A little help please

[bucky007]

I just purchased a kuzuma 90cc atv for my son at a yard sale and it needed a carb. I put a new one on and a new battery. It cranks and runs great at first but when it gets warm I have to close the choke about half way for it to continue running then after about five or ten minutes he has to park it and has to wait for it to cool for it to run properly. If anyone can help it would be great.

[halifax]

Hey,
It sounds like you are not getting enough fuel, maybe kinked hose, or partially clogged hose or the gas line is getting to hot and turning into vapor after the engine heats up.


Aubrey

[yesitbreaks]

be sure drain line is on carb or this will be last work you do on it. big boom.
1. let him run it til it quits
2. take flat tip screw driver and open drain screw (lowest on side of carb)
3. if fuel runs out fast non stop it is not a fuel restriction.
4. if it does not run out fast it is time to move up stream
5. LET COOL OFF before doing this next thing. AFTER COOLED OFF pull fuel line off carb
watch the stream. if stream plays out quick you may have a kidney stone. no wait a fuel blockage. the fuel line on these seems to be a vacuum line and melts with ethanol. i use automotive fuel line and it does not come in this size. so i go 1/4 inch and put a band clamp on each end but you have to be careful to push hose all way on and clamp as far up on barb as possible.
best guess is a restriction in the fuel line at the barb
we have had 5 of these chinese atvs in the last 6 months.
i acutally paid for 2 of them. used 2 for parts. got a big frame 2007 kazuma for my kid for christmas and had noting in it. i love them always same problems.
anyone having problems here is the short list
1. fuel line crumbles into carb and stops it up. (i take the jets out of the carb and clean all the tiny holes with a #80 drill bit and it has worked one every carb i have tried on
2. fuel line crimps or puckers on inside at tank barb in bend
3. ALL battery cable ends fail on both ends. that is 6 ends reclaced with crimp on end terminals per bike.
4. batterys are bad and fail can be got on ebay about $20 with shipping included
the above have been required on all 4 of the chinese atv i got running (5 was for parts and i had no plan on fixing it)

[yesitbreaks]

if by chance when the atv gets hot and will not run AND you have good fuel supply then
it is hard to restart like the battery is dead
try jumper cable. just keep running and trying to jump it off over and over.
if it hard to jump off check the valve lash.
DO NOT ADJUST at random.
on the left hand side of the engine (as sitting on it) there is a round plug about the size of a nickel. you can remove it with a flat tip screw driver or a nickel. this is where the timing mark is located. there will be a mark at the threads of the crank case and a "T" next to a line on the fly wheel inside the hole. If you bump the starter untill the t lines up with the mark i guarantee that 19 times out of 20 you WILL be in the wrong position and will mess up your valve adjustment. DO NOT ADJUST NOW.
on the cylinder head there are two big plugs that look like oil fill plugs, usually a 17 MM wrench will fit them. Do not loose the o ring on these plugs or the timing plug. you can reuse them if they are not broken. if you put them back on and they do not leak they are good. DO NOT FIX WHAT IS NOT BROKEN.
Ok you are almost ready to figure out how to adjust
Bump the starter with the valve covers off (big filler plugs you took out w/ 17mm wrench).
the rocker arms will move up and down.
bump and watch when the rockers kick up out of the hole the valve is closed. when the rocker is down the valve is open.
Bump the starter until the "T" in the hole is visible.
if the valve on top of the head is down in the head it is open DO NOT ADJUST you are one revolution out. i guess it would be easy to pull the small side cover below the timing hole and use a socket and wrench to turn the crank shaft until the t is lined up and the valve is closed but i cheat and if i tell you my cheat you could screw something up easy.
Ok when the valve is closed and the "t"is lined up try to push the rocker arm up and down if you do not feel any slack it needs adjustment. Break the nut on the rocker with a 9mm wrench about a half turn. try to push the rocker up and down. if you have a little slack (valve lash) hold the little square bolt head in the middle of the 9mm nut in place WITHOUT LETTING IT TURN (usually easy to hold with very small vice grips) and re tighten the 9mm nut. Check the lash again if you have a wire type feeler gauge you can use that to measure lash between the bolt and top of the valve.
At this point i try to spin over and crank but shut off at once to keep oil in the engine.
Now do the other valve the same way.
To much lash will sound like a sewing machine (valve chatter) when it is running.
Way to much lash will not run.
if it lights off and runs plug everything up and drive it.
valves to tight on the one my son is driving make it act like the battery is very week or the starter is dragging.
All info given is free please have someone else in here proof read it and see i have not had a brain fart or something before you use it.
if you mess it up please do not blame me.
my kid does not notice valve rattle.
on his first atv he drove by with a terrible rattle and ask "is that important or is it something you can weld later?"
i told him it was to dark to find but if it quit go back and find what fell off.