Airbox -A/F Mixture relation

if we set the a/f mixture without the airbox connected to the carbs and after setting if, we connected the airbox back. is there a difference? we need to warm it up for about 10mins average until it runs fine. is there another problem. its a maxim 650.

 

Yes...the airbox/filter decreases the amount of air available to the carbs, down to NORMAL. By setting the air/fuel mixture (how did you do this, btw...colortune? sound?) without the airbox on, you set it too rich.

It does need to warm up a bit before it runs as it should....what problems are you experiencing prior to the 10 minutes?

 

hi,

we just started out with bigbikes. this is our first bigbike. what i meant when i said that we set the a/f mix is just turning the adjustment screws while the bikes is idling.

in the 5- 10 minutes. when we turn on the bike, we need to grab the throttle a little bit so it would not die. it runs really bad and idles bad. when i twist the throttle, it will sound like its gonna die. so i'll just let it idle at a slight grab for about 5 to 10 mins and then it runs fine and great.

 

There are two different carb adjustments (actually three) that affect the way these bikes run, warm and idle.

The carbs have to be synchronized, vacuum-wise, using some form of manometer. The YICS (if your bike has YICS) needs to be blocked off for this also.

The mixture screws won't get you anywhere if you're out of sync.

The third adjustment I mentioned is the float levels in the carbs; if one or more is too high or low, it will exhibit most of the symptoms you describe.

HOWEVER: It does no good to try to get your carbs set up correctly until they're clean clean clean, and you've checked the valve clearances (and adjusted if necessary.)

 

There are two EASY adjustments you can possibly make to your carbs without needing any tools RIGHT NOW.

First...there are two sets of screws on the top parts of the carbs. The pilot mixture screw (what you might call the a/f mix screw) is on all 4 carbs and you can (likely, some are still plugged) see it by looking at the top of the right most carb without taking anything off your bike. The second set of screws are bigger, not actually on the carb body but between them, and you don't want to touch those, yet. They are the sync screws. If you have touched them, let us know we'll tell you what to do.

Second...the idle speed screw is in between the two middle carbs, near the bottom of the carbs, forward of the carbs....you can see it by looking through the bike down low. It has a relatively big knob, not hard to find.

Since you messed with your pilot screws (a/f mix) you now need to reset them....that's not a step you can really do without a lot of experience or a special tool. GENTLY turn all four of them all the way in...not hard, just till they stop. Then turn them all out again 3 whole turns. Let them be.

Then, start your bike, do whatever you need to do to get it to warm up. Once it is warm, set the idle screw on the bottom so the bike idles at 1000 rpm.

If you still have problems, and you likely will, you can proceed the hard way or the easy way.

Hard way....don't take your carbs off and don't clean them.....try to sync without cleaning them....try to sync without checking your valve clearances...you'll be in for a world of hurt....

Or the easy way......um, RickCoMatic...I know you're out there, can you copy and paste the easy way here? I know you gots it handy.

 

@bigfitz and day

thanks for your replies.we will try your suggestions. i could have a video of the bike starting up so i could let you see it.