Birel karts.....Easykarts.....Monza Karts.....Rotax Motors.....Honda Shifters.....TM Motors.....Yamaha.....MG Tires.....Bridgestone.....Motul.....Redline.....Burris.....Mychron.....Sniper.....Sparco.....Alpine Stars.....Streeter Stands.....Kartlift.....Keihen.....Dellorto.....RLV.....RCE.....

A    Crotch to Gas tank :             3 in                                1 in
B    Back of seat to Axle : All at 8.25in to 9.00 in
C    Engine side to front chassis rail : 0.5 in longer (with factory seat- 23")
D    Brake side to front chassis rail : 0.5 in shorter (with factory seat- 22.5")
E    Bottom of seat to chassis rail: level to bottom of rail to 0.5 inch below
Note: you can bend chassis ‘tabs’ at bottom of seat to fit seat contour….

Weight Distribution :
Start with 45% front / 55% rear with driver and fuel onboard.
Moving weight and/or the seat is very critical in all kart setup.
More weight forward - gives more front grip.
More weight backward - gives more rear grip.

Tire Pressures :
Starting at 9 - 11 lbs. cold for most soft compound tires or 12 - 14 lbs. cold for most harder compound tires
Correct pressure should result in a pressure increase of no more than 2 lbs when hot.
Use Magnesium rims to control air pressure variances.
Nitrogen gas is recommended to reduce air pressure variances.

Toe-in settings : 0 deg - on kart stand (begin set-up)

Camber :
can use offset bushing depending on front tire wear - 0.5 deg and 1.5 deg available
more camber - more grip at front
less camber - less grip at front

Tie Rods Mounting :
Mount to outer holes of spindle for slower steering response
Mount to inner holes of spindle for faster steering response 

Steering :
upper mounting - max Ackerman - softer steering - more responsive
lower mounting - less Ackerman - harder steering - less responsive

Torsion Bar : For Birel Torsion karts only:
#1 bar - softest bar - least grip to rear
#2 bar - stiffer than #1 - gives more grip to rear
Standard bar - has no number stamped on it - medium stiffness
#3 bar - stiffer yet still - increases rear grip
#4 bar - stiffest bar - gives most rear grip
Note: varying the number of clamps used with the bar will also control stiffness

Spindle Height :
Raise spindle = lower frame - less grip at front
Lower spindle = raise frame - more grip at front  

Front Track :
out - more grip .....
in - less grip
****see footnote on push**** 

Length of Hubs :
longer hubs gives more grip
shorter hubs gives les grip 

Axle Hardness :
stiffer axle gives more rear grip
softer axle gives less rear grip
F - soft
M - standard
K - stiffest

Rear Bumper :
loosen bolt - more flexing - less rear grip
tighten bolt - less flexing - more rear grip

Rear Push Bar :
can use it to stiffen up chassis also, provides more rear grip if tightened

Seat Struts :
More struts for more grip in rear

Shifter Kart beginning setup:

F axle (50mm karts) M axle (40mm karts)
Medium or Long Hubs in rear
Standard (middle position) spindle height
0 deg toe in
Use outer spindle hole for tie rods attachment
front track width at 1 1/2in from brake disc
rear track width at 54.75in

WET Setup : 
No seat struts
front as wide as possible - ( Shifter : use 125mm Hubs at front )
rear in as much as you can
move seat forward and up
increase camber
increase caster
lower front spindle ( raise frame )
mount tie rod to lower mounting position on steering column
remove rear blade bar
loosen up rear bumper and push bar
increase tire pressure
Torsion chassis- remove clamps on the Torsion bar - use plastic tie

Summary

At a new track, you need to start with a ‘neutral’ setup and then make your adjustments based on what the kart is doing and how the track is changing. Usually it is best that you choose as your start set-up the one that you use at your home track. Then you have a comparison with what you are always used to. If the kart ‘pushes’ or understeers, then you need to add grip to the front by any or all the ways described above. If the kart is ‘loose’ or oversteers, then you need to increase rear grip using these methods.

Please note, if you have a kart that is ‘pushing’ badly and you have already done all things to put more grip up front, then you need to take grip away from the rear. This would usually mean that an axle change to a softer axle is necessary. Always think of the kart as a whole and that you need to have a balance.

Also to consider, you may get a push going into the corner ( it shows on the front tire as wear on the inside only ), then you can try moving the front tires in. Then you may have a condition where the kart pushes in the middle or coming out of the corner ( it shows on the front tire as wear on the middle and outside ), then try moving the front tires out.

The notes above would be for your basic knowledge of the BIREL chassis. Time permitting, I strongly recommend making only one change at a time. I recommend that you use a couple test sessions to familiarize yourself with your new BIREL, so on raceday you can confidently make changes to your kart. It is important that you know which changes result in large gains and which you would need for small gains.

Good luck and have a safe day racing.

Rudy.

Last updated 2/15/08

___________________________________________________________________________________________________________
3970 NW 132 Street  Bay A   Miami  FL  33054             Phone: (305) 687-8711          Fax: (305) 687-8712               rysaracing@aol.com
Daily Shipments using FED Ex or UPS               Copyright 2010 - 2015 RYSA Racing, Inc             RYSA Racing accepts all Major Credit Cards