piston sound like knocking...

[tipistroy]

Hi, I'm new here and new owner of a ktm 505 sx! the quad is running fine but theres a sound coming from de cylinder and its sound like the piston is loose inside! one of my friends think its a piston slap... can hear on idle but more you rev more you hear that sound... I already chek the cam chain tenssionner and is good! what you guys think?

[5lblmbn2009]

could be crank bearings. start easy though until you decide it is something. check the valves. is tit he stock tansioner or an aftermarket one? some say the stock one isn't that great. did you get told the number of hours on it when you bought it?

[ktmbill]

Drain the oil if you see metal and copper in the oil all so check your clutch basket it may be cracked

[tipistroy]

Like i said the valves and cam chain tentionner is suppose to be alright because i had it done last week but I still have that sound coming maybe more around the clutch and when i did the oil change last weekend it was some kind of little metal piece realy realy mini

[tipistroy]

And i bought the bike at 25h and i probably did 2h with.. Never been race I bought it from one of my friend, oil change have been donne every 4h

[5lblmbn2009]

it could be the normal noise unless it has gotten noicably louder or different.

[997GT3]

Like i said the valves and cam chain tentionner is suppose to be alright because i had it done last week but I still have that sound coming maybe more around the clutch and when i did the oil change last weekend it was some kind of little metal piece realy realy mini

Your connecting rod big end bearing is shot.I had the same problem and saw small copper colored metal shavings during an oil change.These shavings are from the big end bearing.Replace it pro x rod/bearing kit from Rocky mountain atv.

[tipistroy]

I dont think is copper collor... Its more like silver... And i just came back from a 4 hour run in the snow! The bike still working awsome and have lots of torque! But still doing that sound.. I will check the clutch basket next week to see if it still good or not! And by the way I got a brand new piston and ring set ready to be instal just in case its the piston.. Its a wiseco piston kit

[997GT3]

I dont think is copper collor... Its more like silver... And i just came back from a 4 hour run in the snow! The bike still working awsome and have lots of torque! But still doing that sound.. I will check the clutch basket next week to see if it still good or not! And by the way I got a brand new piston and ring set ready to be instal just in case its the piston.. Its a wiseco piston kit

Why ride the bike without figuring out the problem? Metal shavings in the oil and you are asking for trouble by continuing to ride on.But hey it's your bike and money lulz...

[MortQ77]

Yep...I wouldn't be riding it with a noise like that! But your call. I suffered a similar noise and it was defn piston slap. Have you got a compression tester?

[tipistroy]

I know I should not ride it.... I dont have a compression tester but one of my budy have one! thats something we gonna check to!

[5lblmbn2009]

he said there was one mini chip of metal guys. if it was just really small it could just me normal wear. the bearings would be copper colored shavings. the silver is probably just normal transmission wear and if there is one chip i wouldnt worry about it unless it was huge... the noise though you should figure out if it is much worse than it used to be, but if it was like that when your friend bought it then it is the normal noise. should upload a video. did it start right after you adjusted the valves?

[tipistroy]

when i bought the bike it was doing that sound, the guy told me the valve ajustment have to be done, so I took the bike to a ktm dealer and they dide the valve and cam chain tenssioner, and I never seen copper in every oil change... just silver metal wear... we use a stethoscope just to try to hear and it comes from inside the clutch cover.....

[ktmbill]

Is it metal or aluminum use a magnet if it is aluminum its the clutch basket it will crack make noise like the crank is knocking it will get worst and blow up and take your case out and a lot of other stuff and if you let it go long it will take out your rod

[5lblmbn2009]

yea you need to check the basket if it is aluminum as bill says. there is also a nut in there that you should check and make sure it is tight and if not torque it, it also has one on the stator side you could check. I am sure the sx could have the problem too, but the xc's i know have a problem with one of them.

[kiwi-craig]

silver stuff is the rod main bearing eating itself……….

[tipistroy]

i got the engine open last night and the connecting rod big end bearing is shot.....:S it is bettter to juste change the rod or change the hole fuckin crank....? the guy ho do my mecanics told me its better change the crank...$$$$$

[997GT3]

i got the engine open last night and the connecting rod big end bearing is shot.....:S it is bettter to juste change the rod or change the hole fuckin crank....? the guy ho do my mecanics told me its better change the crank...$$$$$

No need to replace the crank unless it's damaged.You can buy the connecting rod,pin and bearing.I would also replace the 2 crank main bearings while your in there.Good luck..

[tipistroy]

No need to replace the crank unless it's damaged.You can buy the connecting rod,pin and bearing.I would also replace the 2 crank main bearings while your in there.Good luck..

I been told it was pain in the ass and way easyer to change the crank... But it is hard to change (rod and bearing on crank) or it have to be rebalance or anything...?

[ktmbill]

Cost of crank $1000.00 cost of a Pro X rod kit $125.00 labor $110.00 if they have the right tools and I think that Falcon charges $250.00 labor
So I would say it's easier to change the crank but harder on the wallet so it"s easier to do the rod because it's a bitch to make money