Can someone tell my why I have to have my airbox lid on to start my quad. And after it starts and I run it i take the lid off and I loose power and it doesnt run well.
Airbox lid
- Thread starter DOERR
- Start date
Sounds like your jetted too lean. When you remove your airbox lid you let in more air so you need to jet accordingly. more air needs more gas to keep a good A/F ratio so you need a bigger jet to run right.
Well this is wierd. It is a small 28mm mikuni carb that had a 140 main and a 17.5 secondary. And it just flat wouldnt run longer that 2 seconds. So, I put a 230 main and a 30 pilot and it runs and idles now but only with the lid on....You still think too lean?
yea 230 is with the lid on stock, its for sure lean. The lid makes a big difference when jetted right. Not sure maybe try around 260 or 270 main. A plug chop is the best way to tell though.
I should have said my mods aswell. 40 over full paul turner pipe and silencer, rad valve and new rad valve reeds. and this oddly small 28mm carb.
god, it's been 20 years.... I do remember running a 300 main in a bike with pipe, stock carb, minor clean up porting and no airbox lid. it was a custom pipe though, because the blaster had just came out and nobody was making a pipe for it yet. before you start with the main, go up one with the pilot. set your air screw 1 1/2 turns out. it should start easier, use the choke when cold.,. easy way to check the pilot, get it running without airbox lid, turn the air screw in 1/4 turn at a time, then let it idle a a minute or so to react. as soon as the idle smoothness starts changing for the worse, back the screw out 1/2 turn and your done. it should start fairly easily now. next raise you needle 2 clip positions, start the bike, let it warm up, go for a quick ride, running from idle to wot, is it smooth?? (do not run at wide open throttle..you are slowly rolling the throttle on to see how it accelerates) if it totaly cuts or if it falls flat on its face of feels to 'zingy' the needle is lean raise it somemore..if it's 'lazy' and cant seem to clear it's throut lower the needle a clip. once both of thoase are done then work on the main. make 1 change at time!!!! check 1 circuit at a time!!! do not make more than 1 change!!!!!! be nice to it untill it is dialed in.
