GY6 150cc baja dune HELP!!!
 

I have a Baja dune 150cc that i found in a field and i rebuilt it, only problem is that when i go to start it, it'll start idle for a few seconds and then die. When i do get it to idle it will sputter and die whenever i give it any throttle. It has been bugging me for a while and i cant figure it out at all, i bought a new carb, new CDI, new coil and it still acts up. PLEASE HELP!!!!:(:(:(

Turn off fuel Disconnect fuel line from carb , place line in coffee can and turn on fuel, see if you have a continual flow of fuel or just a drip. Could also be a bad stater, I think you covered every thing else. On second thought, how does the exhaust sound? Could it be plugged? Could the intake be plugged? Did you leave a rag in the air cleaner or intake port?
I have seen it before.

i have a new exhaust on it and it sounds very good (when it runs) but i checked the stater and it powers up fine last time i checked, and as for the fuel im getting a nice steady flow. Could it be too much air rushing into the carb to the point to where it basically smothers it???

Another thing, how old is the fuel? Fuel can do some strange sh#t.

it has new fuel it it, ill take out the stator and bench test it this weekend just to be sure though. Thanks for the suggestions i hope they work lol

I'm no expert on these, however I did stay at a Holiday in last night, I have been a mechanic most of my life, Im 61. Will it stay idling? If you put your hand partial over the intake will it stay running, if you and open the throttle will it rev? If so your jetting is to lean. Also if i'm not mistaken many of these engines use a separate winding in the stater for the ignition, powering up may have nothing to do with the section of the stater that powers the ignition what does the spark look like? is it crisp and blue or weak? Put a screw in the spark plug wire and hold it an eighth of an inch from your spark plug and start your engine, is it crisp and blue?"Could it be too much air rushing into the carb to the point to where it basically smothers it???"To much air and not enough fuel is a lean mixture, (jetting to lean.

Before you take it apart, check the color of the spark, if its blue and crisp when it sputters and dies then don't bother taking out the stater. Do the old hand over the intake trick to see if its way to lean.

i cleaned the stator and its all working properly, as of right now i dont have an air filter on it, when i put my hand over the intake it runs a little bit better, when i give it throttle it just bogs down like it always does so i have no clue whats going on. im thinking maybe i just need to put high test fuel in it and run the darn thing like a mad man and hopefully it clears things up.

What size jet is in the carburetor?

I have seen many that the trick is if you can get it to fire and idle, just don't touch the gas for a minute or two until that automatic choke comes off. Some are just pigheaded. As it warms up ever so slightly you will be able to feather your way into the gas pedal a bit more.

I can get it to idle but only for like 20-30 seconds, you thinj i should adjust the air/fuel mixture screw?

And it is stock jetting, i live in pasadena maryland so my elevation isnt too high

Check fuel flow at the drain on the bottom of the carb. Engine off, fuel shut off open, open the drain, drain into coffee can, see if you have continues flow, or if it slows to a drip. This could be your problem. Float level to low or internal problem in carb.

Stock jeting for what? 90% of the carbs on the internet are jetted foe a scooter, you need to know what size jets are in the carb.

Jetting may well be off, however it will run for twenty or thirty seconds and then die, if jetting was off that far I doubt it would run that long, and if it did choking it with his hand would keep it running, check fuel flow at drain.

So it continues running when you cover the carb with your hand? You said it runs better when you do that also? Tried spraying carb cleaner or starter fluid around the intake yet while running?

deja vu to my wife's reaction. try holding the key in the run position. switch may be bad. My wife's would half-click back after a few seconds of running and cut off. also when i did get it to run, the vibes from revving would also knock it back. drove me bonkers chasing all the areas you're chasing.

Yup that would drive you nuts, Had a friend with a Model A, Jag running gear thermal glass webbers on a small block, no bolt with out chrome, first class, he was convinced that the webbers were causing the engine to die when he stopped fast. Long story short, he had the starter chromed, when it went back together parts were loose in the solenoid, that were able to slide forward when he stopped hard and shorted out the ignition.

have you done any work to it? I ported the head on mine and did other work to it, it was too lean then, It would be ok if I half covered the intake went from a 35 to a 38 pilot and now it runs great, sounds lean

Did you ever properly adjust your rocker arms? They go out of adjustment in about 500 miles. Also the jam nuts can work loose and the adjusting rods start backing out. If they get really loose the motor will idle but dies when throttle is opened. Check that out and post your results.:drive:

When you rebuilt the engine, how did you adjust your valves(hot or cold?), and what lash did you set them at?

I just wish you lived closer, it would be running in an afternoon.

I fired it up today ( march 20th ) and it wouldn't idle soni stated it and instantly floored it and it coughed and then kicked in and ran like a mofo, i have a A10 cam innit, performance exhaust and a racing cdi, im thinkong its way too lean. I also have a K&N air filter on it, should i get bigger jets???

If it has the stock jetting, definitely yes.

what sizes should i get then?, i'm not familiar with small engine jets, only cars.

I would start with a .125 then go from there after a full throttle run and plug reading.

Thats the pilot jet right?

Main jet

I think he means 1.25 mm Main Jet, Have you tried backing out the idle mix screw? The other thing is, is the jet plugged? a .35 to .45 idle jet may be appropriate.

Are you sure that you don't have a manifold leak? Try starting it and squirting carb spray around the manifold base and carb connection. As for jetting, check jets by holding them up to the light to see if there plugged, you must see a clean round hole, not just light but a clean round hole, Jetting sizes are in metric, idle may be .35 mm, one mm is very close to .040 in" so .35 X .04"= .014 in or 14 thousands of an inch. a main jet may be 1.25 mm that = 50 thousands of an inch. If you have a micrometer and a set of wire drills you can check and change your jetting.

Here is a link that should be helpful. http://battlescooterstore.com/epages...uretor_Jetting