Gx50 china girl hybrid?


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7:45 PM
Apr 9, 2018
United States
Ever wish for a 4 stroke cg with the manual clutch and a 4 stroke that mounts like a cg this guy is taking the first step. He also wants to build a vtwin with 2 gx50 top ends. He bought a few gx50 clones to experiment with. One thing I disagree with is he wants the small bevel gear to be a chain drive to the clutch instead of gears and he talks about getting rid of the bearing in the clutch. Both are dumb ideas. Overall it's an awesome idea and you solve many problems by converting to a 4 stroke no mixing gas longer engine life, lower noise and you save money on oil costs since 2 strokes require oil every tank but the oil in the crankcase can be run for much longer. Damien I know you don't like this guy but keep an open mind.

This is not coming to market. The cost is just way too high. His plan to finance the material and opportunity cost of the machine time is to crowd fund it through his own website.

Based on his custom piaggio bottom end its gonna be 600 dollars before you get the stock gx50 to put on top. And that's if he uses the stock china doll reduction. What he wants to do with 35 chain is more expensive.

It would be a 900$ 2 horse honda aimed at a market split between guys who want it as cheap as can be and guys who want a hayabusa with pedals.

I have been keeping up with this since the start: the problem he is trying to solve on the gx50 is the bulkiness the final package. This problem can be solved by mounting it on a rear rack. A rack rated for the weight does not cost that much, and that's only if you go chain drive instead of friction.

He has some contacts in china but they're not gonna touch it for the same reason really any small engine manufacturer in china hasn't already done a 4 stroke china doll: the market is too small and the final price will be too high.

Putting aside the feasibility of the product, this guy can only really keep up with the bids that pay his bills, let alone the motorized bike side business.

I'm sure he means well and is nice enough in passing, but he's not "cooking" with this one.
Yeah, the current china dolls are already too expensive once you get into engines that aren't completely dog poo.

Considering you can get a Honda GX200 clone for $115.

We are a tiny little ripple in the pool, E-bikes made the big splash so if someone suggests something cool, manufacturers might listen.
It is worth watching his thought process change through this last month but here's his "thesis" on the gx50 based custom engines he wants to build. Mind the kitty, he's taking it to the vet.

This one has the complete drawing for the V twin 2 speed. I had suggested he check out Chris rather b welding's two speed for design cues the video before this and I like to think I helped.

I like the core "philosophy" behind it: small, light cheap and useful. I can image his will be small and light, maybe even useful, but certainly not cheap.

The design of the china doll is solid, and as they come its 3 out of 4 those design goals achieved. It just needs to better quality control standards to be truly useful.

Even if a small engine plant does pick it up, unless the final unit cost is about the same as the existing four stroke kits, the facebook groups are just gonna say "buy a phantom 85 and cranbrook" and that'll be that.
It's a neat idea, but just not doable in an affordable way. It's a cool concept and cool to see someone doing it, but in all reality very few could afford it.
The advantage of a gx50 top end over a 142f top end is the case meshes together flat instead of the 142f that is slanted. I wonder if using an oil pump instead of the oil mister would save space on the cg conversion.
Those mist generators are in the same spot as an oil slinger. There is no space savings.

About 6 minutes in he says he wants to put a sprocket between the bearing and the positive drive pulley for the cam, is that what you mean on space savings?


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Those mist generators are in the same spot as an oil slinger. There is no space savings.

About 6 minutes in he says he wants to put a sprocket between the bearing and the positive drive pulley for the cam, is that what you mean on space savings?
One aspect is the chain but theres no reason not to use just gears like on a cg. I meant the oil pump of say a z50 honda or similar could be fitted. On the z50 there's no oil slinger or mister but it has a pump.

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And actually the mister is not saving room since instead of being directly attached to the rod it's further down the crank in a separate oil compartment area. By deleting the °360 mister you could just add a huasheng rod or some other type of rod with its own dipper and figure out the rest or use a pump. As you can see in the 2nd picture that is a steel with needle bearing rod for a gxh50 or 142f


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Alright I was wrong. Problem with gears is machining cost. This gear is almost thirty dollars https://www.grainger.com/product/KHK-GEARS-Spur-Gear-Module-m-1-792YN3

And a similarly sized sprocket is ten.

And the disparity is worse if you want a helical gear like the china doll uses. https://www.grainger.com/product/KHK-GEARS-Ground-Helical-Gear-Left-Hand-793A55

Hell, 90 of the cost has got to be the clutch and reduction on these little two strokes.