yamaha GT80 won't start

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Feb 20, 2007
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#17
i have that same bike and had the same problem when you took the carb off and put it back on didi you make sire that the slot in the plastic ring in the carb (where it attaches to the motor) is lined up with the screw where you tighten the carb to the motor. this creates a vacum and instead of sucking gas from the carb it sucks air
 
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Mar 4, 2007
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#18
no, I had no idea that it was even there. I just kinda went back and forth with the carb andslid it onto the pipe from the motor. the plug as wet though, and smells like gas. but I will check that out for sure. oh and while I'm at it, how do you get the rubber boot from the carb to the air box back on? its drivin me crazy. and if I ever have to do a top end on it, I cant figure out how to get the exhaust pipe off...thanx!
 
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Oct 21, 2006
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#19
If the plug is wet its getting fuel probably too much and its flooded. You may still have a problem with the carb, or it could just be flooded, it happens. Turn off the fuel try a new plug or clean the old one, it should eventually clear out and start, you may have to clean the plug a few times before it starts.
 
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Nov 14, 2006
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#20
If you put the carb slide in backwards than it won't close completely and the bike won't start. Also check the timing, if your flywheel sheared it's key than your timing could be way off and it won't start. Using starting fluid could bend your rod.
 
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Mar 4, 2007
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#21
did try the starting fluid, but it didn't even sputter. I'll have to check the carb stuff out tommorrow. hope to get her runnin this weekend.
 
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Mar 4, 2007
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#22
ok, been a while, but found out I may have flooded it when I tried the restart. was told that if you use the choke and throttle, it could have sucked gas down into the crankcase causing it to gas foul the plug.

so guess I got to pull the plug, remove the tank, and turn the bike upside down...kick it over a few times while upside down.

turn back over put in new plug and try to start with carb cleaner only(no choke and no throttle) , if it starts it'll draw the gas in and then run as it should.

so, I guess I got something to do tommorrow...hope it works!
 
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Jan 25, 2007
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#23
or you could try my way you don't have to do all of that when i flooded my bike i just put a paper towell in the hole and kicked very hard for about 10mins and tried to start it without the gas plugged up witha new spark plug and any gas that was still in there would make the bike run and it will burn all the gas out if there is any in there, but this only works if the bike works.
 
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Mar 4, 2007
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#24
well, the bike didn't start. tried and tried and tried...wore me out. can't get anywhere with this little bike. put my finger over the plug hole and it didn't pop my finger off. but don't know how much compression is supposed to be in this little engine. anybody know?
 
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Oct 21, 2006
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#25
If it wont blow your finger off the plug hole it dosnt have enough compression to start. :(
 
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Jul 20, 2006
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#26
One last thing to try before tearing it apart is to get some to push you down the street and try bump starting it. That seems to help push out the gas down in the crankcase. Just a thought.
 
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#27
I think I'm in the same boat. New to this site. New to dirtbikes and 2 strokes. Bought it used. Ran it hard for about 2 hours and it died. compression measured at 80 psi, so I installed a new .5 mm oversized piston. compression at 120 psi.
It won't start! I tried the idea shared to crank it over upside down to drain the gas. I was able to get it to run, but only for a short time. I think previous owner stated he installed a larger jet in the carb. Could this be the problem?
What size jet should I be running?