I have a kinda new bgf engine with about 50 to 100 miles, and it is kinda idle up and down not really to high up but drops down sometimes low enough to die but the idle screw is working right..That my question how does it drop down enough to die I don't get it.I also know it's still in break in.Just any idea's what to get the idle stable.I thought maybe air leak but I think I tried every thing to find one.
break in question
- Thread starter wan37
- Start date
crassius
Well-Known Member
Might be the clutch sometimes dragging a bit which could go away when it runs in some more. You might be able to adjust it for more clearance when pulled.
If not the clutch, I try lifting the needle one notch for a while, then dropping in one from where you started to see if either of those will help.
Doesn't sound serious tho for so few miles.
If not the clutch, I try lifting the needle one notch for a while, then dropping in one from where you started to see if either of those will help.
Doesn't sound serious tho for so few miles.
biknut
Well-Known Member
I wouldn't worry too much about it till you get it broken in a little more. You need to start running regular mix ratio and then tune it. At least 2 gallons from new.
China girl motors whether 50 or 80 usually like the needle clip in the second from the top position for NT carbs. You'll also probably have to go down one or two sizes on the jet. 68 or 66 is usually about right..
A NGK BP5HS or B5HS is a good cold weather plug.
China girl motors whether 50 or 80 usually like the needle clip in the second from the top position for NT carbs. You'll also probably have to go down one or two sizes on the jet. 68 or 66 is usually about right..
A NGK BP5HS or B5HS is a good cold weather plug.
nightcruiser
New Member
I had some idle issues at first too... I also recommend you not worry too much about it until you complete the break-in on the motor and start running a standard mix.
Couple things that haven't been mentioned here yet, an air leak could cause your idle to be erratic. You want to make sure the intake/exhaust manifolds are air tight at the jug, and the carb isn't leaking where it mates with the intake. Also, sometimes drag on your cables can cause your idle to change. You should put some light weight oil down in your cables to help them pull smoothly, and make your cable runs smooth and sweeping rather than tight and bending. If the cables are too tight when you move your handle bars it might cause the clutch to drag and bring down your idle or might make your throttle move. Finally, when my float was set too high I had problems with the motor dying when I hit bumps while the motor was idling....
Couple things that haven't been mentioned here yet, an air leak could cause your idle to be erratic. You want to make sure the intake/exhaust manifolds are air tight at the jug, and the carb isn't leaking where it mates with the intake. Also, sometimes drag on your cables can cause your idle to change. You should put some light weight oil down in your cables to help them pull smoothly, and make your cable runs smooth and sweeping rather than tight and bending. If the cables are too tight when you move your handle bars it might cause the clutch to drag and bring down your idle or might make your throttle move. Finally, when my float was set too high I had problems with the motor dying when I hit bumps while the motor was idling....
Thanks nightcruiser that make a lot of sense I will check the cables and look some more for air leaks.I just have had a terrible time with this engine kit from new.First I had a seal bad and leaking on magneto side ,second had intake stud stripped and acorn nut are worthless replaced.Then got that done and fuel wasn't flowing right and wouldn't run at all then it would start and die and start run for a bit and die gas cap wasn't vented right drilled a hole and it all help.Then it had a air leak around the carb to intake so I put a o ring in it and seal all adhesive around the intake to fix that leak.I really don't think I have another air leak but it idles like I do up a little and down.I also know that is runs good riding but just that dam idle thing is got me stump.So all you guys help is useful a appreciative.
Groove
New Member
I agree with Nightcruiser. Does the twist throttle feel kind of sloppy? I resolved my idle issues by adjusting the throttle cable. In my case, there was too much "play" which rendered the idle screw adjustments useless. I added a small spacer (plastic drywall mount that I cut to about 1/4" - perfect diameter, same as the cord, I got lucky!) which effectively extended the length of the cable's outer cord. Now my throttle assembly just seems better "tighter". Plus....no idle issues..
nightcruiser
New Member
It has also been my experience that the inner cable for the throttle has been a bit long, leaving a little play when you let off the throttle, I don't really see how that would hurt the idle or render the idle screw useless though? The slack should actually help normalize the idle and let the slide seat down on the idle screw easier I would think. Remember, the idle screw just physically bumps up against the angled section of the slide propping it open a bit, the more you screw it in the further it is propped open. Now, if your inner cable is a bit short, or has a lot of drag, it can keep pulling on the slide after you let off the throttle and prevent the slide from ever seating down on the idle screw, rendering it useless. (idle would be abnormally high)
If your cables are well lubricated and routed smoothly your throttle should snap back to home position pretty easily, and the effect on your idle from turning the handlebars should be minimized or eliminated completely. I upgraded my outer cable housings with ones that have an inner lining (from a bike store), this way the cable doesn't rub against the spiraled metal inside the cable and cause drag. I also used a few flexible "noodles" on the throttle and clutch cables, you can find them on Amazon and elsewhere. They are kind of like little goose necks that allow the cables to make bends more gracefully with less resistance.
Also, another way to get rid of that extra slack in the throttle cable is to shorten the inner cable. It can be done easily with electric soldering tools (or even a torch lighter). You just need to relocate the ball end that goes into the slide up the cable a bit. I wrap a little bit of small gauge solid core wire (like telephone wire) around the cable where you want the new ball to be, then solder it in place with regular electronic solder. Leave a ball about the size of the original ball end, you can cut/file/trim with manual tools or shape with heat. I have never had one let loose on me yet....
I think it might be the throttle cable too.I will be taking the clutch and throttle cables off this winter to straighten the cable mess on the handle bars.I know it will help the Idle from droping down where it dies.I will try to shorten the throttle cable that will help.Groove and night cruiser I have read your post a few time and will try the phone wire thing sounds easy enough,Thanks guys
Last edited: