Hi i have noticed in 3 different atv engines there is a counter balance in them or somekinda weight or something like that in the Blaster, Lt250r,and the 250x engine,, and none in the dirtbike engines! like the CR250 and Cr125 and KX65 in the engines i have taken apart.. does it hert the engine if i stick a dirtbike engine in an ATV frame? b/c it doesnt have the counter balance? or could i posibly take the counterbalance out?? get more hp's?? i have a blaster engine and a 250r engine righ now.....i care about the lt engine but not so much about the blaster LOL so please help me out and explain this 2 me! thanks

 

There are two important weights in most engines. First are the lobes near the crankpin on the crankshaft, and then there's the flywheel. Removing either would lead to a violent engine-splosion, if it even fired at all in the first place. Unless you really know what you're doing, it's best NEVER to even barely screw with the balance points of anyhing that spins that fast unless you want to die. Good luck!

 

dirtbike motors have more hp by less roolin mass in the motor, if you are using the bike motor for drag they work well. But if you want to trail ride ,mx or just play the bike motor will rattle your teeth out. Unless you devise a rubber motor mount system like the full dresser Harleys run. Good luck with it, you can have the flywheel lightened.

 

ok now my main question that i really want answered what does it do exactly what is the purpos of the counter balance?? what would happen if i removed it??
thanks

 

ok on a bike they don't need a counter balancer because of the frame and suspension, ATV need it cause of there frame and suspension. If you put a bike motor in a ATV frame it will shake, like through the handle bars and everything else.

 

so its not for more tourque??? or bottom end? thanks for the replies

 

yes it gives more torque with it because of rollin mass. But mainly for the vibration factor, I rode a cr 250 in a trx250r frame it ripped hard but the vibration weres you out so fast, you can stand to ride it.

 

ok they way i understand it and i hope i use the right terminology - is they dont put them in dirtbikes due to the basic config of a dirtbike axis (1 front tire, 1 back makes an axis); on a quad there is another front wheel and another back wheel, thus creating another axis. when the engine is vibrating in a dirtbike it isnt that noticble and gets dispersed correctly. in a quad that other axis magnifies engine vibrations that cant be disbersed now and things feel out of whack/balance and it is noticable and will shake the **** out of you if you dont have a counter-balanced engine. the cr250r doesnt have one but the trx does.

i guess i should know this- but i dont think the banshee had one - its engine was from the RZ350 street bike and i think what yamaha did was use RUBBER mounts to reduce vibration. the underside of the engine had rubber mounts. i could have had one though, seemed like it would have. but i never noticed any unreal vibration with it- some vibration- yes, untolerable- no. so if they did this without a counter balancer then the rubber mounts did their job and if you want to put a cr or other dirtbike engine in a quad frame then go to a fab shop and have them help devise a rubber mounting system. otherswise be prepared to **** all over yourself!