You can enter the folowing codes from the "Magic Codes" selection on the options screen. Enter the code again to disable the cheat effect. You must reenter these for each new game session. Additionally, some codes will only work in Tracks mode and have no effect in Adventure mode.

Rainbow balloons
Enter OPPOSITESATTRACT.

Green balloons
Enter TOXICOFFENDER.

Yellow balloons
Enter BODYARMOR.

Red balloons
Enter BOMBSAWAY.

Blue balloons
Enter ROCKETFUEL.

No zippers
Enter ZAPTHEZIPPERS.

Bananas slow race
Enter BOGUSBANANAS.

Unlimited bananas
Enter VITAMINB.

No bananas in multiplayer mode
Enter NOYELLOWSTUFF.

No CPU player weapons
Enter BYEBYEBALLOONS.

Two-player adventure mode
Enter JOINTVENTURE.

Alternate horn
Enter BLABBERMOUTH. Note: This code also works in Adventure mode.

Expert CPU
Enter TIMETOLOSE.

Level three items
Enter FREEFORALL.

Start race with ten bananas
Enter FREEFRUIT.

Music test
Enter JUKEBOX. A music test option will be available on the "Audio Options" menu.

Large racers
Enter ARNOLD. Note: This code also works in Adventure mode.

Small racers
Enter TEENYWEENIES. Note: This code also works in Adventure mode.

Race against same character
Enter DOUBLEVISION. Note: This code also works in Adventure mode.

View credits
Enter WHODIDTHIS. Note: Reset the Nintendo 64 to resume.

No slow down
Enter OFFROAD to drive at full speed when leaving the track.

Two Player Adventure

Enter JOINTVENTURE

Max Power on any baloon

Enter FREEFORALL

Play as T.T.:
Beat T.T.'s course times on each race under time trial mode. T.T. will be selectable after the game is reset.

Play as Drumstick:
Collect all of the trophies and amulets. Move to the central area, with the red spot that leads to all other zones. Run over the frogs near the edge of the water. Run over the frog that has a red bird perched on its head to access Drumstick.

Space World:
Collect all the trophies and amulets, then locate the sign by the lighthouse. Approach the sign and honk your horn. The lighthouse will turn into a rocket and launch into space, allowing access to the bonus fifth world.

Second adventure:
Enable the "Space World" code. Beat Wizpig on this world. An "Adventure 2" option will now be available. This adventure involves collecting platinum balloons on reversed tracks.

Quick start:
Press A at the moment the race commentator says "Get Ready" and those words fade from the screen.

Help for the Game

Diddy Kong, Pipsy,Bumper, Tiptup, Timber, Conker, Krunch, and Banjo are the 8 main drivers. Drumstick and T.T. are the other two.
  To get T.T. you have to beat his times of all the races. To get Drumstick you have to beat Wizpig the first time.
  The weapons are the missiles, boosts, shields, droppers, and magnets.
  The more powerful weapons are the heat seeking missiles, power boosts, star shield, mine, and the power magnet.
  The most powerhouse weapons are the multi-missiles, super boosts, super shield, bubble, and the mega magnet.
  At the Timber's Island place you should know where the four WORLDS are. The island being Water World (I think that's the name for it) at the island, Dino Domain being in the archway, Mountain Monster (I call it that) at the snowy area, and the Old Area or Dragon Forest at the water fall.
  At Dino Domain, you should know where the levels are. If you don't know, the key is at Ancient Lake. At the beginning you should see some brick things to the right. Search there.
  Silver Coin Chalenge is not too hard here. First few courses have some open sight coins.
The third level, Jungle Falls, has some hard ones though. The first you should leave for the second lap. The second is easy. The third is hard. You have to hit it at an angle, slide, and hope you can get on the bridge. The forth I leave for the second lap. The fifth is kind-of hard. You have to slide on it. The sixth is easy. The seventh is in that mouth. The eighth I would leave for the next lap. On the second lap get the first, fourth, and eighth. The eighth though, is kind-of-not-really hard. You have to go to the outside while entering the rib cage.
  At Hot Top Vocano, all you have to do is search. The first being behind the rock thing, the second in the tunnel, third I hope you don't miss (or else you need mental help), the fourth on the hill, fifth by the splitter thing, sixth at the other tunnel, and the seventh and eighth at the ending room.
  At Snowflake Mountain, you will come across a few hard places, not too hard.
  The silver coin thingy isn't too hard either. Only, at Walrus Cove, you may come across a few hard ones. They are possible.
  At Frosty Village, you will see three arches. Go to the left one. You will find a silver coin. The second is at the house area. The third and fourth aren't too hard. The fifth is at the right hand side of the mini lake. The sixth is like the fifth only in the water. The seventh is past the starting line by the left hand side edge. The eighth is in the right of the three arches.
  Water World( I think it's  called Yogurt Island or something like that) is close to the lighthouse. In there you should find some real easy places. A lot of easy silver coin thingies too. The hard one is at Crescent Island, you will find some hard ones.
  At the Dragon Forest place you will find some real hard courses. I mean REAL HARD. First at Windmill Plains all the coins are easy. At Greenwood Village, you need some major help. The first is at the left edge by the well. The second is at the right side on the other side of the well. The third is hard, it is at the left side of the sharp turn area in the tunnel. The fourth is kind-of easy. So is the fifth. (Call 911, you will have a lot of trouble with #6) The sixth is by the boost thing, don't hit the boost, you will see a sharp turn to the left. In the tunnel there is the sixth. After you get it don't turn right, do a power slide to the left. After about 100 tries of that you will find some hard turns, the seventh coin is amoungst them. The eighth is close to where you found the sixth, only don't take a left, go straight. The other place is easy. Along with Haunted Woods.
  Wizpig does not let you have weapons, but he gives you boosts.
  The Pig Planet is also easy. You may have some hard turns, but you can beat it in maybe 1,2,3, or 4 days.
  I have not yet beaten the Wizpig rematch.


       Fifth Secret World

Get all amulets and trophies. Go to the lighthouse and you'll see a board with trophies on it go through the board and it will turn into a space ship and take you to the space world. There will be four new tracks and Wiz Pig will be there.
ALSO REPORTED as just beat Wiz Pig to do this!!

Bridge Hint

In Boulder Canyon(in Dragon Forest), you can raise the bridge and cause the racers behind you fall into the water(they will then take the longer route).
 
First, you must hit the blue balloon on the left side of the road(after you cross the bridge).  Then, you go straight and hit the bell hanging from a chain.
Info submitted by Eddie on Tuesday, August 31, 1999 at 18:07:54

Times to beat to play as T.T

ACIENT LAKE 1:07.00
FOSSIL CANYON 1:37.00
JUNGLE FALLS 1:08.00
HOT TOP VOLCANO 1:35.00
EVERFROST PEAK 1:53.00
WALRUS COVE 2:10.00
SNOWBALL VALLEY 1:13.00
FROSTY VILLAGE 1:44.00
WHALE BAY 1:19.00
CRESCENT ISLAND 1:39.00
PIRATE LAGOON 1:34.00
TREASURE CAVE 1:10.00
WINDMILL PLAINS 2:2200
GREENWOOD VILLAGE 1:46.00
BOULDER CANYON 2:11.00
HAUNTED WOODS 1:22.00
SPACE DUST ALLEY 2:12.00
DARKMOON CAVERNS 2:20.00
SPACEPORT ALPHA 2:16.00
STAR CITY 2:07.00