Question about 2001 Honda Cb 400 Super Four

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Wont start After sucking on the vacuum tube, fuel spurts out of carb intake hose, tanks free from debree and carbs pour fuel from sediment bowl, good charge battery, ****** still wont start, was running fine three days ago, hasn,t moved an inch, the down tube from the petcock in which I believe is the vacuum tube goes down into the engine casing, to where???? and where is the vacuum created ?, tried putting an inline filter in to see if fuels getting through to the carbs, and yes its pointing the right way round and yep the fuel was straight there, started straight away and ran sweet as a nut, but now there's now't and I havn"t got a clue, please help x

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3 things are needed for combustion (compression, fuel/air mixture & spark). if fuel is making it to the carb and out the drain tube, then it might not be a fuel issue. i'd turn to spark and see if that fixes it. it has for me on dirt bikes and ATVs. one minute it was running, shut it down for a break and when trying to restart, nothing. changed out the spark plugs and viola'....she's alive again. never had luck with NGK plugs.

worth looking at the air filter too. make sure you can still see light through it when holding it up to a light. and you should feel/hear a suction while trying to start it which means the passage to the carbs are clear.

try this. petcock on try and start it. try for a few seconds (<10 sec) to give a start. stop cranking and immediately pull out the plugs. are they wet? if they are, then fuel is making it to the cylinder.

take a look at the plug. is it black (like its running too rich?) or is it very white like a new plug (lean condition)? should look like light brown toast if its running right. throw in a few new plugs and give it a try no matter how they look to see if this works.

Posted on Jan 15, 2009

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