250cc wont start or stay running By gpz550 (Read 3,850 times)

[gpz550]

Hi,

Im new to the forum and scooters in general. i have a good bit of mechanical knowledge ranging from cars to to small engines and motorcycles.
my son in law bought a 2008 jmstar (jonway) 250 cc. after research i learned that the engine seems to be the honda helix 244cc clone.
my current problem is that it will not start without starting fluid or stay running. when it does, it is extremely weak and dies soon. i have cleaned the tank and fuel lines out. removed and thoroughly cleaned out the carb as well as replacing the plug with a new properly gaped ngk plug. still having the same probelms. i have been having a hard time finding specs on this and am seeing a lot of the same things suggested that ive tried. i was looking at the valves as a possible problem but the adjustments are on the outside and from what ive read, it should be running and at running temp to adjust these. i have airflow, fuel is coming out of the carb and there is good spark. i have also checked to see if there was any air coming from the exhaust and there is. im getting stumped and not sure what im doing wrong at this point. i made a 1971 honda scrambler 350 run in about a 4 week span of time after it sat in a garage for 10 years.
thank you
Lee
my ride 1981 kawasaki KZ550 83 GPZ550 engine)

Read more: itistheride.boards.net/user/2387/recent#ixzz3CfCNkJir

[Bashan]

Use the Honda Helix manual for the engine. But it only applies to the engine, the rest of the manual is for the Helix aka Fashion. So you say you have spark and fuel? Yeah, probably valves. Here's a video from Mike at BPNW, he specializes in the 244 engine:

Try that and get back to us. Rich

[Alleyoop]

The problem for him is that the motor will not stay running to give him a chance to adjust the valves.

But if you can take a picture of where the valve adjusters are currently at we can get them close so that they are not to loose.
Alleyoop

[gpz550]

thanks. ill get a pic uploaded asap. thanks for moving me to the right place as well.

[Alleyoop]

It could also be the fuel ratio mixture, do you know where that screw is on the carb? You probably have a 30mm carb on it and the mixture screw may be UNDER the carb by the INTAKE MANIFOLD side which is a PITA to get at, and some it will be on the Left side opposite the Throttle cable side. If you can get at it first turn it clockwise to close it then open it up counter clockwise 2 1/2 turns which is a good starting point and if all is good it should run pretty good at that setting. You can always find tune it after the it is running if you find it is not running as good as it should.
Alleyoop

[gpz550]

this is where the valves are now. thanks for the post regarding the carb and mixture screw, that was my next question. and yes thats the exact carb it has

[gpz550]

[cyborg]

I would check the intake manifold and all connections (nuts and bolts) as long as you're in there already just to make sure everything is snug,,, I would also check the manifold and gaskets as well for cracks

[Alleyoop]

Sept 7, 2014 17:07:22 GMT -6 gpz550 said:

Well they look pretty good they should both be near the center and they are so I do not believe its your valves,
has to be the carb and fuel delivery or you have some air leak. So if you can adjust the carb, first close it clockwise until it stops then turn it out 2 1/2 turns and see if it acts better.
Alleyoop

[Alleyoop]

If it needs starter fluid to start it could be the enricher is not working. You can take it off and look at it. Here is what it should look like COLD (retracted) so it feeds extra fuel for cold starts.

If it is extended then it is bad and needs to be replaced.
Alleyoop

WHEN TAKEN OUT COLD IT SHOULD LOOK LIKE THIS(RETRACTED):


IF IT LOOKS LIKE THIS EXTENDED then IT IS NO GOOD REPLACE:

[gpz550]

thanks for all the info guys, ill have time to work on it this weekend and ill let you know how it goes.
Lee

[kz1000st]

This isn't a gravity feed system so I would check the fuel pump. Disconnect the incoming fuel line and see if it squirts when you spin the starter. If it does you still have a clog in the carb. If not then the pump is your problem. You could hook up a hose and funnel into the carb and see if it runs that way. It might then be either a bad fuel pump or a vacuum line is off somewhere and preventing the pump from getting adequate suction to operate.