya i know,,,, bad boy bob!

i guess the barbers kid has the longest hair.

as for direct drive, you will suffer some significant hp decrease, i would expect not much over 7 hp at 1800 rpm, making the st5 head an armload for the engine.

perhaps you should consider a microgroove pulley drive, and run it up closer to 2500 rpm, probably get closer to 10 hp at that speed and run a st5 pretty well. or go full rpm 3000 or better to run the st 7.5

be a little noisey at full throttle, but it will handle the load much better in my opinion

bob g

[Mikofox]

Thanks for the reply. I looked at the performance curve for the Hondas and see the problem with reducing the RPM.
Just thought it would have been nice to reduce the RPM for noise and less stress/heat on the engine.