Setting up a new bike to go straight
Getting a new bike to go straight can be a problem. Every bike has it's own personality so to speak and it's your job to figure it out. My bikes are built with the axel all the way to the rear so if you measure from the inside of the chain adjuster to the axel block this measurement should be the exact same on both sides to start with. ( I use dial calipers to measure with ) The bike should be balanced so that it stands alone with the front wheel pointed straight ahead. If it's not, you can move the rear tire side to side a little bit. The most I have ever seen one moved is 3/8 of an inch with no ill effects. Next is the wheelie bars, Put a level on the rear rotor and shim the frame rails till the rotor is square with the ground. Next, take the level and put it on the wheelie bar axle and adjust it so it is parallel with the ground.
Now that the wheel is straight in the chassis, the bike is balanced and the wheelie bars are level it's time to head to the line. The first and most important thing is to be SURE you are lined up straight. Sometimes with a new bike it's hard to tell when the bike is lined up. It's a good idea to have sombody stand in front of you kind of direct you, at least for the first few passes. You must be sure your sitting on the bike so you don't have to much weight on one side, try lifting up your feet and see if the bike still balances, if not, adjust your seating position. Sometimes with the wide chassis there is a hump in the body for the chain to run through and it pushes you off center on the seat. I always tell the guys to do a 3 or 4- 60 footers to get the feel of the bike leaving the line then do some 330 ft runs and gradually work their way down the track.
If the bike is pulling one way or the other, now is the time to adjust the chassis to make it go straight. There are 3 different areas to adjust for. The first is off the line,
If the bike wants to go one way or the other, try moving over in the seat a little bit first. If the bike goes to the right move a little to the right to load the right side of the tire. If that does'nt work try raising the right wheelie bar 1/2 turn. DON"T cock the rear wheel for leaving the line, it will cause problems later on down the track. All adjustments for leaving the line are made with rider seating and wheelie bar adjustments.
The next area to adjust for is about mid track, the bike will still be on the bar but the rear tire is starting to round out and the speed will be in the 160 to 190 mph area. If the bike is pulling to the right at this point you would lower the left wheelie bar 1/2 turn. If you make changes here it may affect the way it leaves the line so you have to go back and try that again. If it won't leave straight, try adjusting your riding position a little bit. ( usually, if the bike leaves straight it will be ok at mid track )..
The last area to adjust for is when the wheel comes down. At this point the tire is fully rounded out and your going 180 - 200 mph. If the bike tends to pull to the right,
pull the right adjuster back .010 - .020, this will move the front of the tire to the right. This causes the rear of the bike to go to the right and leans the bike to the left which makes it turn left ( as long as the tires are rounded out ).
Cocking the rear tire only helps when both tires are on the ground and you are at speed..
There is no substitute for seat time. The WORST thing you can do is to take a new bike to a national meet and try to set it up there. It's best to go to a local track or to rent a track for a day and get it set up there then go to the national meet and kick some butt..
The biggest problem I have seen in getting a bike to go straight is Chassis Flex....This is usually caused when you try to save a few pounds by leaving out some tubes..." THE CHASSIS IS NOT THE PLACE TO SAVE WEIGHT " especially in the higher HP classes..Next we'll chat about chassis flex. it's causes and cures...