[Coopdog12]

Hello, I have a 2004 Raptor 660 that is burning oil. It was rebuilt to 686 by the previous owner. He also claims to have put a stage 2 cam in it. Anyways, it started to burn oil pretty bad so I pulled it apart and checked everything over. The cylinder is aftermarket big bore and looks perfect, no scratches or dings. The piston and rings also look amazing, so I'm really not seeing how they could be the issue. I am new to quads but I have rebuilt other engines before so I kind of know what to look for. The jug also didn't seem to be out of spec. Wondering what some other causes to burning oil could be? What are my options to make it quit burning oil? It started to burn a bunch, like it would be off of the dipstick after 3-4 hours of riding. Thanks in Advance.

 

[DougyD19]

Check the travel path of the piston thru the cylinder to see if you notice any variances. I had a car engine that the cylinder had been bored where it had more room in the middle than at the ends and it caused excess oil usage. I'd put new rings on. Also verify piston is round.

 

[DougyD19]

Make sure the ring gaps are offset and not aligned

 

[Coopdog12]

ok thanks, I just received the new piston so i will hone my cylinder and check it. I see any defects at all in my cylinder besides there being no crosshatch left.

 

[cory52000]

it is most likely your valve guide seals