2008 Robot (actually Jonway YY50QT-T20)

[kalidasa]

Folks,

This is the scooter I own a 2008 Robot by Jonway (http://tinypic.com/m/hrin2x/1).

It has been sitting outside for over a year now. I had started the scooter last fall, added stabil and let it run for quite sometime and winterized it.

Earlier this year, in jan/feb when the weather was fine, I took it out to check if it would start - It would start but if I gave some throttle would shut right off...I gave up disappointed.

This past weekend, I gave it a nice wash and did the following:

The battery was dead - I had a backup fully charged.
The tank was drained
The fuel filter (or charcoal canister?) was replaced
Took the carburettor out and using carburettor cleaner (spray) sprayed most of the innards of the carburettor...enough to ensure there was no remnants of the old fuel. I dont enough to explain what are the things I cleaned
I put it all back...
I tried to start it. No luck. It would just crank but not come to life.
I removed the air-intake filter and sprayed some starter fluid and kept cranking...it would start and die down soon after.
I removed the spark plug, cleaned it thoroughly...and checked for spark (crank and bring the plug close to the body and verify there was a continuous spark.


One thing that bothers me is the line that comes out of the fuel tank (at the top, see this picture (http://tinypic.com/m/hrin2o/1) where to the right of the fuel cap is the golden metal flange securing the gas tank and right next to it is a line - what line is this? where should this go? when I opened the cowling, this line was all by itself, connected to nothing.

Also there is another line that is connected to the air-intake pipe...this snakes its way up - strangely, this was not connected to nothing...

If you see the picture closely, I duct-taped both these lines (sliding one into another)...

Other than this wonky arrangement, I did everything right.

My questions are, what are those 2 pipes for? Am i missing a part?Any pointers in why i cannot start the scoooter?

any help appreciated.:thanks:

[inuyasha]

Hi
Welcome aboard
Pleased to meet you
Hard starting is a symptom of improperly adjusted valves on a 4 stroke engine , i would try setting them properly and see how that goes
http://www.youtube.com/watch?v=s0K-ytyjOFg
Take care and ride safely
Yours Hank

[kalidasa]

Hi Hank,

thanks. My engine does not look like the one in the youtube video...where I can I find that valve?

Also, can you take a look at the 2nd pic I have linked...there is a line that comes from the top of the fuel tank and goes into a black square shaped thing(I dont know what it is) and on the other side of this black thing is another line that comes out...this line was hanging loose by itself.

Interestingly enough, there is one more line from the intake-manifold (visible in the picture that starts below the yellow fuel filter and snakes around its way to the top). I dont know if you can see, but it goes to the black thing (thanks to my engineering)...i connected the 2 pipes together with some gorilla tape. What is the function of these pipes?

[Firehawk989]

The one from your intake manifold should go to the vacuum petcock. The vacuum from the intake causes the petcock to open, allowing fuel to flow to the carb. To check if you have it connected properly, disconnect the fuel hose from the carb and crank the engine. If fuel comes out of the fuel line while the engine is cranking, you're good to go, and I would move on to checking the valves. Or it's also possible you didn't clean the carb well enough.

[kalidasa]

Thanks firehawk - here is my confusion:

I have a tank mounted "VACUUM OPERATED FUEL VALVE PETCOCK " (11th item from top, http://www.scrappydogscooters.com/COMMON_PARTS.html).

The vaccum line from the fuel valve goes to the carburettor.
The fuel line goes from the fuel valve to the fuel filter and from the fuel filter goes to the carburettor.

Yes - I have verified that fuel comes out of the fuel line when the engine cranks. I removed the line from the fuel valve to the fuel filter and when the engine cranked, fuel spurted out of this...also, the fuel filter (the yellow in 2nd pic above) is full of fuel...meaning there is enough vaccum to suck air out of the fuel tank...

One thing though, the spark plug was dry throughout hundreds of attempts to start the engine - Does this mean that I need to check my float bowl (I could drain the float bowl to check presence of gasoline in the bowl without taking out the carburetor, right?)...I watched this great video (http://www.youtube.com/watch?v=-2NIDcqv59I) to educate myself.

If there is fuel in the float, then the next question to ask is if the master or primary jet is sucking the fuel out of the bowl - How do I check this?

Is there a manual test for checking enough vaccum in the carburettor?

Are there any other vaccume leaks I need to check for?

[kalidasa]

oh btw, given that fuel and vaccum lines go to the carburtettor - I still dont understand the line coming up from the top of the gas tank and going into the black circular thingy with 4 holes (right above the yellow fuel filter Click me (http://tinypic.com/m/hrin2o/1) - what is this?

What is the line that is coming from the top of the intake manifold - should this go somewere?

As I mentioned earlier, I connected these 2 together, not sure if I should.

[Firehawk989]

Yes, check your carb bowl to see if there's fuel. Dry spark plug = no fuel getting into cylinder. If the bowl has fuel in it, one or more of your jets is probably clogged. The last carb I cleaned out, I used carb cleaner spray and sprayed it through all the jets and openings in the carb using the small plastic tube that fits on the spray nozzle.

As for those other tubes, sounds like some sort of funky emissions control stuff, maybe to scavenge fuel vapours from the tank? You can probably remove all that stuff and plug the connection to your intake manifold, don't want any vacuum leaks there.

[kalidasa]

I will check and report here.

I learnt from a colleague at work that it is a gas tank breather tube.
As gas is pumped out of the tank a vacuum is created and air is pulled into the tank through that tube.

Also, the line coming out of the intake-manifold is the for vapor or moisture release OR as you mentioned some sort of emissions thing where vapor is fed back into air-intake for efficient gas mileage.

The line from the gas tank goes into the black thing which has 4 holes (is this what is challed a charcoal canister?) and the line coming out of it has a different diameter compared to the air-intake line...

I shoved one into another and secured with gorilla tape...

[kalidasa]

I recall earlier this year someone referred me to check for a stuck exhaust valve or gasket. does this make sense?

[Firehawk989]

AFAIK most people get rid of the charcoal canister and block off the connection to the intake. You shouldn't have anything drawing vacuum on your tank, if it's a breather hose, you should just leave it open. (However, your tank shouldn't need a breather hose, since the gas cap is supposed to allow air in for that function.) The Chinese scoot that I used to own didn't have any emissions stuff though, so I'm kinda just speculating on some of this stuff based on how it usually works.

Do check your valve clearances, but I suspect with the dry spark plug that your carb is still clogged.

[kalidasa]

An update - i took the carburettor out and cleaned the main jet and the pilot jet. I discovered that the pilot jet was blocked. I tried using a sewing needles and it didnt work...took it to a motorcycle service shop and the tech helped clean it for me. Bring it back, assemble and a little starter fluid through the air intake did the trick! :yay:

One thing I noticed was the idle was great and adjusted the idle to nearly 2000RPM using the idle screw.

But, here is the thing - if I kept the throttle FULLY TURNED, the engine revs up to 6000RPM and revs down to 4000. Revs up and down and so on...what may be wrong?

Shall I try putting some fuel injector (lucas) and turn up the engine to a high idle? will this do the trick.

At this point, it starts and idles fantastic. woohoo :thanks:

I will let the breather be and undo my surgery (connecting the breather to the intake-manifold line). thanks.

[blueboy5000]

turn your mixture screw out 1/4 turn, for a slightly richer mixture. RPM surge is lean condition.

[Firehawk989]

An update - i took the carburettor out and cleaned the main jet and the pilot jet. I discovered that the pilot jet was blocked. I tried using a sewing needles and it didnt work...took it to a motorcycle service shop and the tech helped clean it for me. Bring it back, assemble and a little starter fluid through the air intake did the trick! :yay:

One thing I noticed was the idle was great and adjusted the idle to nearly 2000RPM using the idle screw.

But, here is the thing - if I kept the throttle FULLY TURNED, the engine revs up to 6000RPM and revs down to 4000. Revs up and down and so on...what may be wrong?

Shall I try putting some fuel injector (lucas) and turn up the engine to a high idle? will this do the trick.

At this point, it starts and idles fantastic. woohoo :thanks:

I will let the breather be and undo my surgery (connecting the breather to the intake-manifold line). thanks.

Nice! Yea, I suspect it has something to do with your hose surgery assuming it ran fine before. Almost there!

[kalidasa]

I still have a problem - even after turning OUT the mixture screw on the carburettor:

1. When the vehicle is on the stand and I turn the throttle full, the RPM goes to 6000-8000RPM.
2. However, when I sit and drive it around the parking lot, the max RPM is no more than 5000 RPM and it rises and falls. I have the throttle turned FULL and I get the semblance that it may pick up and go more than 15-20MPH (ie 5000RPM), it does not.

Any pointers, please?

[Firehawk989]

I still have a problem - even after turning OUT the mixture screw on the carburettor:

1. When the vehicle is on the stand and I turn the throttle full, the RPM goes to 6000-8000RPM.
2. However, when I sit and drive it around the parking lot, the max RPM is no more than 5000 RPM and it rises and falls. I have the throttle turned FULL and I get the semblance that it may pick up and go more than 15-20MPH (ie 5000RPM), it does not.

Any pointers, please?

Probably shouldn't have messed with your mixture screw. Turn it in all the way and then turn out around 1 and 1/4 turns for the stock setting. (I think!)

From there turn it small amounts one way or the other and test it each time. Eventually you will find where it runs best.