help! rough idling and eventual stall - diagnosis?

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caleb

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hey folks,

so, i'm new. i mean, REALLY new. as in, just figured out where to put oil in.

i bought (private sale) a 1983 yamaha xj650 maxim on july 14th of this year (two weeks ago), and it was certified. almost immediately, the bike started stalling.

i'll start the bike, let it warm up for about five minutes (maybe less with the heat wave), and start riding. after about ten minutes, it'll start to chug or threaten to stall at red lights, so i put the choke on full to try and save myself from stalling. this'll work for another ten minutes or so, and then the bike gives up on me. sometimes it'll start up again right afterwards, sometimes not.

i know this type bike is known for carb problems, but those were apparently cleaned when it was certified.

any ideas what's going on? i'm hoping it's something easy (i.e. run some sea foam through it - haven't done this yet) rather than having to take it in.

any help is greatly appreciated.
 
caleb said:
hey folks,

so, i'm new. i mean, REALLY new. as in, just figured out where to put oil in.

i bought (private sale) a 1983 yamaha xj650 maxim on july 14th of this year (two weeks ago), and it was certified. almost immediately, the bike started stalling.

i'll start the bike, let it warm up for about five minutes (maybe less with the heat wave), and start riding. after about ten minutes, it'll start to chug or threaten to stall at red lights, so i put the choke on full to try and save myself from stalling. this'll work for another ten minutes or so, and then the bike gives up on me. sometimes it'll start up again right afterwards, sometimes not.

i know this type bike is known for carb problems, but those were apparently cleaned when it was certified.

any ideas what's going on? i'm hoping it's something easy (i.e. run some sea foam through it - haven't done this yet) rather than having to take it in.

any help is greatly appreciated.
Click to expand...

welcome, you might want to post this in the technical section. Lots of experience there that could help you out
 
What colour is the smoke? is it heavier/darker?

My money's on too rich or bad plugs.
 
dkolbasovsky said:
check your plugs. Might be a carb adjustment with the hot weather.
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i think you're right about the carb adjustment - and considering that the carbs had just been cleaned prior to me buying the bike, i'm thinking maybe they just weren't put back together correctly.

spark plugs are new, though.
 
Take the fuel filter off and see if you can blow through it. If your cheeks puff out or you feel "any" resistance, it's plugged with the sediment of your stale gas. Change the fuel filter. New gas. Google your bike and add "fuel filter" to the search for the fuel filter location on your bike.
 
Prince said:
Take the fuel filter off and see if you can blow through it. If your cheeks puff out or you feel "any" resistance, it's plugged with the sediment of your stale gas. Change the fuel filter. New gas. Google your bike and add "fuel filter" to the search for the fuel filter location on your bike.
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thank you! i'll try this tomorrow and get back to the thread with the results.
 
Sometimes after a cleaning, debris becomes dislodged and can later land in spot that plugs or restricts.

When it stalls out, open fuel tank cover and listen for a hiss sound (as air rushes in) in case it is a faulty vent.

Also confirm if this happens with a near full tank of gas.

And also look for cracked/or pinched vac lines coming from fuel petcock (which operate on vacuum from engine and if cracked is sorta like having the valve turned off).
 
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caleb said:
there is no smoke colour, as far as i can see. and the spark plugs are new.
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Next q for me...were the plugs gapped properly? Wires firmly installed?

Also major one....was the bike running like that before the plugs were changed?
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