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Discussion Starter #1
This isnt a question about my Kat, but about my 1983 Yamaha 650 (900 kit), 29,000 miles..she'll start up just fine , like usual, but before after a few minutes of the choke, she'd run normal at a nice idle, never stall out...lately, actually over the last week, I've been noticing that as long as the choke is on, she's fine, but the RPM's wont increase after it's warmed up like normal, but still runs..then when you turn off the choke..within 10 seconds or so, she shuts off..I can start it right back up, and if I choke it, it's fine, but take it off, and same thing happens...I just changed the oil/filter last weekend, and fresh gas. Not leaking any fluids. When it's warmed up, you can start to smell it run very very hot..very quickly (alot quicker than usual, like with in a couple minutes) ... but there is nothing abnormal coming out of the exhaust and it doesnt smell like oil that I can tell.

any ideas?

Matt
 

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I'm going to guess it has been sitting a while since the last time you rode it and you are due for a carb clean.

Larry
 

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larryg said:
I'm going to guess it has been sitting a while since the last time you rode it and you are due for a carb clean.

Larry

Are you talking about tearing it apart or getting a can of Carb-Clean?
 

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Discussion Starter #4
Well..it sat for about 2 weeks since the last time I rode it, before I got my 2000 Kat last week..so all in all..it was about 2 1/2 weeks without running it...she started right up initially after changing the oil/filter/cleaning plugs, but then it started acting up.

If its getting a can of carb clean, i'll do that on monday..if its taking the whole sha-bang apart, then that might take awhile. let me know..thanks man. :thumbs:
 

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The only way to clean carbs is to take them completely apart and make sure all of the passages are clean.

That said, 2 1/2 weeks should not be enough to gum up the carbs but you could have some kind of contamination (dirt) blocking passages in the carbs. Other things I would look at before ripping into the carbs are...make sure the tank and float bowls are properly vented, drain the float bowls into a clear container to see if you have water contamination, check for air leaks, and inspect the air filter.

Larry
 

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Discussion Starter #6
Good points..I'll check it out tomorrow..been a long day today..UGH!! Thanks for the advice man..I appreciate it.
 

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Need4Speed750 said:
Good points..I'll check it out tomorrow..been a long day today..UGH!! Thanks for the advice man..I appreciate it.

How did you make out on it. Did you get it to run normal now?
 

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Discussion Starter #8
oh, from the info i got here in this thread, and also checking w/ a local dealer..they think its most likely the air filter..which is logical. I havent checked it yet, simply because I've just spent too much time riding lately..lol..but my father in law is taking his msf course in october and wants to practice so I better get to work on it this coming weekend..
I'll post up a reply when its finished.
 

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Air filter? I don't think so. If the air cleaner is clogged, shouldn't the bike run richer? Sounds like it's running lean. The carb is suspect, probably the idle jets. They are like the diameter of a human hair. One or all may be clogged.

Take the carbs off, and take off the float covers. Take out and clean the idle jets and main jets. Spray carb cleaner through them and all the other passages in the throat. Take off the floats (don't mix the parts) and check the inlet needles for wear. If your carbs are CV, check how the piston goes up and down. You may have to take off the vacuum chamber cover and clean each piston so it moves smoothly. Use vaseline to hold the diaphram in the groove (it sounds weird, but if yours has it you will know what I mean). Adjust the floats to specs, tighten the screws and install.
 
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