Hi, I have a 1999 Yamaha SR125 (23,000 miles) I got it as a nonrunner, It had sat in a garage for 5 years not being used.
I have put a new battery in it,
new spark plug,
a oil & filter change,
the air filter looks good,
cleaned the carb,
new fuel,
cleaned the side stand cut off switch.
Wrapped insulating tape round the rubber between the carb and inlet, it's cracking but not all the way thru.
It starts (just, it seems to run better on a warm day, than the cold of night?).
When it's idling,
if I open the throttle normally the engine slows down and dies.
If I open the throttle a fraction the revs pick up a wee bit and the engine dies again.
I can open the throttle a wee bit, the revs pick up and then close the throttle and the bike goes back to idling.
I have the throttle stop screw about 2 full turns out, any more and it doesn't start.
The engine doesn't sound noisy eg. tappets, cam chain. But I'm used to 2 strokes, I wouldn't know what to listen for.
Can anyone help,
thanks Mark