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Post by dakotafig on Aug 12, 2014 13:06:49 GMT -5
Ok, I had went ahead and ordered a new one. It checked its gap and it is 0.025", a little tighter than the 0.027" the old one was. Below is a side by side picture of those. I hope I'm being taken in the correct context by everyone, I just want to understand everything, make sure I'm not missing anything, that would be the engineer in me.  I'm still trying to understand the spark plug color, and hopefully eventually the root of the occasional stutter at high throttle, and quick throttle deceleration. I'm going to go pick up a manual fuel shut off valve to test the theory of the fuel valve loosing enough vacuum to shut the fuel off. I will probably pick up some more main jets, but I don't know how far leaner to go based off the plug color. Thanks again everyone for your help.   |
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Post by JerryScript on Aug 14, 2014 0:03:23 GMT -5
Looks like the flash is making the tips hard if not impossible to see in some of those photos, but if it looks like the new one, you should be fine. The color on the older plug looks good in those pictures, nice coffee stained look to it.
I'm still wondering if it's a lack of vacuum at WOT preventing fuel from flowing periodically. Some people with the issue of stuttering at high speed use a manual petcock that you have to turn on when you start your scooter, and NOT FORGET to turn off when you get off your scooter. This is a free flow system when turned on, and must be paid attention to, as the float pin could be overwhelmed by the weight of the fuel.
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Post by dakotafig on Aug 14, 2014 0:30:29 GMT -5
JerryScript, I'm planning on picking up (or rigging) a valve to test ASAP. I was hoping to hear an educated thought on my plug color before I ran down to the motorcycle shop in case I should pick up a different jet.
As for the pictures, I could totally see the flash being an issue now that I look back at them. My iphone took a ride through the wash machine and the camera doesn't work anymore. So, I rely on a guy at work to take the pictures and his phone camera isn't quite the same. I knew what I was looking at so I just saw what I knew I was looking at in the photos.
If the fuel valve is to blame, does anyone make an electronic shutoff valve? I don't know if I would want to rely on my memory.
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Post by JerryScript on Aug 15, 2014 0:09:05 GMT -5
I don't know of any made specifically for a gy6, but any 12v electric fuel valve of approximately the same size should work. I found several possibilities with a simple google search, made for various equipment, but none I would personally recommend.
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Post by dakotafig on Aug 22, 2014 14:54:08 GMT -5
Ok, quick update. So, I put in a manual valve, and holy cow what difference that made. The thing went from running really pretty good to being rich as all get out. The high speed stutter still happened every once in a while, but it was drastically different then before. Not quite for sure how the fuel valve could make that much of a difference, but it appears like it was being more of a fuel regulator than a fuel valve. That also could explain why such a big jet was resulting in the scoot running really good, at least I guess.  At any rate, vacuum fuel valve in there, runs great, but at full throttle a stutter appears every now and then. With manual fuel valve, runs like crap, really really rich. Next step smaller jets and evaluate again. Anyone have any other thoughts? |
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Post by JerryScript on Aug 22, 2014 23:31:13 GMT -5
Right on! Good to know we are on the right track!
The reason the vacuum petcock fails at high speeds is due to a lack of vacuum from the carb. At WOT, you would think you would have the most vacuum, but in fact you have the least. Since the vacuum from the carb is what opens the vacuum fuel petcock, you end up with no flow when the vacuum gets weakest.
Remember when re-jetting, test a jet and if it's rich or lean, adjust the needle before trying a different jet.
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Post by dakotafig on Sept 24, 2014 15:33:41 GMT -5
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