Hi Paul, thanks a lot for your answer.
And sorry I give news only today...
Well, unfortunatly, I didn't have the opprtunity to test a powerfull motor. My rear suspension has boke just before...
i have a lot of work to redesign one (more stronger) for August but I hope finding the time for...
Thanks again...
Anyway, I have put a Youtube video of the Ynot handling on dirt for the last french championship in the ALIEN Racing Ynot post. If you put some time to look at it, feel free to give me your comments...