212cc Budget mods!

jewwlion

jewwlion

New Member
#1
#1
Hey there guys I recently finished building a minibike running a 212cc Predator. For now its completely stock and I measured speed straight out of box and it runs at about 25 mph (limiter screw removed). I was wondering if I could get the engine up to ~35 for less than about $100-$200. I'm also wondering how much faster an OldMiniBikes jet kit and air filter would make the engine too. Thanks!

EDIT: I don't want to take off the governor.
 
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OND

OND

#2
#2
If you don't want to take off the govenor,,...why not just change your rear gear, If its a 70 tooth put on a 60 tooth for more mph.
 
J

jbrocks

New Member
#3
#3
Hey jewwlion, welcome to OldMiniBikes! Off the top, you should get 35mph with a stock 212. If you're not, your gearing may be off. How many tooth clutch? Rear sprocket? Average is 12t clutch/72t rear sprocket (I actually use a 11t clutch/60t rear and hit low 40s.) A lot of guys are doing a light engine mod of intakes/airfilter/header to squeak some more power out of it. It's totally worth doing. You can buy that upgrade kit from OldMiniBikes for about $88.Predator 212cc Mini Bike Kit - Stage 1 - Hemi

Good luck and post some pics:thumbsup:
 
jewwlion

jewwlion

New Member
#4
#4
Hey there. I currently have a standard 12 tooth clutch, 72 tooth sprocket. How could I fix the gearing issue? I forgot to mention earlier that the engine is actually not totally stock. It has upgraded valve springs.
 
Moedog07

Moedog07

New Member
#6
#6
Buy the drill bits off Ebay and you can open up the stock jets. You can reuse the bits over and over. Buy or build a header. K&N style air filter and you are going to see a difference. Swapping the rear sprocket is a must if you don't want to remove the governor to turn more RPM's.
 
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minibikin'

minibikin'

Sho-nuff
#12
#12
The non hemi kit comes with valve springs. Not necessarily needed until you remove the governor but you would have them if you decide to do so.


Sent from my Texas Instruments Speak and Spell...[emoji2]
 
cxbra

cxbra

New Member
#13
#13
Those engine modifications will do nothing for your top speed.. What they will do is pull the bike out from under you and lay you down on the pavement :). You need to change your gear ratio if you want higher top speed. Im running a 12/72 ratio also and I absolutely love it, I want to go to 13/72 or 14/72 but im afraid of losing my wheelies haha. I would kind of like my gearing/powerband set up to wheelie from 15mph-35mph because right now it wheelies from about 5mph up to 25mph and the front wheel comes up too soon, sometimes when I dont expect it! The solution is simple for you though, if you need more top speed then gearing is your only option on a governed/stock-head engine. If you want more acceleration, you can do it through gearing OR power. You should re-gear the bike with a 60 tooth, then add the engine modifications and it might have the same acceleration that it did before, AND 10mph higher top speed.
 
thewildherbie

thewildherbie

New Member
#14
#14
cxbra said:
Those engine modifications will do nothing for your top speed.. What they will do is pull the bike out from under you and lay you down on the pavement :). You need to change your gear ratio if you want higher top speed. Im running a 12/72 ratio also and I absolutely love it, I want to go to 13/72 or 14/72 but im afraid of losing my wheelies haha. I would kind of like my gearing/powerband set up to wheelie from 15mph-35mph because right now it wheelies from about 5mph up to 25mph and the front wheel comes up too soon, sometimes when I dont expect it! The solution is simple for you though, if you need more top speed then gearing is your only option on a governed/stock-head engine. If you want more acceleration, you can do it through gearing OR power. You should re-gear the bike with a 60 tooth, then add the engine modifications and it might have the same acceleration that it did before, AND 10mph higher top speed.
Click to expand...
THIS. If you wanna go fast you're gonna have to change your sprocket and/or clutch. I would recommend using a torque converter rather than a clutch.
 
R

Rippin

New Member
#15
#15
jbrocks said:
Hey jewwlion, welcome to OldMiniBikes! Off the top, you should get 35mph with a stock 212. If you're not, your gearing may be off. How many tooth clutch? Rear sprocket? Average is 12t clutch/72t rear sprocket (I actually use a 11t clutch/60t rear and hit low 40s.) A lot of guys are doing a light engine mod of intakes/airfilter/header to squeak some more power out of it. It's totally worth doing. You can buy that upgrade kit from OldMiniBikes for about $88. Predator 212cc Mini Bike Kit - Stage 1 -

Good luck and post some pics:thumbsup:
Click to expand...
Would this work for the 79.5 cc ohv Monster Moto MM-B80r? sorry im new to to these bikes and want to upgrade my shit
 
cxbra

cxbra

New Member
#16
#16
Horsepower means absolute nothing, its all about gearing x rpms! You could have a 20hp engine, but if its geared wrong then it will only go 25mph (and the front wheel will never be on the ground either). A bone stock out of the box Predator 212cc will do 45mph no problem if you gear it for that speed. I used to run 12/60 on my old Bonanza with a modded 5hp flathead (45mph) but now im running 12/72 on my El Tigre with Predator 212cc (35mph).
 
Milton Friedman

Milton Friedman

New Member
#17
#17
cxbra said:
Horsepower means absolute nothing, its all about gearing x rpms! You could have a 20hp engine, but if its geared wrong then it will only go 25mph (and the front wheel will never be on the ground either). A bone stock out of the box Predator 212cc will do 45mph no problem if you gear it for that speed. I used to run 12/60 on my old Bonanza with a modded 5hp flathead (45mph) but now im running 12/72 on my El Tigre with Predator 212cc (35mph).
Click to expand...
Of course HP matters - if there's too much load on the engine it will lose power far before it even spins up enough to get to your desired speed.
 
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