Hawg wild on a china girl motorized bicycle

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RicksRides

RicksRides

Member
Feb 22, 2012
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osceola IN
Here,s the deal the son in law brought over a china girl today, asking if I could go hawg wild on it, he'd pay for it. One of the first things I did when building dragbikes years ago was to turn or lighten and weld the crank, makes it rev faster and higher. (Anyone do this to a china girl if so, how did it turn out.) Install the equivalent of a big bore kit. Wiesco will more then likely have a piston and cylinder sleeve I can use Ill have to epoxy the jug or mill a new one and I'm sure it'll require some crank case clean up Advance the timing either when I re assemble the crank or with an off set key. Deck the head and modify to install a second plug, port and polish everything. Tunable expansion chamber,walbro methane-alcohol carb and fuel pump ,copper gasket and high performance bearrings, HD studs as well as other misc upgrades. You guys out there who deal with these motors on a regular basis let me what the furthest you,ve beefed these motors up and if it'll hold together. This will be my first china girl. thanks Rick
 
Ibedayank

Ibedayank

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Oct 29, 2011
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Re: Hawg wild on a china girl

sleeving a $20 cylinder that is ported when there is not enough metal in the cylinder to bore it out in the first place may be impossible. these cylinders are ported there are no reed valves
 
Bikeguy Joe

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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Re: Hawg wild on a china girl

Not sure which one you have, but they can't be bored....they have a nikasil type plating as a liner.
 
RicksRides

RicksRides

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Feb 22, 2012
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osceola IN
Re: Hawg wild on a china girl

Okay better question yet what would be hawg wild on one of these lil motors. My experience comes from building big kaws in late 80's and 90s and 2 stroke karts in the early 80's
 
rustycase

rustycase

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May 26, 2011
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Re: Hawg wild on a china girl

Sounds like a lot of fun!

Might be able to put a polini top end on one... for an old puch, or something like that.

These little HTs are just not a quality piece of equipment, though, worthy of big $ investments, at least IMO... :)

Honestly, you would be far better off beginning with a morini, or the ktm clone DAX is selling, or the 4cycle 99cc motors from HF.

Oh, in 2 strokes the hotrod guys do a thing called crankcase stuffing, to get superior compression in there, and better flow up through the transfer ports.
Turning down a crank to lighten it would probably NOT be a good thing!

Good luck!
I can tell you're gonna build a nice one!
rc
 
Mannhouse51

Mannhouse51

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Jun 2, 2011
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Re: Hawg wild on a china girl

I'm sitten here laughing. All that work into a HT engine thats made out of what may be the worst quality aluminum on the planet and not much of it to boot. The cases may be a bit too thin as are the cylinders. With that being said , Go For It ! Can't wait to hear how it goes.
 
rustycase

rustycase

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May 26, 2011
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Re: Hawg wild on a china girl

M51 is right... if you take just a single minute, and look at the motor mounting studs, or the exhaust studs, you will see what is a good example of the probs with a chinagirl...
They are ...right on the edge... of the casting.
There ain't hardly anything there to work with.

lol
I just made a front motor mount bracket... then I had to make it crooked, so it would line up right! lol

It can be done, though.

I think them motovelo guys down in the big city pumped 'em up quite a bit.
Not a clue how long the motors lived, though.

I can't wait to see what ur gonna build! :)
rc
 
RicksRides

RicksRides

Member
Feb 22, 2012
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osceola IN
Re: Hawg wild on a china girl

I dont know much bout these motors thought id ask b4 tearing into it or wasting my time or effort. I dont mind if the dog chases his tail, but, I dont wanna be chasing mine so to speak. For my own builds, Ill be using some of the gravely model L's I bought American made Cast Iron!! I also have some for sale
 
dragray

dragray

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Mar 10, 2012
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Re: Hawg wild on a china girl

i'd say after he starts it he'll hear "knock, knock?"
to which he'll reply "who's there?"
then he'll hear "Ka!"
he'll then reply "Ka who?"
then he'll hear "KA-BOOOM!"
these things are throw away engines made with the cheapest aluminum possible.
I wouldn't trust the crank at all, especially if you lighten it. the bearings would need to be replaced with some very high quality ones, the piston pin would probably break from the extra compression.
these are ported engines (no reed valves like a quality japan 2 stroke on a dirt bike or go kart i.e. yamaha)
you'll be breaking spokes with much more power than these things make stock, but i don't think it would even run long enough for you to take a test ride on it. unless you install a motorcycle rear wheel.
I think you'd be wasting your time and money. if you want to go this route, why not just install a yamaha yz 80 engine on the bike with the transmission?

just buuild it stock and add some of the bolt on parts (like an expansion chamber, high flow filter, better plug, better plug wire, etc.) and go for the look of a drag bike....that's what i did. it's all about the illusion my friend. sure, it only tops out at 28 mph, but sitting still, a lot of people are afraid of it because it looks like it'll go a lot faster.
 
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RicksRides

RicksRides

Member
Feb 22, 2012
864
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osceola IN
Re: Hawg wild on a china girl

Son in law asked me to go hawg wild on it not my money . My question however is what is considered hawg wild with these motorsI offered him a 98cc 2stroke shifter kart engine he showed up with a china girl ?????
 
NunyaBidness

NunyaBidness

Active Member
Jun 29, 2008
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memphis tn
Re: Hawg wild on a china girl

Look at some of Bairdcos builds. You can do some clean up work inside, install better bearings, better hardware all the way around, expansion chamber and better carb. There is some cool stuff you can do to these engines, how long they last is a different story.

I'm interested in what you do to it. Start a build thread when you do it, what ever it is you do to it.
.wee.
 
RicksRides

RicksRides

Member
Feb 22, 2012
864
6
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osceola IN
Re: Hawg wild on a china girl

I told him at last count i had over 70 engines various types most of them can be crammed in a bike the others need custom frames. They are all better choices than a china girl
 
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