I purchased a 99 polaris sport 400 two weeks ago and I was riding it today in the snow and ice. Then I started noticing a popping noise and I thought that I had a stick caught under the atv or maby that the chain was popping. I have isolated the popping noise to the plastic cover that is on the left side of the atv. I think it is the trans cover. Also, it only does this when I start out and am going 5 to 8 mph. It stops when I get going fast. What could this be? How do I fix it. Will it hurt to keep riding it. help please.

 

That bike is extremely easy to pull off the clutch cover and take a look. Pull the 3 rear fender bolts off the left hand side, then cut one of the zip-ties off the outlet tube rubber then pull the 7 screws out and remove the cover. A noise shouldnt be hard to spot. Look for the belt slapping the cover if it's the original, also look for the clutch hitting it if the cover has had any weight put on it before. Alittle rubbed spot on the inside bottom is normal, but a big spot or gouged spot is not normal. Hope this helps,Bubba

 

Sounds like your cover is rubbing on your primary.You will need to take it off and look inside to see if it is rubbing.They warp over time or if someone steps on them.If this is it you may need a new cover.Hope this helps.

 

Are you sure it's from the left? Not to question you, there can be many things under that clutch cover that can make a pop/bang, but let me suggest this. When the front sprockets on these machines gets worn, it will jump a spline (pop) when you're starting out...nasty noise by the way. If nothing else, replacing that sprocket with a Sunstar or Sprocket Specialties unit is a great place to start. Hotseatperformance.com is where you can find the Sunstar units. Loosen the chain, you need to loosen the two rear bearing carrier bolts, and the two bolts under the rear brake caliper, then rotate the bearing housing. Using a snap-ring plier, remove the sprocket retaining snap-ring. Clean the trans splines, then lube ( I use anti-sieze) the splines, and slide on the sprocket.

With a used machine, you should probably remove that clutch cover and take a good look at everything. If you're not familiar with these machines, you can get a maintenance manual that will walk you through anything and everything. Or you can opt to have a dealer inspect/repair it for you.

 

Damn Bubba you must have ESPN.

 

CED, I guess that last one went right over my head? Ken, I was going to suggest maybe the front sprocket jumping, but you have to figure a guy knows his left from right.[img]i/expressions/face-icon-small-happy.gif[/img]

 

Just thought it was funny we were both typing our reply's at the same time.Later.

 

I have ruled out the sprockett and drove it with my hand on the plastic cover that is on the left hand side. I could feel the popping with my hand. i will pull the cover off tomorrow. Does any one know of a web site that might have pictures of what I am going to get into? any help is appriciated.

 

Check out www.partsland.com for a break down of what all is in there. There shouldn't be anything laying loose [img]i/expressions/face-icon-small-smile.gif[/img]
I had this happen once to me when i landed a jump and my foot hit the top of the quard. Try pulling up on the plastic a little. I would make sure all of the bolts are tight before taking it off. That thing is a son of a B to get back on because there are so many bolts. Most of them aren't bad but the bottom ones suck. Once inside make sure that the primary is tight. There is a rubber/plastic round piece on the inside of the cover that you should also check. I think it is just glued on. Good Luck!!!

 

If you dont find anything loose in the belt cover the next thing would be the chain in the gearcase.I had this ge t loose and had a time finding it and it is a job to change.