It's Your Turn - To Screw

The Thread Spread

- It's Your Turn -

To Screw

The question - After installing Motion Pro twist throttle, my Blaster doesn't run like it use too. It cuts out on top end, more so from 4th gear on to 6th. Please bear with me on the following stupid questions. I put in a new plug "gaped" checked the air filter "brand new" and fooled with the idle adjustment. I also tried the air mixture screw. Now the dumb questions, 1 and a half turns is what the manual tells is right. That's one complete turn 360 deg.+180 correct? Also does more turns out lean the mixture? I don't want to fry the motor. Next "more jetting questions" Its 34 degrees out side could that be it? Don't worry I have a friend who's very capable of helping me with this, but I'm trying to wean my self from having to run to him every time I foul a plug.

The response - Correct. and no that's not dumb, I have to think about it too. Out is richer. Unless the carbs really messed up, you won't fry it with the air mixture screw. I have no experience with riding in low temps. Does not get that cold here except during a few nights a year. Now if you want to talk 117, can do. I don't have the owners manual on right now, but I think a jetting change is in order. The real question is if the twist is causing your problem. Did it work fine is the same weather conditions with the thumb?

YFS200

I don't know what carbs on that quad, but generally the low speed mixture screw is an air screw not a fuel screw. That means when you turn out the screw you are letting more air past the screw which makes the mixture leaner.

Your 34° temp is packing more air and must be compensated for by making the mixture richer - since you have more air you need more fuel - even though the fuel is more dense too. Start by lowering the clip to raise the needle which will richen up the midrange. Take it one position at a time. You may have to jet richer on top too. Make changes to the main jet in small increments. Usually 2 - 3 sizes would be about right for that kind of temp.

Rick

Back to The Thread Spread index of articles.

To Screw
The question - After installing Motion Pro twist throttle, my Blaster doesn't run like it use too. It cuts out on top end, more so from 4th gear on to 6th. Please bear with me on the following stupid questions. I put in a new plug "gaped" checked the air filter "brand new" and fooled with the idle adjustment. I also tried the air mixture screw. Now the dumb questions, 1 and a half turns is what the manual tells is right. That's one complete turn 360 deg.+180 correct? Also does more turns out lean the mixture? I don't want to fry the motor. Next "more jetting questions" Its 34 degrees out side could that be it? Don't worry I have a friend who's very capable of helping me with this, but I'm trying to wean my self from having to run to him every time I foul a plug.
The response - Correct. and no that's not dumb, I have to think about it too. Out is richer. Unless the carbs really messed up, you won't fry it with the air mixture screw. I have no experience with riding in low temps. Does not get that cold here except during a few nights a year. Now if you want to talk 117, can do. I don't have the owners manual on right now, but I think a jetting change is in order. The real question is if the twist is causing your problem. Did it work fine is the same weather conditions with the thumb? YFS200 I don't know what carbs on that quad, but generally the low speed mixture screw is an air screw not a fuel screw. That means when you turn out the screw you are letting more air past the screw which makes the mixture leaner. Your 34° temp is packing more air and must be compensated for by making the mixture richer - since you have more air you need more fuel - even though the fuel is more dense too. Start by lowering the clip to raise the needle which will richen up the midrange. Take it one position at a time. You may have to jet richer on top too. Make changes to the main jet in small increments. Usually 2 - 3 sizes would be about right for that kind of temp. Rick