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-   -   Start-up Problem (http://www.gz250bike.com/forum/showthread.php?t=4713)

bjrscj 09-25-2011 08:23 PM

Start-up Problem
 
UPDATE:

So I checked the hose, and fuel came out just fine. So that's ruled out.

I didn't have all the tools to get the spark plug out, but I was able to start the bike. I pressed the starter while turning the throttle, and it managed to start. The problem is it would start to die as soon as I let off the throttle. Correct me if I'm wrong, but doesn't a spark plug become unnecessary once the chain reaction is started? I am under the impression that the explosions in the engine and the heat generated there mean the spark plug is only used to start the bike up. If that's correct, it seems like the carburetor is the next logical step in the chain.

If it is the carb, do you think getting gasoline additive would work if I can get the fuel to pump through again as I was able to tonight? Or do you think it would just be a waste of money and I should manually take it apart? Thanks again for all your insight.


ORIGINAL:

I've got a 2003 and it's been running great. However, after the weekend, I went to start up the bike, and it won't start. It turns very strongly, but it won't catch. It's sounds like the engines fine but the gas won't ignite and give that nice low rumble (well, low compared to just turning). Is this a starter issue? My only guess is that it rained for a few days and I didn't have a chance to cover my bike. Could that even affect it at all? That's the only thing out of the ordinary that happened recently. Thanks for your help!

Gz Rider 09-25-2011 10:37 PM

Re: Start-up Problem
 
...

alantf 09-26-2011 04:12 AM

Re: Start-up Problem
 
Quote:

Originally Posted by Gz Rider

First, check the vacuum hose. It's a 1/8 inch(axp) hose that goes from the carb to the fuel petcock. It gets old cracks and falls off. If it's cracked or off it stops fuel flow instantly.

One way to check the vacuum hose is to try starting in "prime". If the bike runs o.k. it's definitely a vacuum hose problem, as prime doesn't need a vacuum for fuel to flow. :2tup:

BTW, let it stand, in prime, for 3 or 4 seconds before trying to start, to give it time to fill the carb.

bjrscj 09-26-2011 07:12 AM

Re: Start-up Problem
 
I tried starting on reserve, and nothing happened. I also tried starting with the choke, and nothing happened. I assume that's what you meant when you said starting with "prime," but if it's not, please let me know. Every few tries I heard a low rumble, as if some gas ignited, but then it died out. I'm assuming there is a clog, like you said. I suppose I'll have to take it into the shop - unless you have any tips for fixing the problem myself.

Thanks for all your advice. I appreciate it.

music man 09-26-2011 07:26 AM

Re: Start-up Problem
 
Quote:

Originally Posted by bjrscj
I tried starting on reserve, and nothing happened. I also tried starting with the choke, and nothing happened. I assume that's what you meant when you said starting with "prime," but if it's not, please let me know. Every few tries I heard a low rumble, as if some gas ignited, but then it died out. I'm assuming there is a clog, like you said. I suppose I'll have to take it into the shop - unless you have any tips for fixing the problem myself.

Thanks for all your advice. I appreciate it.


Nope "prime" is a whole other setting, there are three settings on the petcock. On, Res and Pri. The Pri is for prime obviously, set it on that one and crank it over for several seconds and see what happens.

Gz Rider 09-26-2011 07:50 AM

Re: Start-up Problem
 
...

bjrscj 09-26-2011 08:07 AM

Re: Start-up Problem
 
Yah, I was actually just looking at the manual now. I appreciate that advice. It's a great resource. I am very new to the motorcycle world, and I do not have much mechanical experience at all. That being said, I'd like to learn, and I don't have much choice due to finances anyway. So the service manual is a great resource (although the pictures aren't that clear).

I'm going to check the prime idea and sparkplugs when I get home today. But I guess I've got one last question. If it runs on prime, the hose is obviously the issue, since the carb would be functioning. But if priming doesn't work, it could very well be the hose, but it could also still be the carb. Can I pretty much guarantee it's the carb if I don't see any cracking on the hose, or is there any way to tell 100% for sure that the hose is good before I take apart the carb?

Thanks again for all your help. It's a very overwhelming thing to me, and I appreciate your patience and insight.

blaine 09-26-2011 08:35 AM

Re: Start-up Problem
 
You can disconnect the fuel hose at the carb & turn the petcock to "pri" to see if you got flow down to the carb.If you have no flow,you have a issue with the hose or the petcock.
:cool: :)

mrlmd1 09-26-2011 11:19 AM

Re: Start-up Problem
 
Are you using the choke properly? Even in hot weather you may need some choke to first start up the bike in the morning after it sits for a while.

bjrscj 09-26-2011 12:25 PM

Re: Start-up Problem
 
I always use the choke. Even in hot weather I find that the bike doesn't really stay started without it if it's been sitting for a few hours.


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