power loss top end

[radioactivenewf]

Hi guys,

I have a 96 summit with the 583. I have done some searching but found nothing. any help would be great.
The engine runs fine on the bottom end, lots of power and responsive. But when i get past 3/4 throttle it seems to be running out of fuel. It loses all power until i let of the throttle to about 3/4, then it picks back up. is there something common, like a fuel pump, or could it be the ignition? unsure of how many km's on this thing since the hood was changed. i also have not done compression check yet, but from the plug holes, the top of the pistons look fine.
In addition, i have replaced the plugs and plug caps. One other thing I noticed was it took unusually long to drop idle rpms after releasing throttle. about a couple mins it took to idle down to 2000.
Thanks for the help.

 

[Barker]

Sounds like its flooding check carb needles and seats. Also can not remember if they have rave valves if so clean them to,

 

[radioactivenewf]

Thanks barker.
I took out the rave valves, they were very dirty with carbon deposits. also tar like substance inside the rubbers. cleaned them all up. I ran gas line antifreeze through along with octane booster and water remover, after I drained the old fuel. I didn't pull the carbs yet, seems like its starving for fuel. guess i will pull carbs next unless someone comes up with something else to try. thanks again

 

[imdoo'n]

run seafoam in the gas, are you running old fuel, what main jets are in the sled, is the gas cap vent plugged. drain the gas ifit islast years. start with the simple stuff and go from there. green mung in the carb i'm thinkin, clean it before ya put a hole in the pistons.

 

[radioactivenewf]

ok an update, and thanks for the response. I did dump old fuel and added gasline antifreeze. didn't try seafoam but will look for some. I forgot to say top end is intermittent power loss. it revs to 8500 about half the time, which is too high from what I have been reading. the clutch clicker settings are set at 6 which would explain that. the power loss happens about 6500-7000. I will check the vent in the cap next. then take off the carbs. sure is good riding up here with all this fresh snow!

 

[slededjr]

Clean the carbs, clutches, and raves. Use new clean 91 fuel. Make sure everything is set right, float height, air screw, jetting. 583 is an excellent engine.

 

[imdoo'n]

check the easy stuff first, before pulling anything apart.

 

[Summiteer]

Clutches been serviced? It can seem like a fuel/engine problem.

 

[radioactivenewf]

Thanks guys. Today I pulled the carbs, found one needle was restricted. also noticed one jet was 310 and the other 320. Not sure why, is this normal? all the machines I had back in the day had the same size. Wondering if I should put I back together as is, unsure how hard it is to change jet while carb is installed.
I also dropped the clutch clickers down to #4 from #6, this helped with the over revving.

Thanks for the help