First (and most important) question: why do you think it's bent? How did you measure it? How accurately did you check the tyre pressures before measuring? Did you measure tyre circumfernece? Etc. etc....
Before you decide, check the chassis against the followiung set of instructions aI wrotye for someone else, a long while ago:-
********************
Many people assume that their chassis is twisted or bent when they do the simple ‘test’. With their kart on the ground, they measure/judge how high each front wheel is off the ground when they go from full lock one way to full lock the other way. If one wheel is higher off the ground on full lock one way than the other wheel is off the ground on full lock the OTHER way, they will assume that the chassis is bent. It MAY be but other things need to be checked FIRST before making that assumption as that effect can be caused by LOTS of other problems. Here are some basic checks BEFORE making that assumption
1) The stub axles are IDENTICAL, two similar looking ones can be VERY different. I hold them back-to-back and compare while buying them. Yours may be twisted from an accident.
2) Check that you have the steering set identically on both sides i.e., that the steering rods are bolted to the same holes in the stub axles (into the bit called the ‘drag arm’).
3) Check the steering is set up with the blade of the drop link (the bit that sticks out of the steering column) is central when the wheels are pointing dead ahead. If it isn't, the amount of 'lift' will be different at full lock and you’ll THINK it’s twisted the chassis.
4) Check that circumference (and thus the diameter) of each front wheel/tyre is IDENTICAL and that both REAR wheels are also identical! You wouldn't BELIEVE the difference in tyre circumference from supposedly ‘identical’ tyres.
5) Check that the washers on both of the king pins are in the same ‘settings’. The Front Ride Height is adjusted by how many ‘washers’ you have above and/or below the stub axle (around the king pin).Obviously, if you have (for example) two washers below the stub on the right, you should also have 2 washers below the stub on the LEFT, too!
6) Check that the camber/castor adjustment (if you have them) are identical on sides, top and bottom! The top and bottom of the King Pin can be held in a ‘washer’ (often called a “Pill”) that has a hole in it that’s NOT in the ‘centre’. You can sometimes rotate the ‘Pills’ and that will adjust the Camber and/or Caster. You need to make sure that both the left and right ‘pills’ are adjusted identically. That means the top pills should match each other and the bottom pills should match each other, too. Do note that not ALL karts have this adjustment; TKM class karts are BANNED from having such adjusters!
7) Make SURE the floor of the garage where you are testing this is flat!
If it still sits wrongly, you can bet the chassis is twisted!
The second part can be nastier. If you've bent the chassis 'vertically', you may WELL have twisted it about a second axis as well. If you think of the chassis when looking from above as a cardboard box with no bottom or top you cab easily see how, by pushing one corner of the box, it would become a 'diamond' shape (Parallelogram). Your Kart can have done the same. The front and back can be still parallel, as can the sides but they are twisted into a parallelogram!
You can measure this by removing all the upper parts of the chassis (seat, engine, steering brakes, BUMPERS!) and then measuring the frame in four directions. Let's call the kart 'corners' as follows:-
Front Left King Pin hole =FL
Front Right King Pin Hole=FR
Rear Left axle mount=RL
Rear Right axle mount= RR
You now need to measure those corners as follows
FL to RL must be identical to FR to RR
FL to RR must be identical to FR to RL
If they are not identical, you need the chassis re-jigged or (sadly) you need a new one.
While the kart is partially stripped, you can check for the original twist that you mentioned. Simply place a straight steel bar from the top of one king pin to the top of the other king pin. Now stand well in front of the kart and lower your eye line until the top of axle is EXACTLY in line with that bar. If it aligns along the whole of the rear axle perfectly, it's not twisted, if it doesn't............
Finally, when it's all-straight again, CHECK THAT THE BUMPERS are not BENT as fitting the bumper (by force) will bring the twist back again!
Good luck.
Ballpark figures? Simon Wright re jigged our Wright Karts for £75. I have no idea what Tony charge. Someone else here recently suggested a company who will re-jig other chassis. Search the forums for that question and the answers.
Ian
|
|
Bent Chassis by 'barryt' (01 Mar 2011 @ 11:07)
