WHAT COULD BE WRONG? A puzzling problem By thomasg (Read 689 times)

[thomasg]

Hi Folks:
I know that this part of forum belong to big guys with 250cc, I was not able to locate a better place so I do apologize for posting it in here. I am not trying to break any rules!
Now! This is about an old problem that I am still trying to resolve and has puzzled me for a long time. A vintage 1983 brand new 80cc Honda Aero that I bought in state sale last fall. The scoter has only 75 miles and was stored with very little next to empty gas. Otherwise it is still in a new condition
SYMPTOMS: The issue is that the scooter loses power and shuts off after running for only 200 yards, feels like it is not getting gas. When the scooter shuts off it is very hard to start it right back up like it is all out of gas, But after sitting for a while it starts right back up. It cold starts just fine and idles perfect. The 1st take off is strong as strong as it can easily carry me 300lb and my 7 years old son easily. But again it shuts off right after 150 to 200 yard driving. Please note while idling there is not any problem the problem starts after driving the bike. And again it feels like it is not getting enough supply of gas…
THINGS DONE SO FAR: Because the scooter was stored for such a long time I start to do inspection and cleaning, only thing that I didn’t pass my primarily inspection was that the rubber O-ring inside the petcock had melted and almost 85% main orifice looked to be clogged to prevent gas entry (on the pic.1 you can still see a trace of the rubber). Then I have cleaned the carb. and all jets very carefully and meticulously both with solvent and air. in addition changed all the vacuum hose and fuel hose and a brand new battery. These issues where address in accordance to the manual and SCOOTDOC forum based on my previous post regarding this matter:
Petcock---Checked---tested for vacuum---works---using the old one
Air filter---Brand new installed
Carb---Cleaned---all jets open and clean
Carb-float---adjusted---float level tested ok
Air mix adjustment---Factory preset
Fuel mix adjustment---adjusted
CDI-unit---changed---new one installed (preventive)
Reed valve---UNCHECK
Conclusively
After everything I done above and still having problem could be that I have still bad petcock? Why because that is the ONLY part that I didn’t change that has to do with fuel delivery. What about the Reed valve? It looks like a new valve especially for a scoter with such a low mileage.
This has become a big puzzle for me … Your advice is highly appreciated …

Attachments:

[madcollie]

thomasg,

I didn't see anything mentioned about the fuel line and/or filter. It sure sounds to me like it isn't getting fuel. Are you sure there are no vacuum leaks?

"The issue is that the scooter loses power and shuts off after running for only 200 yards, feels like it is not getting gas."

Got enough gas to get rolling but not enough flow to keep it going. Let it set for a while and gas slowly gets down to carb.

Have you pulled the gas line to see if the fuel streams out when you try to crank it?

M/C

[Alleyoop]

You can test the Petcock to see if gas Dribbles out or streams out. Disconnect the fuel line by the carb and Vacuum hose, then suck on the Vacuum hose Fuel should Come pouring out. If it dribbles out get a New Petcock.
Alleyoop

[tvnacman]

I had a honda with a 70cc that sat for a while it didn not have the vac fuel valve , what I did find was the inside of the gas tank was rusted pretty bad and the fuel lines would get clogged real bad , I had to change the fuel line every two weeks .

drain the tank and see if it is rusted inside , if it is (i'm sure ) you will have to get the tank out of the bike and dry it out, put then get a hand full of nuts put them inside and shake it all around (to loosen up the rust flackes) clean it all out . Then they sell a two step solution first etch the tank inside then the second step put the other solution and coat the inside of the tank then dump and wait .
I know when I bought it , it came from JPcycles.

John

[sprocket]

>>are not made of hi grade plastics

They are... the laws require metal in most places (fire prevention) so they go with that. Pretty easy to swap them for a poly tank if you don't get inspected annually.

I have seen some new gas tanks that have a poly liner on the inside which is blow-molded into the metal tank. Best of both worlds

[thomasg]

Thank you for the tips, even after I thought I said everything I still left out some points. For the spark-plugs yes I did change it to the Irridium NKG to have it on the best quality possible. the fuel line and the vacuum line are brand new so is the fuel filter even put all new clips (clamps)!
As far as the vacuum test on the original petcock goes I did vacuum test it and I actually noticed a flow and not a drip however I am not sure if the amount of flow is sufficient enough because I had nothing to compare it with. Again the scooter idles perfect and has a great pickup (surprisingly great!!!) but it cuts short like it is not getting gas after short distance driving ONLY!. So even if we go by elmination process. I beleive the petcock is culipit or?
this is really left me in BLUE please keep you suggestion coming and ---->THANK YOU

[tvnacman]

so change the petcock its a twenty dollar bill !!!!

[sprocket]

Does the flow look like pee? It is adequate then...

How did you test the petcock? Perhaps the vacuum on the intake elbow is poor? The vacuum hose has a leak etc. Replace those metal spring clips with 4" zip ties and pull them tight with pliers... you will never have a vacuum leak problem again...