Houston we have a problem.  The bike idles fine and runs great up to about 130 - 140k, then it surges like it's running out of fuel.  If you never take it past 120, it'll run all day long without the slightest hesitation, however if you take it up to 140 and then back down to even 110 it surges from then on.  When we first brought it home we got 10 miles down the highway and the little sucker stalled and wouldn't start without the choke.  After some investigating we discovered a kinked tank vent line so that solved that but she still has this surging problem.  We took the tank off and cleaned it, cleaned the lines, made sure there was fuel running out the bottom of the carbs, cleaned the petcock,  ran a couple of tanks of carb cleaner through it and still it surges on the top end.  Before we bought it design cycle set the valves, synced the carbs, and did a tune up so I don't know what to think. :dunno:  Oh by the way, this is a 92 cbr 600 with 24000k and it has no fuel pump.  Anybody have any ideas?????

i would rebuild the carbs.  it definetley sounds like a fuel problem to me.  probabley have some gunk and crap built up in there. it happens.

whenever ive had a problem with a surge it was the fuel air mixture. on my tracker it was the maf sensor, on my bike the main jet was too big and the extra gas/oil flooded the motor and sometimes fouled the plugs and they wouldnt spark consistently. at full throttle it would clear up but when you let off it would bog then clear and bog again, etc.as john said i would start at the carbs then move to ignition as a weak spark can do some wierd shit too. actually the first thing i would do is ask jamesgoodchild. he seems like he has a few years of knowledge.

I agree with the previous comments sounds like air/fuel mix is wrong.  There's only four things that could effect it.  Problem with gas supply, problem with air supply, problem mixing them (carb) or problem burning them (ignition circuit).  Check the carbs to make sure they move freely, no sticking points including cables binding. You may even want to lube the cables to make sure they release smoothly.  Ahlso, check the air filter as well.  Make sure you have no blockages there.  For a real quick test, pull the air filter and do a run to 130-140K and then back down to 110 and see if it still surges.  If that doesn't fix it, then it sounds like its time to go to the next easiest check, tearing the carbs apart.  The final check would be the ignition circuit.

This would be awsome for one of those get together things!  I would love to watch carbs getting pulled apart.  Just an idea though.  We should be able to get that done in a night, or at least taken off and inspected.

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<br />This would be awsome for one of those get together things! I would love to watch carbs getting pulled apart. Just an idea though. We should be able to get that done in a night, or at least taken off and inspected. <br />

<br /><br />Just remember, BEFORE ripping apart carbs, always make sure you have the replacement gaskets and o-rings (if required).&nbsp; Odds are, the originals won&#039;t be salvageable and you don&#039;t want to have to wait a week with your bike apart waiting for the gasket to be shipped to town.&nbsp; Don&#039;t ask how I know this.....

hey James...how do you know that???<br /><br /> ;D

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<br />hey James...how do you know that???<br /><br /> ;D<br />

<br /><br />I knew someone would ask&nbsp; :dunno:

lol its always super important to get the parts first also because then how it goes back together is still fresh in your mind.&nbsp; Also, i line up the parts in the order that i take them off when i rebuild carbs.&nbsp; to make life easier.

Thanks guys, I&#039;ll let you know what I find.

i wpould just get the gaskets and take the carb apart there is like 7 pieces to a carb and soke it in gas run a pipe cleaner<br />through the holes and blow it out with an air hose make shure to blow it out realy good and clean every thing realy good with the gas and a tooth brush and get the air nosle in every hole. but that is just me i do that alot the the old bikes i buy <br />if they have been sitting over winter&nbsp; or something.

Don&#039;t I have to re-sync the carbs once they come off??

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<br />Don&#039;t I have to re-sync the carbs once they come off??<br />

<br /><br />If they were really dirty, then you might.&nbsp; But usually not unless it really seems to be running crappy....

just a warning, i have a buddy with a 99 zx7 and his carbs were acting up so he tore them apart and soaked them in that overnight carb cleaner shit, it wrecked all the diaphragms and orings and he had to buy 4 carbs off ebay. i dont know anything about newer carbs, so im sorry if i cant get into specifics and i dont think i could answer any further questions but im hoping some one else could maybe do that for me.

QUOTE:
<br />just a warning, i have a buddy with a 99 zx7 and his carbs were acting up so he tore them apart and soaked them in that overnight carb cleaner shit, it wrecked all the diaphragms and orings and he had to buy 4 carbs off ebay. i dont know anything about newer carbs, so im sorry if i cant get into specifics and i dont think i could answer any further questions but im hoping some one else could maybe do that for me.<br />

<br /><br />+1<br /><br />Don&#039;t soak the carbs entirely...spray it out, but no soaking....