air flow effect on engine performance

[dzdaz]

Is it always going to be neccessary to reach down and adjust the choke/air intake while riding at different speeds or is this just during the break-in of the engine? I noticed that my engine bogs down a little when I have the choke closed a hair too much, and I get more top end speed if I move the lever to all the way open(down)the closer I get to full throttle. Or if I have the lever down, it bogs out if I'm barely on the throttle. Is there any way to get it to run smoothly thru-out the whole range of throttle without constantly reaching down and making adjustments to the air intake?

 

[gone_fishin]

basic consensus seems that the choke is only needed during starting...you might want to check the carb-to-intake and intake gasket...sounds like you may have a leak...?

edit: or...maybe the idle's too low?

 

[dzdaz]

?

So after starting the engine the lever should be all the way in the down position or right in the middle?

 

[etheric]

After she's warm you shouldn't need the choke at all. So the lever would be in the fully down position. In fact, I haven't had to use the choke much at all unless it was particularly cold, and even then just a bit, midway at most.

 

[davidsis]

Air

If you have to have the choke a little bit closed then you probably do not have enough fuel in your mixture. Turn that little screw on your carberator out giving it more fuel. you do not have enough fuel and that is why you need less air. Turning that screw out will make your mixture more rich.

 

[Blaze]

Please note that not all carbs have mixture screws. Most of the carbs only have one screw, and it's only for the idle. Mixture is usually only adjusted on those carbs by moving the E-clip into a highler or lower groove on the throttle needle inside the carb.

We have a lot of people in this forum who are trying to adjust mixture by turning the idle screw. I think this might be due to the fact that some carbs do have mixture screws and some don't. Mine does not.

 

[Blaze]

Post a photo of your carb from both sides and I will tell you if it has a mixture screw or not.

 

[dzdaz]

i think the screw on mine is for idle speed

i'm pretty sure the screw on the left side of my carb is for the idle. how can i check the intake and gasket for leaks. When I have the chke lver totally down it runs great closer to full throttle but I have boggy bottom end. i read someones post on here that mentioned the black clip washer in the thottle needle having something to do with this prob. heres a pic of the left side of my engine. its a bell howell 70cc i got from dascommm on ebay.(thatsdax?)

 

[dzdaz]

? now?

 

[gone_fishin]

yup, your side-screw is for idle only.

best bet on mixture: using pliers and needle-nose...take the carb slide out, diassemble the needle/e-clip, and try each slot on the needle til you have your best performance. it can be done while the engine is hot and it only takes a minute to try each setting.

keep us posted on how it goes