Is there any way to check the counterbalancer to see if it is knocking without having to split the cases. I changed the oil twice a year even if it did not need it. I don't think it is the piston because it does it with a fresh topend.

 

Rods in these machine don't really knock , let me clarify , they don't knock long . Once it's knocking , its over .

This is why I suspect it either piston slap ( I know you just had it done) or the large balancer bearing . It can be checked by removing the flywheel and going into the counterbalance area , this can be done in the frame .

Two other knocks I have seen develope are when the upper motor mount is loose , or , when the gear retaining nut becomes loose behind the flywheel .

If I had to gamble , from what you are telling me , I would guess you have piston slap .

I sure hope this helps .

 

Thanks for the reply Rick it really helps. The bore is about three months old and it did it right when the piston went in(wiseco). I just wonder if the shop didn't bore it to the right clearance.What is the clearance on the wiseco for just all around riding. I will have the machine checked out at the shop. How do you tell rod knock if they don't find anything else? Thanks alot

 

Snoopy61,

Rick set mine up at .003" clearance, with the wiseco piston. This is the clearance he recommends for a cylinder that isn't ported. He says any tighter, and the piston is more likely to seize in the first few hours than not. On ported engines, he sets them up to .0035" to prevent break-in seizure. If you do a search with keyword "400", or "engine", or "rebuild", you will find posts from him addressing the setup clearances. Hope this helps. Oh yeah, it is possible to have a piston rattle from early on. If the machine shop set it up too tight, it most likely seized and the skirt collapsed, creating too much clearance. After a light seizure, it can still run ok........I know, because I ran mine several hours after a light seizure, and could still hit 60 mph. With the wiseco, a slow break-in seems to be the best route, along with always allowing the cylinder to reach operating temperature before riding hard.

Waylan

 

This is a little off the subject, but I think it is kind of cool watching people like Walexa, who a few years ago was asking for advice, and learning like most of us... Now, he is giving advice and seems to know his stuff.

Greg

 

Thanks, Greg.

And thanks for all the helpful advice in the past. I'm a preventative maintenance freak, and all this info soaks up like a sponge. I read almost every post on this forum, simply because there is so much to learn that can be applicable down the road. Too bad high school and college couldn't have been more focused on atv's......lol.

 

I do let mine warm up a while before i ride. It seems to take forever for my wife to get ready. I think I will take a look at the counterbalancer bearing then the nut behind the flywheel. Maybe it is the nut behind the handlebars.I too am a maintenance nut when it comes to the toys that is why I have never had a Polaris in the shop other than to get two new front struts replaced. A good bath and a heavy coating of WD40 goes a long way on a 4 wheeler. It is 4 years old so maybe it needs a good tear down and a check out. It just seems strange what the noise is. Rick said a bad rod will go bad in a hurry and it has done it for a while. Compression is still good so I will look at the simple stuff first. If you are reading this Greg I would like to hook up with you when you go to Broken Boe sometime. Have you heard anything about Wolf Pen. Still a lot of trails without them.