alright i think theres something wrong with my engine now definetly should have replaced the piston earlier. there is a weird ping noise coming from the cylinder when i get up to full throttle. the trail tech said i was going 48 and i kept pusing it up to 50 but i stopped because of the noise. any ideas what i could be??thanks

 

It's most likely just your Valves. They need to be adjusted. Bring it to a shop. Unless your Mechanically inclined and have a service manual do it yourself.

 

The 250 is a 2 stroke and has no valves.... Jsut reeds

It could be piston slap or pre ignition, due to wrong jetting, bad spark plug... Try this let your quad cool down start it up get as close to the jug as possible rev the engine then let off the gas fast while the engine is going back to an idle if you here the ping noise if is most liky piston slap...

Let me know what happens, also pull the plug and tell me what color and condition it is in...

 

it doesnt even have reeds but might be right on wrong jetting because its jetted to warmer wether and it was about 41 degrees today and snowing and windy. froze to death

 

You could be leaning it out at higher RPMs due to the warmer weather jetting. Pull you plug. And to be on the safe side, I would do a plug test too,

 

Hey honda400extreame go back to the Honda forum. now that we know the Polaris 250 has no valves or reeds next is to check the piston.You can either tear it down and check it or pull the exhaust pipe off and look it see if it has been slapping.Catch it before it breaks!!!

 

tbsleeper, this may be the perfect time for that Wiesco that you've been wanting[img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img]

 

tbsleeper,

What you are hearing is normal when it starts to get cold out. You can rejet bigger for the cold weather and/or also close the airscrew a turn or so. You DO NOT want to hold open throttle for long periods of time or you will burn up the piston. If your main jet is a 130 then go to a 140-145 main. The pinging is pre detonation. Lean condition. There is nothing wrong with the engine. Just rejet and you will be fine. I see that you have mods also. What is your main jet size? There should be no reason to put in a new piston as of yet. Not enough mods to make a difference. The stock one CAN handle a pipe and some engine work. It is the higher rpm's that the stocker can not handle. I would say that with the mods that you have your main should be around 160-170 for cold weather.

 

yup right on the nose my main jet is a 160 and i was thinkin of going up to a 170 for the winter and i would say it is time. so 2manytoys when i do the flywheel lightening i definetely should get the wiseco piston kit. right??thanks for the help. o ya when ido rejet can i hold it open throttle for a long time because when the snow hits around here and they dont plow i love to go rip down the main roads and ditch the cops and the dpw[img]i/expressions/face-icon-small-smile.gif[/img]

 

I would go with at least a 170-175. 175 to be safe and then close your airscrew 1 turn. Then you should be ok. I have the same situation with the snow here. Plus I pull my kids around on the sled. If you go with the trail lightening the stock would be ok but if you remove the starter and go with race lightening then wiseco is the way to go. It will rev really quick with the race lightening. You cant go wrong with the wiseco piston at any point. Even just to throw a stock bore size wiseco is good. Eventually you will have to change. It just depends on when you want to do it and how long you can handle your quad being down.