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Why am i not getting gas to the pistin?

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I was riding my 1981 xl185s one day after replacing a timing chain and probably 20 minutes into the ride... it came to a halt as it slowly died. After towing it back to my shop i try adjusting valve clearance and completely cleaning out my carb and checking timing and everything was spot on except the clearance had to be adjusted to be made perfect. Still wont start. I then remove the plug after kicking for a long while and find it dry. So i then go to my handy dandy can of Carb cleaner and spray some directly into the combustion chamber above the piston and then replace my plug and BAM! Started right up and ran until i killed it after a few seconds. Also, at one point i did check the float and it was in fact full of gas. So my question is, Could the timing still be off since i simply sprayed above the piston? What do you guys think could have happened? Any feedback would be GREAT! i'm all out of ideas.

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After cleaning the jets and passages I would also recommend putting an inline fuel filter in place. Also check that the fuel cap vent is venting properly and not rusted closed.

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Ill go back and take the carb apart farther and clean it all out again today but the vent cap is a good idea. That cap is the original from from 1981 so its bound to have some rust up underneath. but do any of you guys know if my timing has to necessarily be even close to right for it to run even if i just spray cleaner above the piston? Just trying to eliminate possibilities. Thanks!

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I was thinking the cam timing might be 180 out, but wouldn't explain why it ran off the cleaner. Wouldn't hurt to check I guess. Just feel for suction at the plug hole and check the grounded spark plug sparks during the next upstroke. Might be a better way, but that's what I'd try.

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I was thinking the cam timing might be 180 out, but wouldn't explain why it ran off the cleaner. Wouldn't hurt to check I guess. Just feel for suction at the plug hole and check the grounded spark plug sparks during the next upstroke. Might be a better way, but that's what I'd try.

it definitely feels and sounds like everything is lined up with plenty of spark, but I took off the carb and the plug and then shined a flashlight through the plug hole and confirmed that the valve is opening as it sould and that there is no blockage. im really starting to think that its the carb not getting gas through.

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Maybe the idle jet is blocked. Maybe you can get a strand off a stranded copper wire and try to gently push it through. might need to soak it in one of those cans of carby cleaner. I just go a half hour or a little less than directed, so the holes in the jets don't get too big because it does eat metal eventually. Then rinse as directed, then blast all the holes and jet with carb spray. When you spray into the idle jet, you should see some coming out into the hole in the carb, but it might not spray out, because it may be a very crooked path it follows. Watch your eyes. Hmmm, that's hard to do, I mean be careful not to get spray into them.

While you're at it, if you haven't already, you might want to flush the gas tank. I just put a little gas in, shake it up, dump it out, repeat a few times.

Edited by knudsen

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