Have a '01 Sportsman 400 that has an intermittent tapping sounding in the engine. Tapping is similiar to tapping a pencil on a desk. It runs great, starts good, etc. I will be changing the oil tonight to see if this will resolve the issue. The oil isn't real dirty but hasn't been changed in a few years. Since it doesn't make this sound all the time is this something that a mechanic should look at? Is there an additive that I should use in the oil?

I only use the ATV around the property for hauling and mowing with a deck attachment. It doesn't get past 10-15 mph most of the time. But when I do give it gas it really takes off.

headusher

 

Its normal if it only makes the sound at idle,and quits as soon as any rpm is builds up in the slightest. Its the noisy water pumps on the singles,425,455,500s. Put one end of a stick to your ear and the other to the water bump and you can really tell thats were the noise comes from.

Water pump is the part on the side of the motor with two med black hoses coming off of it.

 

i had the same issue with my outlaw 525...its normal, i had to spend 300 bucks to find that out though...it would tap but if i pulled the clutch in a lil bit i would go away ...dont know what it was buts its normal

 

i have a 03 sportsman 500 and have a loud ticking/tapping noise comming from it, i've adjusted my vavles thinking it might be that - no difference. i brought it to two well known atv mechanics and they both tell me that it is piston slap - although i do have good compression. i will try to listen to the water pump tonight because it would make me happy to know that it's not piston slap and that it's an easy fix

 

Oh its a easy fix if its the water pumb aright because there is nothing you can do about it, just ride and enjoy the trails.