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Wish I were a Leesta too
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Discussion Starter #1 (Edited)
need carb help with '95 EX500 please...update: fixed

my left carb started dumping a ton of fuel into the cylinder on the way home yesterday. here's what happened. about 5 miles into the ride at a stoplight, the idle drops about 400 rpm and the idle gets rough. i smell gas. i rev it a bit, nothing changes. i take off with much less power until about 4k rpm then everything seems normal and the bike rides fine. get to the next stop sign and everything seems fine until about 10-15 seconds after i stop then the idle drops again, and i smell gas again. this repeats all the way home. its fine if its revving, fine until the throttle is closed, then the idle goes to heck, i smell gas and the exhaust wreaks of raw gas on the left side.

so i took the carbs off, removed the plugs and checked that the pilot screws was 1 3/4 turns out. they were. when i took the carbs off, there was gas in the front (slide side) of the carb in a little puddle. took the float bowls off and checked the operation of the float needle valve because i thought it wasn't closing all the way and the float bowl was flooding, (which still seems like the likely cause) but they seemed to operate freely and correctly, floats appear to be fine with no leaks and set to the correct level. there were no other visible signs of wear or problems. i just synched the carbs but this didn't start until about 50 miles later. it ran great until this rich condition presented itself.

so what's my next step? its just dumping a ton of gas into the cylinder which is just blowing out the tailpipe unburned and running horribly. i still think that the float bowl is flooding. perhaps i should disassemble the needle valve and clean it? HELP! i need my bike! thanks all!

Bobby
 

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second chimp in space
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The needle valve would be a good thing to check while the carbs are apart. Also check that the orings in there are all in one piece. There is one around the needle valve and another one for the choke. Look at ronayers' microfisce to find all the orings for your carbs.

Another option might be that for some reason the petcock is letting gas in the vacuum line. Though this doesn't seem very likely, since that would mean a hole in the diaphragm and that would mean that the petcock wouldn't open enough to run the bike at higher revs.
 

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Sounds like the float was sticking.
 

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Wish I were a Leesta too
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Discussion Starter #4
thanks for the reply. i checked the petcock and it operates fine. i also checked, but didn't full disassemble the choke mechanism. it seems fine. the diaphrams hold up to a vacuum test so i don't think thats it. i think i'm going to have to fully disassemble the needle valves and check for debris. its soundsing more and more like the culprit. thanks again! any more suggestions are more than welcome. thanks all.

Bobby
 

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Take them completely apart. Sounds like you have debris somewhere in them. Had the same thing happen. Piece of debris was next to the float needle keeping it open.
 

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This is almost certainly what the problem is.
 

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Bobby, I have both factory service manuals for the '94+ EX500. Drop me a line if you need to borrow them, I live in W. WA too (Bonney Lake)


Craig
 

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Wish I were a Leesta too
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Discussion Starter #8
wow! thanks for the offer Craig! i just might have to take you up on that. i've got the Clymer manual which has a pretty detailed account of how to disassemble the carbs. if i can't get it from that i'll drop you a line and take you up on that offer. i'm in Puyallup so i'm just a short trip up 410 away from you. i'm going to tinker with it tonight and sunday and hopefully get it straightened out. i have to fix an overheating car first though. since bad things always come in threes and my car and my bike are both on the fritz, i'm just waiting to break a toe or something. (knock on wood) thanks again.

Bobby
 

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No problem, I don't ride the EX too much anymore and just tuned it up so the manualls are just sitting. Let me know if you're up for a ride, im out all the time.

Craig
 

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Wish I were a Leesta too
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Discussion Starter #10
will do. i see you also have my next bike. after i'm done with the EX, i'm all over that FZ6. i just love that thing. maybe next summer. seems a natural progression. how do you like yours?

Bobby
 

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Well, bought a brand new '05 FZ at the end of Jan and now have 7000 miles on it :) The only thing I don't like is the seat, Im gona have a gel pad put in one of these days. Why am I not on it now?????

Craig
 

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Wish I were a Leesta too
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Discussion Starter #12
it was a small piece of plastic shaving from when i drilled a hole in the bottom of my water bottle/aux fuel tank. i wans't careful enough in keeping debris out and it got stuck in the right carb causing the needle valve to not close all the way. it presented as the left carb bacause the crossover tube between the floats evens out the fuel in each bowl and the bike was on the centerstand but slightly leaning left causing more fuel to flow into the left carb float bowl. turns out both of them were running crumby. but its all fixed now. thank goodness. now if i would have just remembered to change the plugs while i was in there so i didn't have to take the tank off again, that would have been great. oh well. thanks for the help all!

Bobby

Craig, thanks again for the offer. someday i'll have to get a hold of you so i can drool over your FZ6.
 

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Good to hear you got it all taken care of and that it was something fairly easy. You missed some great riding off of hwy 101 on Sunday :D



Craig
 

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If it was dumping a lot of gas change your oil and filter asap.
 

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Wish I were a Leesta too
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Discussion Starter #15
sorry i missed it Craig. it sure was nice out. i did get to go to the airshow at McChord AFB though. i'm a pilot too so that was plenty fun for me. i did just change the oil and filter before all this happened, but it didn't run long enough in this condition to cause worry. i thought about that too but the oil has no gas smell and is still brand new looking. thanks!

Bobby
 
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