I am having problems pin pointing what my problem is and was hoping for some suggestions. 2002 400 4x4 scrambler. At low speed I hear this knocking noise as I drive as my speed increases the knocking noise gets faster and at about 1/2 throttle it goes away. I can also feel this in my right floorboard. It only happens when I am moving, i have had other people ride it slowly while I look underneath but I cant notice anyting. Strange though it doesn;t happen all of the time.

Any ideas would be great

 

my scrambler used to do they same thing... i traded it in and got a pred..

 

LOL!!! My 250 trailblazer knocks sometimes hozed...so the only fix is to buy a pred....hmmmmm im gonna tell my dad that and maybe it will work.

 

You might be in need of a new top end, sounds like piston slap... I would go easy on it, you might crack the piston.. I would take the intake off and have a look at the piston before riding it hard...

 

Sounds like it could be the bottom end or the clutch. If I were you I'd tear it down and find the problem before something more damaging happens.

 

Thanx for the suggestions, I don't think that it is a top end or a bottom end though, because the only time it happens is when the quad is moving, I can rev it up with no noise or problem, it idles great. I would like to investigate the suggestion of something wrong in the clutch. Could it be improper tightening od the piee with the spring behind it (i'm not sure what it is called). Any other suggestions would be greatly appreciated.
ps I don't want a pred, no reverse, no 4x4

 

I had the same problem on my 04 scrambler execpt it was on the left side if you were sitting down on it. It turned out I burnt a hole in the belt(trying to tow) and every time it would turn it would cause a slaping noise at low speeds. at high speeds it didnt make it, i guess the belt was going fast enought to just fly over.......... you could actually feel something hit the pvt casing at low speeds too............dont know why but high speeds it was a ok!

 

lol.. well i am sure you can fix it w/o buying a pred... i was just stating thats what i did so i never found out what the knocking was...
i took it to the dealer to have them look at it.. they said everthing was fine and that i am hearing things... i was pissed considering my buddy works at the dealer and had heard it first hand himself. i thought it was something in the rear end when mine was doing it... but the bearings and everything were fine.

 

i had this problem a few month after i got my quad. look at your chain and roll it slowly look for missing o-rings. if u loose one it will keep getting worse and u will loose more and it will tear up ur sprocket. i lost 5 in a row and it ate all teh teeth off my sprocket but luckily it was under warrenty.

 

I never even considered the chain as an option, I will look at more closely, the last thing I need to do is buy a new sprocket, thanks for all of the great suggestions.