Unorthodox Head Swap GX200

karl

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Dun thunk this up at work, watcha think? :p
 

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mckutzy

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Well.. You certainly thought outside the box..... But hey, if the bolts match... and if it runs....
Cool....
An odd ball carb setup though....

IS that a tec or briggs head???

And did you hit a bolder to break that crank???
 

karl

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Well.. You certainly thought outside the box..... But hey, if the bolts match... and if it runs....
Cool....
An odd ball carb setup though....

IS that a tec or briggs head???

And did you hit a bolder to break that crank???


She'll be right

Yeah, might stick a pumper on it.

The motor I took the head off is a china copy of a honda GXV motor, the vertical shaft version of the GX engine, in the 173cc flavor.

It even has the same size valves as a predator 212, but with a 17cc chamber!

And the crank came from a briggs 305cc I/C, walk behind blower. The impeller came to a sudden hault, and the crank let go.

I ended up repairing that engine, with the crank and charge system from a blown snowblower engine, and new rod/crank bearings seals ect. Its runs like new in my cub!
 

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mckutzy

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Ahh I see... Here I was just thnking it might have been a true Bronda crossover motor...

Wouldn't that have been quite the conglomeration of parts..... That briggs above in the pics look like that might have been it too...
 

karl

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Ahh I see... Here I was just thnking it might have been a true Bronda crossover motor...

Wouldn't that have been quite the conglomeration of parts..... That briggs above in the pics look like that might have been it too...


Sorry to disappoint, just playing with parts I had laying around, and happened to see a junk pushmower in the yard :cheers2:

This is more of just an entertainment project.

I like doing unique things , and solving dumb problems :p

I think if I did a bronda build, I would put a honda head on a flathead briggs :sifone:

I wanted this to be a zero cost project, but I lost the piston from the gx200, think it got tossed. I checked a gcv190 ohc motor, the piston fits, but the wrist pin is smaller :mad: So I will have to spend the 10 odd dollars for a replacement, the total cost for the build.

I saved a side cover from a honda eu3000 generator, that did not use an output shaft. I think the fins look cool, combined with the head. Plus I am using a predator 212 crank , extra mm of stroke.
You won't see another like it, thanks for the interest.
 

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JTSpeedDemon

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It'd probably look awesome on a minibike with that finned sidecover! Might need to make a different header though.
 

karl

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It'd probably look awesome on a minibike with that finned sidecover! Might need to make a different header though.

Yeah, the header was an off the shelf piece, I will make a custom exhaust. The head is interesting, the intake runner goes between the pushrods.

I think ill put it on a pit bike chassis, and gear it shallow to cruise comfortably at high speeds, and go 55mph+ for long distance travel. My other two bikes are more oriented for acceleration. Plus it will need a jackshaft anyway, with that fancy sidecover.

Might even splurge and pick up some 1.3 to 1 ratio rockers. I JB welded two of the oil holes, so it dont leak outside the motor, not exposed to the cylinder.

Tomorrow it will meet the belt sander, and hopefully end up with around a 11 to 1 compression ratio.
 

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karl

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I finally found the OG piston!

So I can put the bottom end together, and the exhaust is finished!
 

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karl

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I had to, well, stick the top of the piston against the disk of my 14in chop saw, tongue angle just right, to remove some off the piston, and it fits perfect, with the extra 1mm stroke of the 212 crank+rod, it's sitting in the bore about .010 in.

So now it's a true 200cc gx200, instead of 196cc, with bigger valves and boost :cheers2: The cost of the project is still at $0.

Head, sidecover, and flywheel all torqued down, barbs added, oiled up.

Next on the agenda, charge pipe. Then Booooooost.
 

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karl

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Looking good :D :D :D

Thanks, just throwing junk together :cheers2:

Finished the valvetrain, Installed a charge coil from an electric start gcv190 , to power something like an oil pump. And a gx160 shroud, gx140 recoil.
 

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karl

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That's just cool as heck, I can't wait to hear it run!

That is genuinely the coolest engine ive seen made from spare parts

Thank yall! Just having fun. Hopefully I can run it soon, the biggest challenge is the charge/ intake pipe. I am thinking of modifying this existing piece, any ideas?
 

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NewbCarter

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Dont have much to say regarding the charge pipe, im yet to figure one out for my project.. Tho, that copper return pipe looks a tad small for a return?

AN10 or larger is suggested... Tho i may borrow your cčever idea of using the hole left by the governor arm shaft as a return, rather than the hole left by the oil sensor
 

anickode

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I like the top return... Pour that oil right over the crank and rod bearing.

The line might look tiny, but that's a tiny turbo... Looks hardly bigger than my fist. ��
 
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