cam chain noise???

jay1 · Apr 2, 2011

hey guys need some help with what i think is cam chain noise.I have just rebuilt the top end on my Orion 125 pit bike,new piston,rings,valve seals etc.started the engine, fired up first kick ran great but was making a kinda ticking noise,so i checked and adjusted the valves again but still makes the same noise,sounds like it's coming from near the back of the engine so i thought it's the cam chain tensioner but found out that they are automatic,so there is no manual adjustment.Have i missed something when putting the engine back together??

sean01 · Apr 2, 2011

did you pull the chain tensioner out when you had the engine apart? if so double check you put it all back in the correct way..

double check your cam timing too

jay1 · Apr 2, 2011

yeah i pulled the chain tensioner out when i had the motor apart,but put it back in the same way it came out so i think it's right.I think the cam timing is correct,followed some info on how to do it i found on the net.If the cam timing is wrong wont the bike not run properly.bike runs fine just noisy

sean01 · Apr 2, 2011

if its 1 tooth out it can still run close to fine.. it will either have really good take off or have really good top end..
i built a 200cc china engine a while back and it was hard as hell to kick start.. i advanced the cam timing by a full tooth and it was just like a stocker to start and also brought the power-band of the cam lower down the rev range.. just wasn't as torque y

with the piston at the top of the stroke the cam dot will be at 9 o'clock.
easiest and most recommended way to find tdc is to remove the spark plug and use a screw driver to carefully feel the piston as it comes up to the very top.

jay1 · Apr 2, 2011

just rechecked the cam sprocket and the cam dot is at the 9 o'clock position as well as the T mark on the fly wheel is lined up with the mark on the housing with the piston at TDC