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help with predator 212cc motor

8K views 25 replies 6 participants last post by  MrKitty 
#1 ·
hey all, i wanted to change out my 50cc uberscoot stock motor for predator 212cc, can i leave the 2 speed gearbox on or does it need new tranamission, i wanted to go hopefully 40mph with scooter and 212cc, i weigh 264...any info is appreciated
 

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#5 ·
Do you have a death wish?? The 212cc is way to heavy for your scooter and the low end torque will flip over on you, or you to lose control. In Calif. the top speed is 30 MPH to stay legal.
 
#9 ·
The problem is four strokes have torque and not rpm so you need a way to convert that torque into RPM with some kind of CVT or transmission gerd at the right ratio for the engine

You would probably be much better off modifying the engine you already have.
 
#10 · (Edited)
This is the 2 speed setup he needs but for an engine as big as the 6.5 or 7hp Predator he only needs to modify the engine to run without the governor and a Torque-a-verter and he will do 50-55 mph without a 2 speed transmission.........…............



One thing about putting such a heavy torque monster of an engine on a scooter frame...It wont be easy to control due to the weight of the engine is gonna be the culprit....

I tried putting a 5hp flattop on a GSMoon scooter....I turned it into a mini-minibike....LOL



If the OP would learn how to port and modify the engine he has he will be able to hit 40mph with what he has.........…


When this pic was taken my homemade stand-up scooter did 42-43mph with a modded 49cc engine and a CVT transmission.....


 

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#12 · (Edited)
you can do a base gasket delet mod to up the compershon port and blueprint the cylinder and crankcase lighten the flywheel turbo crank mod lighten the wrist pin add a rocket key and a boost bottle and that thing will crank out the sweet sound of stellar RPMs for basicly free...

if you want to spend some money you can put SKF bearings in the crankcase and try to find some Japanese crankcase seals for a genuine Honda brush cutter.

bolt on performance parts are not the way to go...
 
#15 ·
Only of you dont totally disassemble the engine to build it up........

You dont want gasket pieces getting in the crankcase or the crank bearings......

Its a lil more than just removing a gasket but it isnt overly hard if you follow and adhere to the laymans directions to modifying these types of engines or you will need to learn how to use a degree wheel...........

Just know that these engines were never intended for rideables and the extra loads exerted on them...Theyre backpack blower, auger , trashpump and brushcutter replacement engines adapted to be put on rideables....

The engine you have is a knockoff of real Mitsubishi brand 2 stroke engine...

If you do a proper search and read through the threads youll find plenty of information.....

Good luck
 
#14 · (Edited)
its supper easy all you do is pull the cylinder off use some brake cleaner and a plastic razor blade (not the typical metal ones) and gently remove the old gasket remnants not leting any fall into the crank case then apply a micro thin layer of yamabond or hondabond to the jug and slide the cylinder back on well compersing the rings with your fingers to help them start tighten her up and enjoy free horsepower...

if you add a rocket key and boost bottle at the same time you will notace a big difference in performance...
 

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#21 · (Edited)
It means to take your fingers and make the flexible sealing rings the same size as the piston in order to marry the piston and the cylinder together....If the rings didn't flex with as much pressure as they do the engine would have a hard time making compression..


Think he is talking about compressing the rings on the piston to put the cyld on. If you have 2 wood ice cream sticks modified and someone hold the cyld you can press the rings in and slide the cyld over the piston.
I simply pinch both rings with my fingers on the sides of the piston where the transfer ports are then carefully guide the cylinder over the piston and marry them both together..

For the guys and gals with hands too small to achieve that they can purchase a STENS brand ring compressor assortment pack for $12.

https://www.amazon.com/Stens-751-04...hvlocphy=&hvtargid=pla-4584001418535170&psc=1
 
#20 · (Edited)
Yamabond will not work on an exhaust manifold gasket neither will rubber fiber gasket material in the long run as the exhaust pipe will just cut right through it when the pipe bolts are tightened.....A real good exhaust gasket is layered with aluminum or made of thick layered graphite and beaded steel.....

https://www.ebay.com/itm/Exhaust-Ga...a=1&pg=2047675&_trksid=p2047675.c100010.m2109

Do you have a lawnmower repair shop nearby? Tell them you want an exhaust gasket for an Echo backpack blower model PB503T...Just be prepared to pay 3x as much as the ebay link I provided.....

If you do and go there dont say pocketbike as most mowershops hate them and may refuse to sell parts to you.....

Good Luck
 
#18 ·
you can get gasket material at the auto parts store and cut one out yourself RTV orang is high temp silicone design for exhaust use you can also get that at the auto parts store but I don't recommend it because it tends to ooz and block some of the exhaust port but if your carfull you can just RTV it

We like to use yamabond or hondabond because it is resistant to two-stroke oil and fuel if you use RTV it will slowly erode away when used on a cylinder 2 crank case application
 
#19 ·
Think he is talking about compressing the rings on the piston to put the cyld on. If you have 2 wood ice cream sticks modified and someone hold the cyld you can press the rings in and slide the cyld over the piston.
 
#22 ·
I've found with my drift trikes, that the predator or Honda GX200 motors delivers huge torque and a very flat power curve of near peak power through the rev range.

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The polini or China C1 only pull when the revs really get up into powerband.

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So it depends on application, but if you wanted power at any range the GX200 will deliver. If you want to bog down low but have high end top speed the polini is probably the right way to go.

The other advantage of the polini is size and weight. They are little motors and look like the belong on a goped.

I'm about to make another goped bigfoot converted to either cag or polini. I've done a cag with great success and want to do it again...but more top end would be fun:)

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And the next project will be based on this one.

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Guess what I'm saying is torque is more important for acceleration than power. But power get top speed.

Torque = the ability to do work
Power = how much work you can do
 
#23 · (Edited)
I've found with my drift trikes, that the predator or Honda GX200 motors delivers huge torque and a very flat power curve of near peak power through the rev range.

View attachment 149291

The polini or China C1 only pull when the revs really get up into powerband.

View attachment 149289

So it depends on application, but if you wanted power at any range the GX200 will deliver. If you want to bog down low but have high end top speed the polini is probably the right way to go.

The other advantage of the polini is size and weight. They are little motors and look like the belong on a goped.

I'm about to make another goped bigfoot converted to either cag or polini. I've done a cag with great success and want to do it again...but more top end would be fun:)

View attachment 149293

And the next project will be based on this one.

View attachment 149287

Guess what I'm saying is torque is more important for acceleration than power. But power get top speed.

Torque = the ability to do work
Power = how much work you can do
Yeah I agree although you're basically comparing a 39cc engine to 212ccs.....The piston sizes are world's apart.

In every motorbike application you want torque...Some can deliver where as some can't....One day they'll have one that can deliver all-around power but it will have to be an EFI 4stroke with VVT solenoids with no timing chain at all...Kinda like my CBR600 build-up ...lol....That thing could pull a freight train and also rev to 20k with a crossplane crankshat.... lol....
 
#24 ·
race bike / track bike engines like polini balta bizetas all love to make power up high on the track 8 to 13K where the clutch stays locked burning nice high octain VP105

then people take them on the street stop and go burning up the clutch running pump gas putting holes in the top of the piston and sooner then later it overheats and melts down and it just galls the living crap out of the cylinder and blows the connecting rod bearings. and they cant figure out why.
 
#25 · (Edited)
Why should it matter what people do with their junk??...Its not like theres organized racing in every state anymore and also to mention theirs to do with what they please..........

Theres dudes over in quatar who blow-up 8-10 $35,000.00 engines each car in just 1 night all in the first 20-25 seconds trying to climb vertical sand hills that are impossible to climb....

Why?;- do you ask?....Answer is because they can.....LOL

This summer I was given the chance to drive a 2020 mid enginned Corvette for a few weeks to put through its paces then it went through a huge data unload then off to a customizer whos in the middle of totally tearing down the whole car to make it even wickeder than it already is....LOL...

Do you think I took it easy?....lol...I got it with 5 miles on it and laid down a burner about 300ft on the very first takeoff.........LOL.
 
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