How much slack is the kx250 chain supposed to have/

Could be it's too tight.
There is supposed to be some slack in the chain.

the cam chain is usually self adjusting unless its very slack its probably ok ,if it is very slack the adjuster may be stuck or the chain may be badly worn,also check the valve timing is still ok if the chain is slack.spluttering is usually a carburation issue or an ignition issue,loose camchains just make a noise until they get so loose that they jump teeth and bend valves.

There should be no slack!, add tension until there is no noise when hot, or no play when loose. Do not over tighten it. with manual tension-er once it stops back it up and tighten the jam nut

Provided you have not been in an accident that has bent your frame,upper and lower triple tree, or forks, the only alignment you can make is to adjust your chain. If the the front wheel is not tracking with the back wheel you just have an improperly adjusted chain. On each side of the swing arm by the rear axle are two chain adjuster cam/wheels. The have numbered bump/stops. Both chain adjusters should be set in the same numbered bump/stop to align the front and rear chain sprockets and the front and rear wheel tracking. the adjusters are on the machine for the purpose of setting the amount of chain slack. Your chain should not be too tight or too loose. If you grab your chain in the middle and push it up and down, you should have a slack measurement of 1 1/4 inches from the bottom edge of the chain to the top edge of the chain. If the setting is off the best way to make the adjustment is to raise the rear wheel off of the ground. A race bike stand is very helpful for this and oiling and caring for your chain. Harbor freight tools sells a cheap rear stand for about $35 (buy the cheaper one piece non-collapseable stand). Pull out the cotter pin, loosen the axle bolt, turn both adjusters till you have the correct amount of slack and they are both set to the same number. Tighten the axle and recheck the slack. If you notice when spinning the rear wheel that the chain goes tight then slack, you have a stretched section of chain. If this is the case you should replace the chain and any worn sprockets at this time.

Typical chain slack should be about two inches from bottom edge of the chain to the top. Grabbing the chain in the middle (halfway from sprocket to sprocket) and moving it up and down. After adjusting , you should raise the rear wheel off the ground and spin the back wheel checking every 6 inches or so that the slack does not get tighter or looser. If the chain gets tighter as it goes around the sprocket it is an indication that the chain is stretched at that point and needs to be replaced.

When the door is opening the chain will be tight on one side and slack on the other. When it is closing it will be just the opposite. It is important that you do not over tighten the chain. I suppose the wrong chain could be shipped with the opener but it wouldn't be common.

There is reputed and there is actual horsepower!
A reputed 52.5 Hp for the 1990 is not right.
A reputed 57.5 Hp for the 2007 maybe right...at the crank.
You lose 8%-10% at the wheel, 5% more with an O-ring chain.
Standard KX250 would be around 42-45 Hp in peak condition. Intake mods, jets, expansion chamber and some porting changes may give you more but it's give and take...you will lose bottom or mid-range and tractibility will go out the window with a very peaky motor. Computer search KX250 forums and canvas the responses and also look for generic KX250 link's.
Cheers.

make sure the little tooth on the end of the adjuster for the chain is locked into the groove its supposed to go into and tighten it down.
Note: the chain is supposed to get loose on you but not as quickly as it is. maybe after an hour or so of cutting.
and as for it not cutting well, the chain may need sharpened.
if it has been sharpened once by someone than take it to someone esle if it is not satisfactory.

Hi there, you wont have to replace you timing chain unless your cavalier has very high miles or if it is ratteling. There is no set timing chain replacement interval. Chains are supposed to last the life of the engine. Hope this answers your question. Cheers Ben

there is too much slack in the chain. when the handle is at rest, there should be very little slack in the chain. and when you flush, don't slam the handle. also, if the handle is all the way down when you flush and the flapper is being pulled too high, leave a one link slack. and the hook that holds the chain, clamp it closed to avoid the chain getting rehooked on it.