2008 Rocketa MC-54 250B will crank but wont fire? By 860johnjohn (Read 1,108 times)

[860johnjohn]

Hello,i just purchased a used rocketa 250cc.It has full charge battery and when i turn key lights come on in dash and horn works.When the kill switch is on she cranks but doesnt fire.When the kill switch is off she doesnt do nothing at all.Please help
John

[Alleyoop]

Did you not start it up and run it before buying it? If it was running when you bought it WHAT has changed since you brought it home?
When you say KILL SWITCH IS ON SHE CRANKS, is this mean the killswitch is on the RUN POSITION or NO RUN POSITION?

Take the Spark Plug out or if you have a SPARE Plug just takje the boot cap off the plug in the motor and stick the spare plug in the boot and hold it on the VALVE COVER or on the motor someplace and crank it over and see if you have spark.
Alleyoop

[860johnjohn]

Will do this asap,thanks

[860johnjohn]

Mar 11, 2016 14:22:42 GMT -6 Alleyoop said:

Did you not start it up and run it before buying it? If it was running when you bought it WHAT has changed since you brought it home?
When you say KILL SWITCH IS ON SHE CRANKS, is this mean the killswitch is on the RUN POSITION or NO RUN POSITION?

Take the Spark Plug out or if you have a SPARE Plug just takje the boot cap off the plug in the motor and stick the spare plug in the boot and hold it on the VALVE COVER or on the motor someplace and crank it over and see if you have spark.
Alleyoop

[860johnjohn]

Ok,the scooter turns on but after about 30 seconds it turns off.Would you happen to have a link where i can see a diagram of how the carburetor is set up.I think theres hoses going where there not suppose to.Also which motor oil do these things use?Thanks ahead of time.

[bobf]

Which 250cc engine do you have? The vertical Honda or horizontal Linhai style?

Can be very confusing but many tubing setups shown. Can you find your carb set up in these many photo's?

images.search.yahoo.com/yhs/search;_ylt=A86.JyZQieVWlHwAjHMnnIlQ;_ylu=X3oDMTEyaDZwMzVuBGNvbG8DZ3ExBHBvcwMxBHZ0aWQDQjE3MjBfMQRzZWMDc2M-?p=Honda+250cc+Chinese+Scooter+Engine+Carburetor+Hose+Diagram&fr=yhs-mozilla-003&hspart=mozilla&hsimp=yhs-003

[Alleyoop]

Best is to take pictures of your carb area and I can tell you if something is in the wrong place.

Here is a picture of a 250 the carbs are all the same and the vacuum hoses to the carb are the same for any of the 250s.
Alleyoop

[860johnjohn]

Mar 13, 2016 9:43:59 GMT -6 bobf said:

Which 250cc engine do you have? The vertical Honda or horizontal Linhai style?

Can be very confusing but many tubing setups shown. Can you find your carb set up in these many photo's?

images.search.yahoo.com/yhs/search;_ylt=A86.JyZQieVWlHwAjHMnnIlQ;_ylu=X3oDMTEyaDZwMzVuBGNvbG8DZ3ExBHBvcwMxBHZ0aWQDQjE3MjBfMQRzZWMDc2M-?p=Honda+250cc+Chinese+Scooter+Engine+Carburetor+Hose+Diagram&fr=yhs-mozilla-003&hspart=mozilla&hsimp=yhs-003

Thanks, Do you think it could be loose or tight valves?

[860johnjohn]

Mar 13, 2016 12:28:09 GMT -6 Alleyoop said:

Best is to take pictures of your carb area and I can tell you if something is in the wrong place.

Here is a picture of a 250 the carbs are all the same and the vacuum hoses to the carb are the same for any of the 250s.
Alleyoop

Thanks i will take pics soon

[Alleyoop]

Motor oil any 10w40 oil the important thing about the oil is change is every 1000 or so miles.

[bobf]

I will just advise to let Alleyoop help you as he has helped me a lot.

It would be helpful to tell us if horizontal Honda engine or vertical Linhai engine. As Alleyoop has advised the same carb is used on both but after that much can be different. Examples might be the covers will have some differences and especially under the seat items. Doing the valves on a Honda is much easier and more direct to get too than the Linhai.

The actual horse power of the Honda is less than the Linhai. The 250cc is a generic number used by a range of actual outputs.

My scoot is the Honda and I have been working with it for quite a while now. Had some real problems like boiling over so had to replace the thermostat and fan controller. Then had problems similar to what you are claiming. I changed the carbs but no advantage and went back to the original carb. Many problems I have had were due to the air system to the engine. It must be good from the intake box all the way to the carb. Nice fitting connectors with no extraneous air leaks. I did replace the air tube from the air intake box to the carb. Be sure they fittings are completely fitted and the clamps tightened well. I put a new fitting on the back of the carb to the engine intake port also.

As soon as I get my scoot running I will take a few rides around town to make sure, then it will go on sale. I am now climbing the hill towards 83 and my better half is wanting me to let go before I do something dumb, as older folks do things.

Fix and learn and then ride.

[860johnjohn]

Tried my best withs pics,it was kind of uncomfortable with plastics still on.thanks

[Alleyoop]

Ok, I see "ONE" problem right away why it will not stay running.

See that BRASS connector on that SAUCER looking piece, that needs a VACUUM hose attached to it.

LOOK at this picture CLICK ON IT TO SEE IT BETTER: SEE how the VACUUM HOSE from the INTAKE MANIFOLD goes into a "Y" and one end goes to the SAUCER(Which is your ACV VALVE) the other goes to the FUEL PUMP, NOW if you have a hose going to a CANISTER then you need another CONNECTOR to also get VACUUM to it.

HERE I DREW HOW YOU SHOULD HAVE THE VACUUM HOSES CONNECTED:
CLICK ON THE PICTURE TO EXPAND IT:

[860johnjohn]

Mar 14, 2016 11:47:34 GMT -6 Alleyoop said:

Ok, I see "ONE" problem right away why it will not stay running.

See that BRASS connector on that SAUCER looking piece, that needs a VACUUM hose attached to it.

LOOK at this picture CLICK ON IT TO SEE IT BETTER: SEE how the VACUUM HOSE from the INTAKE MANIFOLD goes into a "Y" and one end goes to the SAUCER(Which is your ACV VALVE) the other goes to the FUEL PUMP, NOW if you have a hose going to a CANISTER then you need another CONNECTOR to also get VACUUM to it.

HERE I DREW HOW YOU SHOULD HAVE THE VACUUM HOSES CONNECTED:
CLICK ON THE PICTURE TO EXPAND IT:

Will try this tomorrrow!Thank you for taking time to help me out

[Alleyoop]

Not a problem the Vacuum hoses are connected wrong is all.
Alleyoop