New 48cc Skyhawk No Start

Brent436 said:

Back again guys,

Sorry i havent been on in a while, havnt really had time to work on the motor.

Thatsdax, i am getting spark I have already checked it several times. I just got my new NGK B5HS plugs in and have put one in. I tried starting it and it is even closer to starting than the champion plug i had in it. It was running for maybe 3 seconds but once I disengaged the clutch it died almost right away. It is firing a lot and like i said in an earlier post, the cylinder and exhaust are actually getting warm because its firing so much. Its on the brink of starting.

I took out my carb jet and theres nothing blocking the flow of fuel. I took a few pictures.

Any more help would be appreciated. Thanks

-Brent

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Have you checked the float needle seat this is the first place it will block up, also what does the plug look like?

Well this is a puzzle, i think the fact that it pops at all would say you have spark so really its just down to fuel or a lack of it.
checking the plug condition is really the only gauge as to whats going on in there.

In the third pic you posted you see the brass horse shoe thing if you remove its locating pin the float needle and seat is under it, or above depending on how you look at it, make sure that tube is clean and clear.

Are you still running the petcock filter? (hilarious name) thats the thing fuel tap thingy there is a filter behind that and the tank, i think its there? unscrew the petcock from the tank, that can get blocked from stuff in the tank best to ditch that filter and use an inline filter between the petcock and the carby.

Also not sure if you did it but the inlet manifold gasket has a really small hole did you make that bigger to match the port. that could maybe cause a prob.

Silly 1 but happens to all of us at 1 point, have you got the choke lever in the right position? down is off up is on.

Killswitch? ahh i dont wanna go there, double check your wiring?

Are you opening the throttle when it pops? Positive the carb is together correctly?

Brent - I've had... ongoing fuel starvation issues with my Schwinn, part of the reason is the angle at which the carb is at not allowing the float a full range of motion.

Yet usually that doesn't matter so much as I've bent the float tabs and took 1/16" off the tip of the primer pin (as the carb is canted slightly w/the pin on the low side), it only starves at extended (very) high RPM & WOT now, prolly just as well as any longer spent in that range and I'd blow it up lol

Still, as I've had 2 different carbs on it (both stock but one old and the other new style), 3 different petcocks (seals keep dissolving w/the new "gas"), half a dozen filters, and two different tanks (first developed a leak). This may sound excessive - but I've well over 4000mi of relentless abuse on it now so some maintenance is to be expected heh

As my build is persnickety, I've very little room and the carb has to be "just so" I tend to remove and discard the in-tank screen and run without a filter at all to determine if the carb itself is set properly, then install the filter (in-line metal mesh). This eliminates the "guesswork" and I've found that sometimes an old petcock was the culprit, sometimes it's the filter - even new it seems some are more restrictive than others, I had one new one that was more restrictive than the (lightly) used one I was attempting to replace.

Last but not least - I found the newer style stock carb problematic as the secondary petcock on it's side was not only restrictive (the passages very tiny) but the small O-rings quickly turned to goo, while your ride is still too new to be suffering from the ethanol effect yet, if you've the newer style stock carb - you may wish to bypass that second petcock in your attempts to diagnose.

Sadly, I've no idea if your suffering starvation issues, actually I'm not sure you are as it'd still start and run till it was out of fuel in the float bowl - but I thought I'd share my... trials in an attempt to help

The only thing thats a pain in the butt is the fact we cannot figure it out yet, but we or you will.


both paper and steel!
Carburetor, Fuel & Air
have only used the paper never had a problem i keep em on for about 2 months then replace, though i ride everyday.
Any flow is good but if i undo the fuel line from my carb the fuel will be a steady stream to the ground, not drips.
Set the carb Nut by adjustng nearly all the free play out then tighten the nut down. remove the air filter and check that the throttle slide goes all the way up and down to where ever your idle screw is set.
With the killswitch try it without, wire black to black and blue/green to blue/green and tape up the white wires exposed end.

i'd go back to the beginning, and start with the basics.

you know you've got spark. make sure it's dry and gapped at .025-.030.

you say the plug was wet so you have fuel. undo the fuel line at the carb and turn on the petcock and make sure fuel's coming out.

hook the fuel line back up, turn on the petcock, and see if your carb fills up. undo the float bowl drain screw on the outside and see if fuel trickles out.

if so, fuel's good. if not, fuel's clogging.

with the air filter off, look into the throat of the carb, twist your throttle, and make sure the slide raises up all the way. also, make sure when you start twisting it, that the slide moves at all. if not, adjust the barrel that the cable goes into at the cap on top of the carb till it does.

now, screw the idle adjust out 3.5 turns. look back inside the carb and screw it in some more to make sure it's raising the slide a tiny bit. then unscrew slowly till it doesn't lower anymore. ideally, you want to find the spot where the slide just starts to move up.

assuming fuel and carb's all good, check your wiring. i don't know which colors you have, but someone here does, i'm sure. make sure all connections are tight. i'd leave the kill switch disconnected and taped up so it doesn't short out until you get it running. also, make sure your plug wire is screwed into the CDI box all the way. it looks sealed, but it's actually just twisted onto a screw inside the box. twist it clockwise to make sure it's tight. don't overdo it. also, make sure it fits tight on the plug itself. with the stock wire, you know you have to unscrew the little nipple off the plug, right? should be just threads on the end of the plug.

so we have spark, fuel, and wires.

it's clutch time.

push your bike forward without pulling the clutch lever and make sure the wheel skids. now pull the lever, and make sure it doesn't. it's more or less that simple. if the wheel moves without pulling in the lever, you need to adjust the cable looser.

the basics are now covered.

pull the choke lever up, push the tickler a couple of times, pull in the clutch and pedal away. dump the lever, don't just let it out, and keep pedaling, and give it some throttle. if it doesn't start the first time, try again. and again.

if it kinda starts, then dies, try half choke.

if it's still trying, screw the idle adjustment in another half a turn, this'll give it more throttle.

when you're starting it, always keep pedaling. my bike sometimes takes 15 feet of hard pedaling, and sometimes starts with a nudge

now, if it starts, pull the clutch lever in and keep revving the throttle. if it's revving really high, unscrew the idle adjuster a little till it sounds good.

if it's still revving high, your throttle cable's too tight.

(edit) if it starts, remember you don't have a kill switch. hit the brakes and dump the clutch to kill it.)

if none of this works for you, send it back.

Yeh! what he said.

did i leave anything out? i didn't intend to write a whole "how to start your bike" essay, and i was actually kinda drunk at the time, but it came out all right...

the idle screw should be adjusted like that. turn it all the way, then back it out 3.5 to 4 complete turns. or do like i said and watch the slide from the air filter side till it moves.

as for the throttle cable, do the same. watch the slide as you twist the throttle. you just want a tiny bit of play to start with as you turn the throttle before it moves up.

leave the barrel adjuster on top of the carb loose, and when you get it started, first try the idle screw, screw it either way to try to get it to idle. if not, screw the throttle adjuster up and down. it's pretty simple once you figure it out.

oh, and the choke. usually i only need it on for 10 or 15 seconds. if you can keep the bike running long enough to warm it up, move the lever all the way down so it's off. you don't want the choke on at all when you're adjusting it.

and, congrats...

try dry the conection to the cdi ive found if it just wants to start but wont there usily it

another satisfied customer...

Brent436 said:

Yes, I am very satisfied and am feeling that I am finally getting my moneys worth. I've already made multiple short trips around town with it to help break in the motor. It has plenty of power to get up hills (pretty steep around here) and really just cruises right along pretty smoothly.

This has to be the best forum site i have ever seen as everyone is very friendly and helpful. I will continue to look around the forum to see what everyone else is up to, and to maybe even help someone who is in the position i was just a few nights ago. I know that if I ever have anymore problems with my bike, I will definitely be coming here for help.


Again thank you everyone for your help,

-Brent

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I wish I could say the same dude,