I've had this cat for about a year now. It has developed a noise from the crank case and i'm not sure what it is. The fluids have been changed at least twice since it developed the noise and both times there were no shavings in the oil nor the filter. At first I had thought that I had spun a bearing either at the piston rod or at the crankshaft, But if that were the case i think friction would have siezed it up fairly quickly. I'm just not sure what it could be. I've posted a link for it so take a look and let me know what you think. Thanks

YouTube - 2001 Arctic Cat enigine noise

 

ive never heard a 2001 400 run like that. i personally dont know what it could be. I had a possible answer for you before i saw the video and found out it was a manual shift. The auto 400s had a nut spin loose on some ive seen and i thought that might have been it but its obviously not it. i dont know,sorry.

 

I am having a little trouble hearing the sound on my computer but I could not tell if the sound stayed constant or increased when you hit the throttle? Also have you noticed any other instances of it not wanting to "go" like when spinning the tires in mud or suddenly needing low range to pull something when high ranged use to work just fine?


Three things that comes to mind for me are exhaust rattle, the head/cam bearings OR something in your clutch.

1) I have had the baffles rust out on the inside of the exhaust and cause a weird engine rattle. Needed a new muffler to fix. (cost like $200 must be gold plated)


2) I have had oil issues on the top end of my 400 and it makes the engine sound like a diesel when idling but goes away when you rev the engine up. Had to rebuild the top end to fix this. (cost a lot more than $200)

3) In the tranny you have a primary clutch and a starter clutch. Both are held in place with bolts (one has left handed threads but I don't remember which for sure but I believe it is the starter clutch). If the primary clutch shoe plates wear too much you can get slippage (like you talked out in the video). I am not aware of them wearing enough to cause the sound I heard as I had trouble hearing it. But you may want to start with a clutch adjustment and see where that leads. You may need to adjust it several times if it is WAY out of wack.

You are correct in that you should see metal shavings if you spun a bearing. When you changed the oil did you remove and clean the oil intake screen as well? some times the metal shavings will get stuck to it OR the magnet on the drain plug.

Although it could be something more, if it were mine I would start with a clutch adjustment and see what happens. If after a while it is still there you can drain the oil and remove the right side clutch cover and check things out. Make sure something is not loose etc. A new seal to do this is about $15-$25. Depending on what you find go from there.

Hope this helps.

Swampy

 

Thanks for the input Swampy....I don't think it's an exhaust rattle, it's a lot deeper than that. To answer your question, the rattle does ramp up with the throttle which made me think the piston or cam rod could be out or spun....but again i figure if that were the case it would have thrown the rod or siezed by now....the clutch is not somthing i considered i guess i didn't realize that would make a noise like that, good thought. That would make since with the hesitation i've been seeing. I ususally just tool around on this thing i havn't really put it in the mud or roughhoused with it really, so to answer your other question...I really can't. I can say that it ususally happens only when it's cold, after it warms up theres no hesitation, I also have towed my BBQ pit around the yard with it and no abnormal hesitation there either.
I did some errands this morning and the cam chain came to mind also. I guess this issue is just gonna be one of those things i'm just not gonna know until i open'er up and take a look. I just hate tearing into somthing not knowing what i'm gonn find lol. If anyone recognizes this sound in the video or has any other ideas or has had this issue please let me know...thanks

 

Looking at the diagrams, the crank is a multi-piece affair. Could be something loose on that. I kinda thought wrist pin slap, but could be many things. Could the cam chain have too little tension and jump a tooth causing the valve timing to be off?

 

yeah getting into that crank is going to be a shop job if that's what it really is...and that's way more than $200.00 bucks lol, (as swampy put it)......there's no way i'm gonna attempt to split that block....if it were the wrist pin would that screw up the engine over time or is it not that big of a deal....and would that be a shop job to fix....

 

If it is the wrist pin, yes, eventually the rod and piston will separate. Shop or not really depends on your ability. It would require you to remove the head and cylinder.