Nerf bar bolts – Just because the bolt was put back in doesn’t mean the bolt was ever tightened. If I had a dollar for ever pod I ever seen fly off a kart during a race.
Rear bumpers – Way too many plastic rear bumpers come off on one side of the kart and in most series that’s a black flag. Check your hardware. Typically the rear bumpers are ran fairly loose to help keep the kart free but over time this saws into the bolts and mushrooms out the washers. Check all the hardware and put some zip ties on there as well. You can also run a cable and cable clamp from the rear bumper to the frame to help keep everything on the kart if something does fail. Redundancy is your friend.
Losing a chain – Assuming the mount is tight as hell, the jam bolt is ran all the way into the mount and the chain tension and alignment is set this really shouldn’t happen. Think the engine is tight? Might as well check again. And if you lose the chain, throw it in the trash, it’s junk.
Axle set screws – Ever change an axle and go out and run dog slow? It’s hard to run fast when the axle is moving side to side and the brake is dragging. Double check those axle set screws, especially if you just changed the axle or are running a soft axle. They love to cave in a little bit and then the set screw is lose again. When I change an axle I always run a quick check list – hubs tight, chain aligned, mount tight, set screws tight etc. It takes an extra minute and saves a lot of headache.
Exhaust failure – It’s rare for an exhaust just to break with no prior warning. Check your can lid for any cracks, check your header for any cracks, check your flex and make sure it’s in good shape. Typically you’ll see some oil start coming out from a crack as well which helps identify an issue.
Bead locks – You just mounted new tires and now you’re on track and have a flat. Did you double check your bead locks? I’ve seen brand new wheels with dry rotted o-rings on the bead locks. It happens. Also check the valve stem to make sure it isn’t either torn or that the inner Schrader valve isn’t lose or damaged. A slow leak isn’t any better than a flat. You can spray a little Simple Green on each bead lock as well to see if you can see any bubbles.
Floor Tray Bolts – The floor tray bolts take a lot of abuse and we tend to ignore them. Over time you can grind an entire lock nut off the floor tray and then the tray can drop off the kart on track. Replace your floor tray hardware when it’s starting to look a little sketchy.
Wheel Nuts – If I only had a dollar for every wheel I’ve seen fall off a kart. Check your wheel nuts before you hit the track, especially if you just changed wheels and tires. Maybe you tightened 3 but missed the last one. This is especially important if you are thrashing and changing tires for the rain. No point in throwing on a quick rain setup if the wheels aren’t tight. Check the big spindle nut too!
Pills – Did you just change your front end setup? It’s easy to have castor in on one side and out on the other and not notice. This is especially true if you are running top AND bottom offset pills. Double check those bottom pills! They can be tricky.
Toe – Okay you just changed the front end but did you get those tie rod jam nuts tight? It’s easy to forget especially if you finger tightened them while you aligned the front end. It looks tight but is it?
Throttle – When was the last time you changed your throttle cable? Considering it’s less than $4.00, its cheap insurance to occasionally put on a new cable. Also check your throttle stop and make sure you are getting full throttle but also make sure when the carb is full throttle the pedal stop actually stops the pedal! I’ve seen a lot of bent throttle shafts that actually start to close again because of poor use of throttle stops. Don’t let it happen to you!
Rear Hubs – If the rear hubs are left loose it’s rare they actually come off the axle, if anything they go in which totally wrecks your setup. I like to run the inner plastic hub spacers on the hubs so even if the hub would slip it can’t go anywhere and my track width stays the same. You can run the hub spacers on 50mm hubs and some 40mm hubs if the hub hangs off the axle. If you are running a 30mm axle clean the axle and hub well so there is no oil for it to slide on and run a narrow strip of duct tape behind the hub. Typically if the hub moves it won’t go far. It also helps to get it tight as hell!
Seats – Make sure your seat isn’t cracked or ready to break through. It’s hard to drive a kart when the seat is falling out of the kart. Also check the struts on occasion. They can and do crack.
Airbox – Zip tie that sucker to the frame or the seat or use an airbox cradle! Also make sure your filter is in good shape. The boots can tear and the box will fly off.
Fuel Tank – If it’s a quick release tank check the knob. A lose tank flopping around the kart is a huge distraction. Also make sure the fuel line and filter are in good shape. The fuel line that goes down into the bottom of the tank can swell and start sucking air right at the fitting. I like to safety wire the line and fitting inside the tank. The line can swell so much I’ve seen the line just fall off!
Well I think that hits a lot of the highlights (or lowlights) of stupid things that can cost you a race. There’s always more but as long as you double check your work when you get done with something on the kart, change out hardware that is looking ragged and occasionally give the kart a once over you can avoid some of the most common issues. Distraction is a huge enemy. If someone comes over and takes your attention away from what you were doing then double check yourself after you get back to work. One lose nut or bolt is all it takes to ruin a great race.
source: Mark Dismore Jr. / Comet Kart Sales