Honda SGX Sky 50 - Fuel Problem By 1pkryan (Read 6,002 times)

[1pkryan]

Okay, so my previous thread was about this bike with wiring / spark problems...  I finally got hold of a stator and wired up the ignition so i can use the black-box, and i get a blue(ish) spark.

Problem now is:
I put a tiny amount of petrol down the head, on the odd occasion it tries to fire up with a sort of pop pop pop. Thought it would of fired up and ran at least until the petrol had evaporated. Though i could be wrong about this.

Thought i would try and run it the "normal" way, filled tank up and another problem was found.  Vacuum system don't seem to open the diaphragm and fill carburetor with fuel.  So i took all the carburetor apart cleaned it, but it didn't make a difference.  While taking it apart i noticed the float was touching the inside of the carburetor, on previous bikes i'm sure it didn't touch nothing, would this cause a problem at all?

Note: 
But if i suck on the vacuum pipe going into the inlet it does fill the carburetor.  So i proceeded to kick the bike over as the carburetor now had fuel in it, but still no start.  Where the carburetor fits to the inlet the inlet is bone dry.

Only thing i can really think of is something to do with the automatic choke, so really hard / impossible to start. Not sure on the problem with vacuum system not filling carb thought maybe compression, but if i put thumb over spark plug hole it blows it off.

Thanks.  =)

[1pkryan]

bump.

Okay i have it running now some-what, but it seems to be stuck on full throttle then it goes normal then goes full revs again... Needle don't seem stuck, tried adjusting idle screw while bike is running, no joy. Was forced to choke it with my hand...

Anything i am missing?

[JR]

If the float was touching the side of the carb it sounds very much like it is bent or for sure out of adjustment. It's starving for fuel. Did you make sure it was moving freely and did you adjust it where the bowl will fill but not run over?

JR

[1pkryan]

Hi JR, been a while.

Nope didn't touch the float, the height of it does seem out though. Others i've seen have a kind of spring-like touch to them. It's not touching the side, when i take out the carburetor and turn it upside down, that is when the float is touching the inside. Don't seem to be no overflow issues as far as i can see.

Did notice what looked like petrol but could be oil around the inside of the stator/magneto which might be an air-leak at the crank seal. Would this cause the erratic behaviour?

Might also need to find out correct screw adjustments for idle and air/fuel jets.

Thanks for the reply.

[JR]

For sure any air leak will cause problems with a 2 stroke.

[1pkryan]

Thanks JR.

Will take a look at it in a few day's and let you know the outcome.

EDIT: Forgot to mention when disassembling bits, i noticed there was no gasket for the exhaust and inlet.  Would these cause problems as well?

[JR]

Yes, with two strokers one needs everything tight and not leaking.

JR

[1pkryan]

Thanks, will get all these little bits sorted out, then get back to you with the results.

[1pkryan]

Just got my parts this week and fixed it today, seems to tick over and not revving it's self . Anyone know the correct screw settings for the carburetor?

Thanks.

[JR]

Try turning it until it bottoms out then turn it back out 1-1/2 turns and see how it does.

JR

[1pkryan]

Thanks JR.

Seem to have another problem... ( 1 after another.. ) When i rev the bike it will die with a burr like noise as if it's starving of fuel unless i stop revving then the bike will tick over fine again..

Any advice on this issue?

[JR]

Do you have a good tight fitting air filter on it? It could be a lack of fuel or too much air or both, try opening up the fuel adjustment a little more. Two very helpful 2T carb tuning tips:

thescooterprofessor.proboards.com/thread/3167/2-stroke-carb-settings

thescooterprofessor.proboards.com/thread/3002/2-stroke-carb-tuning

JR

[1pkryan]

Thanks JR.

I did try it with the air filter off at first, and then tried it with it on and it seemed harder to start with it on, and didn't get any easier with me me adjusting the air/fuel screw.

Should i be testing the auto choke make sure it is fully operational?  would this even cause a problem like this, just guessing.

I'll take a look at them links you provided and get back to you, thanks.

[90GTVert]

Did you make sure the main jet was clear/clean when you cleaned the carburetor? If the air box is off it will most likely need a larger main jet. You need a filter of some sort for street riding anyway, so I'd work on getting it to run with the air box installed. Check the air box out and make sure it's clean and has no cracks or missing screws or other damage.

It wouldn't be a bad idea to check out the automatic enricher.

Have you checked compression?

[1pkryan]

Okay, i did have it all running nicely but now it's like it wants to go but it don't move the wheel. Wheel is not locked can spin if freely with my hand.

Iv'e cleaned the carburetor out 2 times all passages and jets are clear so wasn't sure if my question below is connected and shorting something out or if it's normal.

Also quick question about spark plug boot, if i kick bike it makes a spark like noise without the spark of course is this normal or should it only make noise with spark when i hold it to cylinder head? Also Sparks when say 1 inch away from where the exhaust connects to.

Thanks for the all help so far.

[OFF TOPIC]:
jr
Did you find an english wiring diagram of that dutch diagram? Think i have found a english 1. Will upload if you haven't got/found 1.