Fuel Starving? By dn3616 (Read 7,382 times)

[sprocket]

Sure.. need to know you have a gravity feed or fuel pump...if the tank is above the engine it is a gravity feed...below the engine it is a fuelpump...

You should test the petcock before you buy one...do a search here on the forum...also your problem could be electrical...hard to say...

[dn3616]

right a bit of extra news. I finally got some money together, and have bought a new carb, air filter, and a new fuel filter. All of them brand new and have also installed them. Before i had these parts the bike has been runinng the WORST its ever been. For some reason, i cant seem to get past 20-30 mph, even on flat! Going uphill im going a good 10-15 mph. The bike right now, is unrideable.

I dont get whats wrong. I also think for some reason, when the engine is off, fuel is still flowing through the lines for some reason, cause i know before when ive tinkered with the bike, the fuel will only flow if the engine is on and the vacumn is sucking the fuel through the petcock. Has my petcock failed and will need to get a new one?

ANy advice wil be great guys!

[Bashan]

Did you ever loosen your gas cap to see if that did anything? Also, try running a line right from the tank to the carb. That will bypass the fuel vac valve and take it out of the equation. Your float mechanism should stop the gas flow, the vac valve is really just a safety device. Then, if it's still doing it, plug the vac line from the vac valve to the intake manifold to make sure it's not a vac leak. Rich

[dn3616]

I did try it with the gas cap off on a sunny day, but unfortunatley it did nothing :/ im trying everything i can atm, and its just annoying how it doesnt work! So should i run the fuel line from the carb straight to the petcock? and then plug the vacumn line from the petcock to the carb?

[chadlawson]

Hi guys, I'm new and I was hoping someone might have some ideas for me. I just replaced my fuel pump, lines and carb but I can't get it to turn over. Everything has a tight seal. I was wondering if I need to adjust the screw next to the line in to the carb? Please help... frustrated...

[Alleyoop]

DN3616,
Have you adjusted your valves? Seeing as you have some miles on the scoot they could be getting tight after it gets hot. Also check if the Petcock Vacuum line is allowing fuel to flow and that would cause it to run rich. So take the Vacuum line off going to the Petcock and if it is wet then you need a new Petcock.
Alleyoop

[Alleyoop]

Chad,
Start a new thread with your problem otherwise your problem will get lost in this one. And I will go and help you there.
Alleyoop

[Bashan]

Aug 5, 2012 10:36:38 GMT -6 dn3616 said:

So should i run the fuel line from the carb straight to the petcock?

No, run it from the tank straight to the carb. This will BYPASS the petcock and see if it is the problem. Just leave the vac hose hooked up to the petcock for right now. Hey, your petcock isn't in the bottom of the gas tank is it? Rich

[Alleyoop]

Rich has a good point, is your petcock on the Gas Tank. If so those petcocks have a Filter attached to them inside the tank, and the Filter could be clogged.
Alleyoop
They are all Vacuum Operated except the Fuel Cutoff types, which or off and on.

This type screws onto the tank itself and has the filter tube:


This type a hose from the tank connects to it and has no filter.

[parkrider]

Clogged pet cock filter is exactly the line i am pursuing now for the issue of my bike losing power at wot especially up hills with the red head on the back.

tho a new cdi made a world of difference in the purr of the engine, but did not fix wot issue.

one of the fears that introduced the petcock to the whole system by designers,,, i am told,,, was fear the gas would fill the combustion chamber while parked if the float failed.

As well, there is a guy who swears his petcock diaphragm dissolved and sent gas right down the vac line to engine.

WOW!

[parkrider]

Jul 14, 2012 9:31:12 GMT -6 sprocket said:

I don't think Chinese scooters are snitty...actually for the price, they are great! Have you completely flushed the tank and fuel system? Cleaning the carb, does nothing you need to clean the system and replace the fuel filter...sounds like the petcock, or fuel pump...check you vacuum lines.

I found today, as I put in a new petcock on my gravity tank yet a second gas tank breather EPA device way up back in the plastics.

This being right on the breather tube.

like a PVC valve, or what the plumbers would call a "Stop Back Flow"

this lets air in but not out to stop/contain gas fumes for those new to this.

WHAT IS AMAZING to me is this is the second one I have found, the first was on/part of the whole EPA canister that had a few different functions including that of doing god knows what to the head exhaust.

When i tried blowing thru it -IT WOULD NOT LET AIR THROUGH ON EITHER SIDE.

So I Stomped it with my foot.

I put in a new long hose to breather on top of tank , with a gas filter on the end.

THIS OLD DEVICE WAS DEFINITLY CAUSING VACUME IN THE TANK and thus restricting fuel to carb.

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[dn3616]

H guys just a quick post.

I havent been able to do much with my bike recently cause of work and everything, but i realised that i was wrong about the fuel constantly flowing through the fuel line. It does stop the fuel flow once the engine is off. Also, the vacumn line was not wet at all so it doesnt seem that the petcock has gone.

Ive been doing a bit of research too and ive ready that 'low compression' could be the case of the bike not being able to accelerate properly and also hills being basically impossible to do, which in my case is correct.

When i get chance, i will check my valves. havent done them in a while so will have a quick check.

I havent riden my bike since last sunday and im not willing too tbh, as i know my bike still isnt working right. Also, my bike starts AMAZINGLY well now, i started her up yesterday and she fired first time!

Its just annoying how she will start amazingly well and will have power and not when im riding her.

Also, is there any reason why my bike on the stand, will accelerate preety well and then not once i am on the bike?

Thanks for all the help so far!