Need some help with Honda

Hi Wood Gassers,

I need a bit of help. No! Not psychiatric. That is a lost cause. Are any of you Honda small engine dealers or have Honda small engine OEM accounts? I called Honda North America tech support to try to get a GX200 solid model(STEP203) because I want to make a custom exhaust manifold to fit my latest generator project. Unfortunately they said that changing the manifold is modifying the engine and would therefore void the warranty. They wouldn’t give me the model which they say they have. Then they asked if I had a prototype and well…it all went down hill. I have a model from GrabCAD, but I would really like something which is almost guaranteed correct from the manufacturer. If any of you could get me a file I would appreciate it.

The big reason behind this is that I am trying to standardize on one very common engine. My inefficient house uses an average of 1.5kW so theoretically I should be able to get by on a 4kW derated to 2kW on wood excluding the heavy draw appliances like the dryer, water heater, and oven. This make a 4kW with a 196cc engine a perfect fit. It will also dramatically reduce the 9lb/hr standby fuel consumption of my old 389cc 6kW to something far more manageable. If I recover the exhaust heat so I don’t need the water heater or space heating, then off grid life could be pretty good on a minimal amount of fuel.

Anyways! Any help you guys could lend me would be appreciated. Once I get the parts proven out I will make an NPT inlet/exhaust connection kit available through my website.


Steve, not sure if this is what your looking for but there is a large clone market already out there.

I f the below link doesn’t work search ebay for honda clone or the web. Used in gocart racing.


Hi Stephen, I have been playing around with the 125 cc inverter/generators from harbor freight and generac. They are rated at 2000 w but on charcoal gas I am doing well to get 1300w from them. As you found out, once you alter anything on the factory made unit, the warranty is voided. Even running them on a fuel other than gasoline will void the warranty. I’ve come to the conclusion you just have to “Damn the torpedoes” and move on.
Gary in PA

Hey StephenA unfortunatly GaryG is correct that you will inevitibly just have to Damn the Torpedo’s full speed ahead with any new alternative fuels engine developements.
Been down that road now with a woodgassed Lister CS clone, Genrac V-twin, numerous B&S’s, Kubota 3 cyclinders. Now eyeballing the wifes new Kawasaki V-twin on her rider mower. (she only half trottles it, so she’d never know if later off warrantee I slipped in one of the older Kohler 17.5 hp singles for her 18hp!)
All my Hondas are the wet belt overhead cams. They will stay gasoline.
The better GX’s would be an excellent choice.
Once modified you’s have to be the supplier/warratee’er though. Not a bad risk as they are Hondas.
Steve Unruh

Hi Steve,

Warranty’s are the last thing on my mind. If I can’t control the input, I can’t guaranty the output other than materials and workmanship. I just wanted a good engine which also happens to be a very common one for spare parts.

Undeterred I just went for it with my Predator 212cc clone:

I took the exhaust manifold gasket off, scanned it, extracted the edges, and plasma cut a duplicate in 11ga steel. Then I made a jig to hold everything bolted in position. After welding I took a countersink and did a crude “porting” job.

The welding is not great, but I have a guy who does my production work. Hopefully the bolt holes are in the correct location. I know the angle is correct. Hopefully it fits when the 196cc clone gets here.