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sportsman 500??
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Posted by: 450rdr424

getting ready to work on a sportsman 500 for a guy says it will idle fine when you give it gas it breaks up real bad but never stalls it has a carb not efi. just wondering if anyone else had this. i plan on cleaning carb and going from there.

Posted by: Teufel

Check the carb to see it is getting enough fuel or too much. Also check the valve clearance. How many hours is on the machine?

Posted by: rundrave

try adjusting the throttle cable, you can also take off the cover on the throttle assembly on the handle bars. there is a ETC (electronic throttle control) that has 2 metal contacts, when they touch it causes the machine to die, these are adjusted buy adjusting the throttle cable.

Posted by: 450rdr424

thanks for the info i have the carb apart now on the bench. the guy bought a carb kit and wants that installed so i told him i would do that. everything looked good not really varnished on the inside anywhere. hope this kit works for him.

Posted by: rundrave

make sure you route the throttle cable correctly. On my 500 there is a channel along the side of the gas tank, make sure its not kinked or anything abstructing it.

My quad was acting the same way, idled great and ran great when it stayed running, but it would just randomly start acting up and i had taken the gas tank off to get to my plug, when I put everything back together I didnt route the cable right and I figured this is what caused it.

Posted by: 450rdr424

i tore the carb down cleaned it and put a new valve needle in it and it still idles fine but acts up during acceleration it is still getting to much gas i can smell it and when i put the choke on it dies out. another thing that gets me is when it is acting up i can feel it blow air back out the air box, one of the screws is missing and i can feel it blow out that hole and see the lid lift a little. any input would help thanks.

Posted by: rundrave

its the CV carb, you have to maintain a certin amount of vacuum for it to operate right.Thus making it necessary to run a lid and change the jets.
It takes resistance on the filter side of the carb to pull the slide up, not sure EXACTLY how it works but from what I can gather it has to do with velocity through the carb that pulls the vacuum to operate the slide.

These carbs are very sensative to airbox changes. I am running and HPD carb kit, and modded air box, it took some testing to get it dialed in right

Posted by: 450rdr424

i have a friend who is a mechanic at a local honda shop stopping by tonight to drop off my parts for my 450r he is going to take a look at it real quick, even when its just sitting over night i see a wet spot on the floor from where the gas is dripping out of the carb. .....thanks for the input...

Posted by: csmith3

yea ive got a friend this happend to i not sure what he did

Posted by: Teufel

Do not overlook the valve clearances - It will cause the same symptoms.
With the keihn carbs there is a secondary air intake port at the venturi -- about 1/4" dia. there is a very small jet in-bedded in the passage way. It is molede in to the body and is not replaceable. Disassemble the carb and spray cleaner through the passage and then take a small diameter wire and run it through.
Blow through with compressed air and repeat from the other direction.

When you reassemble the carb make sure the main jet and the pilot or slow jet are in the proper location- they are the same thread size and can be easily mixed up- the larger jet is the main.

Teufel

Posted by: 450rdr424

after messing with the carb i think the valve clearance is off the guy is picking it up today

Posted by: yfzrider310

Maybe check if your timing is off if your

Posted by: TravEX

Have you tried a new air filter? Mine was doing all sorts of crap when my stock air filter played out. I put a UNI on it, and no problems since.

Posted by: 450rdr424

actually found out he had a bent rocker arm and i think something else was twisted cost him over $300 at a dealership thanks for all the advice it was just something internal i didnt want to mess around with too much.....