New Jonway 250YY won't start after 48 miles. By neally (Read 2,396 times)

[neally]

I bought a new 2009 JonwayYY bike late last month. It's very cool and super fun. It got parked for 2 weeks in my Texas garage after driving it only 48 miles. When I to went to ride it after 2 weeks, it ran, then sputtered for a few seconds then died. After that it refuses to start at all. Drained the battery several times.

Fuel pump works. It kicks well and runs with starter fluid sprayed into cylinder.

Frustrated. I even installed a new carb! It kicked and ran for 30 - 40 seconds then died again - and will not start again.

I am starting to suspect the automatic choke my be stuck or not getting a signal. Any help? The dealer I ordered it from is almost no help. I would return it, but he is too far.

[Cruiser]

Welcome to Scooter Doc, neally. The symptoms sound very much like tight valves. However, the easiest way to adjust the valves is with the engine running.

How did you determine that the fuel pump was OK? Did you actually see gas coming out of the fuel line when disconnected at the carburetor while cranking the engine with the starter? If it starts with starting fluid, then it sounds like a fuel delivery or automatic choke problem. By default the choke (enricher) is in the full choke position when it is cold and will remain that way even if it is broken or there is no power being supplied to it. If everything else is OK, the motor should start and keep running but eventually will show signs of a rich mixture. If the enricher is stuck in the extended position or the no choke position, then you will have trouble starting. This would be unusual with 2 different carburetors.

Since it starts with starting fluid, I would think you have fuel delivery problems especially since 2 different carbs will not work. The OEM fuel pumps are not the best in quality and you should have nothing but the best quality vacuum lines cut to the shortest length to optimize the vacuum pulses which is how these pumps work. Let us know how you determined that the fuel pump was OK. It could be just a leaking vacuum line for the fuel pump.

[damin69]

If You did not do the PDI I am thinking that would be a good place to start. I am thinking there may be a wire/connector issue and you are not getting spark. A good inspection off all the wire connections should be able to determine if that is the issue..

Good luck. and don't give up on it. Patients is the KEY...

[Alleyoop]

Welcome Neally,
Good to have you on the forum, do not worry there are many 250s guys on here that will get you riding into the Texas Sunset in no time. They just slabber all over the place when a problem comes there way to help solve the problem and they are very knowledgeable. As you can see we have an excellent Tech Section very well organizied on how-to many with real pictures.
Alleyoop

[mthomas]

Welcome Neally,
Here's what you do. Put some gas into a small spray bottle. Take off the back snorkel from the carb and spray two shots of gas into the back of the carb. Hit the starter and hopefully starts. If it starts to die, spray a bit more gas into the back of the carb. If you can keep it idling by spraying gas into the carb, it is a fuel delivery problem. If you could get it to start with starter fluid, you are getting spark. If I had to make a guess, I would say it is one of two things:
1. There was some junk in the fuel tank and it is getting sucked up into the carb and plugging the idle jet which allows the bike to start. There are two jets in the bottom of the carb that are brass and screw into the bottom under the float bowl. They have to both be clean and you should be able to see through both of them. They can be cleaned out with carb cleaner and a piece of small wire like guitar or piano wire.
2. Less likely is the plug is loose or fouled out. Check and see if it is loose and check the plug end making sure it is all the way on.

[neallyb]

I apologize for missing this helpful string when I needed it. How this tech request unfolded is as follows:
I determined the gas was indeed getting to carb by pulling off fuel line an cranking engine (like on my old VW's during college 200 years ago). I then ordered a new carb for about $44 and after priming it, it fired up great. It ran great, lots of power and serious cruising fun commenced. I put 1000 miles on it in a couple of months (now I'm really hooked). Unfortunately, in a couple of months, performance began to deteriorate, including lack of acceleration, frequently choking as I pulled back on the throttle to get out of intersections as quickly as possible. So instead of rebuilding the carb with the $29 rebuild kit, I bought another $44 one. Performance and power instantly returned. I do have the problem of embarrassing backfiring when I release the throttle - especially when braking from high speed - which I do frequently. I read elsewhere it's likely the jets running "lean" or "rich" depending on who you ask :-) Don;t know how to adjust the jets... thanks for the great support!!

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[neallyb]

On an interesting side note -- gas in central Texas is only available with ethanol additive - one of America's biggest rip offs. The tampered fuel is roughly 30% less efficient than "real fuel" and the increased evaporation leads to faster gumming of fuel line components. I've found real fuel still available near Waco and San Antonio... I may stock up to see it runs better and reduces down time. Thoughts?

[Bashan]

I've never heard of ethanol causing those kinds of running issues. Usually, backfiring when you release the throttle is from the air cut valve. Possibly you have a vac leak to the valve or it's faulty. Go to this link and you'll find an expert's thoughts on this problem. For some reason he lists it at #6 and then says it's the prime suspect. Here is a link to the manual for that engine. It should help with finding all of the lines involved. Rich