In a large bowl, place the chicken with the lemon juice. Cover and refrigerate for 2 hours.
Prepare a marinade, mixing in a large bowl the onion, garlic, beer and soy sauce.
Add the lemon juice from the chicken to the marinade. Place the chicken in the marinade, cover and refrigerate overnight.
Take the chicken from the marinade and grill until done.Turn the chicken pieces every 10 minutes and every time re dipped in the marinade.