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Link Posted: 2/21/2024 3:23:28 PM EDT
[#1]
Quoted:
I bought this here mini bike around a year ago. Put a gokart 212cc motor in it. I had a lot of fun with it this last year but always kinda wanted a little more out of the engine. Threw a cam, billet rod, billet flywheel, and some valve springs at it. Noticeable gains

Currently does 50 which is scooting pretty good

But Im not sure I can leave good enough alone

Harbor freight has the 420cc engine which from research will fit my frame. Albeit Ill have to do some modifying and pull out the CVT and replace with a bigger heavier. Itll be a good little bit of work with fitting and welding. Im sure eventually Id want to throw the go fast parts at this engine as well.

The weight difference is quite a bit though. The 212cc is ~36 pounds. the 420cc coming in at a bit under 80 pounds. Id be surprised if the frame and tires weigh 80 pounds

Is the juice gunna be worth the squeeze? Double the CCs double the fun? Double the weight and no fun?

ETA Now looking at amazon ATV/Dirt bike motors

https://www.ar15.com/media/mediaFiles/161977/20230414_171005-2785286.jpg

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Sel it and buy a dirt bike or street bike built to do what you want.
VP
Link Posted: 2/21/2024 3:24:55 PM EDT
[#2]
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Quoted:




Sel it and buy a dirt bike or street bike built to do what you want.
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Quoted:
Quoted:
I bought this here mini bike around a year ago. Put a gokart 212cc motor in it. I had a lot of fun with it this last year but always kinda wanted a little more out of the engine. Threw a cam, billet rod, billet flywheel, and some valve springs at it. Noticeable gains

Currently does 50 which is scooting pretty good

But Im not sure I can leave good enough alone

Harbor freight has the 420cc engine which from research will fit my frame. Albeit Ill have to do some modifying and pull out the CVT and replace with a bigger heavier. Itll be a good little bit of work with fitting and welding. Im sure eventually Id want to throw the go fast parts at this engine as well.

The weight difference is quite a bit though. The 212cc is ~36 pounds. the 420cc coming in at a bit under 80 pounds. Id be surprised if the frame and tires weigh 80 pounds

Is the juice gunna be worth the squeeze? Double the CCs double the fun? Double the weight and no fun?

ETA Now looking at amazon ATV/Dirt bike motors

https://www.ar15.com/media/mediaFiles/161977/20230414_171005-2785286.jpg





Sel it and buy a dirt bike or street bike built to do what you want.


Where's the fun in that?
Link Posted: 2/21/2024 3:53:57 PM EDT
[#3]
The handling characteristics on that thing would have me not wanting to go any faster than you already are. Build yourself a shifter kart if you really want to have fun with small engines.
Link Posted: 2/21/2024 4:04:17 PM EDT
[#4]
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Quoted:
The handling characteristics on that thing would have me not wanting to go any faster than you already are. Build yourself a shifter kart if you really want to have fun with small engines.
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Maybe I havent ridden a lot of stuff but its handled great so far. Its not sketchy at all at 50

I dont have anyway to transport a shifter cart
Link Posted: 2/21/2024 5:30:34 PM EDT
[#5]
I do wonder if Im going to run into issues adapting the chain

It looks like the engine chain is going to be a 248H

My driveline right now uses a 420

That said the driveline is on the right side

The engine drive is on the left

Maybe I could find a sprocket for the engine side jackshaft and then keep the 420 chain on the right like it is currently

But so far Im not finding any 428 sprockets that will fit the jackshaft I got. Then again it looks like Im running across 420 sprockets that might fit the engine
Link Posted: 2/21/2024 7:32:40 PM EDT
[#6]
Well I rode it when I got home real quick

Maybe its because i havent rode it since fall. I got to admit that 212 straight kicks some ass riding around the neighborhood

For its size it delivers some amazing power after the parts were thrown at it
Link Posted: 2/21/2024 7:40:15 PM EDT
[#7]
Dew this!!!! I want to do the same.

Got my 14 YO son a Coleman for Christmas. After Christmas I realized it was a blast, and went and got ME a used Axis off marketplace.

We have woods and river bottoms. These damn things will literally go anywhere. They are more fun than they ought to be. His new one was $699 and my used one was $325.

Sure, I know real ATV's would be better, but kind of like OP, my wife doesn't mind the minibikes- doesn't count them as dangerous as 'the real thing' somehow. Also like OP, I like to tinker on things. You can do a lot of tinkering for not much cash on these platforms. And they ride pretty good. Not at all like the classic vintage minibikes most remember.  

I want a little more umph out of mine. So far I've got a pipe with tip muffler, open air filter and a re-jetted carb. Removed the throttle stop, but I haven't touched the governor yet.  Would like to do the billet flywheel and rod so I can safely get more RPM, but I don't want to lose the headlight as there is no billet flywheel with lighting coils.  

We tool around in the evenings after supper. The headlight is kind of critical.  I have put an upgraded LED bulb in the stock housing, and now it's pretty bright.

Been planning to do the torque converter mod, but a motorcycle style engine with actual tranny would be amazing.

Do those motorcycle style engines have lighting/charging coils integrated?
Link Posted: 2/21/2024 7:42:05 PM EDT
[#8]
So are you that guy that whips out of the trailer park in pitch darkness at 2am and flies across four lanes of traffic into the Taco Bell parking lot while people in cars slam their brakes and horns? I think I've seen you!
Link Posted: 2/21/2024 7:50:04 PM EDT
[#9]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


No shit?

Where's a guy look at aftermarket parts for this kinda engine?

What chain does the sprocket that comes with it take? I can't seem to find that info off hand
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I have one of those 229cc (they're not 250cc) CG motors in a chinese dirt bike that's making about 20bhp and revs to 9500rpm. Basically the exhaust ports and systems are garbage, but you can easily improve them and the motors respond really well to this. Then I skimmed the head raising the CR to 9.5:1 , added 4 degrees of advance to timing and put in a 290degree cam. The stock VM26 carb was good enough, but now it runs massive jets and a pod style filter


No shit?

Where's a guy look at aftermarket parts for this kinda engine?

What chain does the sprocket that comes with it take? I can't seem to find that info off hand

the arfcom of chinese CG engine performance
Link Posted: 2/21/2024 7:50:57 PM EDT
[#10]
Nope, I'm pretty rural.  I got trails and dirt roads. No need to be on a street.
Link Posted: 2/21/2024 8:39:34 PM EDT
[#11]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Dew this!!!! I want to do the same.

Got my 14 YO son a Coleman for Christmas. After Christmas I realized it was a blast, and went and got ME a used Axis off marketplace.

We have woods and river bottoms. These damn things will literally go anywhere. They are more fun than they ought to be. His new one was $699 and my used one was $325.

Sure, I know real ATV's would be better, but kind of like OP, my wife doesn't mind the minibikes- doesn't count them as dangerous as 'the real thing' somehow. Also like OP, I like to tinker on things. You can do a lot of tinkering for not much cash on these platforms. And they ride pretty good. Not at all like the classic vintage minibikes most remember.  

I want a little more umph out of mine. So far I've got a pipe with tip muffler, open air filter and a re-jetted carb. Removed the throttle stop, but I haven't touched the governor yet.  Would like to do the billet flywheel and rod so I can safely get more RPM, but I don't want to lose the headlight as there is no billet flywheel with lighting coils.  

We tool around in the evenings after supper. The headlight is kind of critical.  I have put an upgraded LED bulb in the stock housing, and now it's pretty bright.

Been planning to do the torque converter mod, but a motorcycle style engine with actual tranny would be amazing.

Do those motorcycle style engines have lighting/charging coils integrated?
View Quote



Yeah I threw the parts book at this 212. Cam, rod, no gov, advanced timing, coil pack, valve springs and flywheel. It's honestly pretty strong for its size. Riding it today it still surprised me.

I'm not sure on the dirt bike motor so far. One would think that it does like on a real bike or atv. I'm gunna have to look into them a bit more
Link Posted: 2/21/2024 10:09:26 PM EDT
[#12]
OK
What you have is a underpowered toy with marginal handling , suspension and brakes .

By doing engine work you get more power and speed but because of that stuff the handling , suspension and brakes have become more marginal .

Upping the power (sounds like by a good percentage) and weight is going to make the substandard features pretty scarry.

Take the money you were going to spend and put it towards a dirt bike or enduro . It will cost you more in the end but you will get way more capability and generally better safe use of the thing . You will also have something with considerable resale value.

Stuff a pile of money into your present bike and it will likely be something only you can ride and something most others will not want ,
Link Posted: 2/21/2024 11:20:05 PM EDT
[#13]
Either you 'get it', or you don't. Lots of people enjoy these minibikes for what they are- cheap, easily manageable vehicles with some off-road capability. I won't argue with any of your points.  I don't care about them either.  We don't own real ATV's. Too expensive for the amount they would get used.  I wouldn't expect anyone who does own/ride real ATV's to see these minibikes as anything but a joke. But, the sales of them have really exploded and they are putting a dent in the real ATV market as people realize the minibikes are actually pretty capable for basic off road transportation and recreation.

I'm having fun, teaching my kid how engines and power trains work, and NOT spending much money at all. If I put a rod thru the block tomorrow I can just go down to harbor freight and get a brand new engine for $120 and be riding again in an hour.

But, based on how long the predator on the kids old gokart has lasted, I don't really anticipate much problems.  I have not modified mine very heavily.  But, at the same time, the old hot-rodder inside me is naturally inclined to improve it as much as possible, within reason.

It's just something inexpensive to have fun with.  

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