New to Quads

[RMFs Pappy]

Bought my 6yr old grandson 2006 90cc apex i dont think its completly stock it has a28mm carb what i need to know is can i go backwards and make this a 70cc, and by the way its air cooled for some reason I dont know if he can race a 90cc being only 6 would like some feedback please

[ndarone]

There is no way you can make that motor a 70. The 90cc cases are clearanced for a larger diameter crank. If you try to go to a 70 you will not have enough compression. You will need another motor.
If he is 6, I would look for a 50 motor that is ready to go with a carb, clutching. You can easily upgrade a 50 motor to a 70. This site is a great place to look for information on these. Keep in mind when researching that apex, drr, Eton (viper 2stroke), Polaris (2stroke) , and a handful of others use identical motors. (Yamaha designed Jog Minarelli Short )
Another great place for info is http://www.g-forcepowersports.com/ They are great about responding to any questions.

He can race a 90, but will be racing other kids on 90s. They will most likely be older 9+ some of those kids on the 90s even 50,70 can fly. If he has never been on a track, a fast kid on a 90 will be one scary endeavor.

Good Luck.

[wickestangwv]

Check out a Facebook page called Mini Quad Fanatics There is alot of experience on that page. You can put a 70 in 90 cases as well. I know shops who build national motors this way.

[bb49]

yes u can make it a 70 I do this as well as other engine builders you will need to buy a crank and a cylinder though

[RMFs Pappy]

thanks for all the input i'll keep searching this topic

[desratt]

welcome to the board. and welcome to the sport