125 engine problems, Thinking the timining is out 180 degrees

[matty_77]

Ive just recently built a 125 motor.
Ive built many in the past but this one ive had a few hastle with.
I'm thinking that the timing is out 180 degrees as Its pushing air out the front of the carby (inlet). Is it possible to get it out 180?

 

[sean01]

id say its more like 90 degree out or you have already bent the inlet valve..

magneto mark at 12 oclock, double check this with a screw driver in the spark plug hole (some magneto's have been known to be out)

then cam gear dot at 9 oclock. also make sure the cam isnt on the rock if it is then spin it 180 degrees..
you can sometimes manage to snag a perfect 180 degree out time but its hard when the valves are rocking..

if you want to check for a bent inlet valve wind the engine over till the inlet is shut and there is valve clearance and fill the inlet port with fuel and see if it leaks thru.. make sure the plug is out of the head too..

this is why i always pull an engine down on tdc, so the cam is already in the correct location for assembly