Low idling/dying at traffic lights.

**motomatt** · 09-18-2012, 08:21 AM

I have a 2006 Zongshen single-cylinder, 125cc motorcycle. When I am idling at traffic lights (only after the engine has warmed up for a bit), the engine will die out unless I slightly rev it. Any ideas what this might be? It never dies in any other situations. Thanks!

**humanbeing** · 09-19-2012, 01:49 AM

What's ur reading? In service manual 1400 +/-100
F***ed domestic brand spark plug/ Debris in carb etc.

**motomatt** · 09-19-2012, 01:50 AM

Originally Posted by humanbeing

What's ur reading? 1400 +/-100 is recommenced in service manual.

Ok it is closer to 1200. Should I adjust the throttle on the carb?

**humanbeing** · 09-19-2012, 03:45 AM

http://walbro.com/brochurefiles/3368...g%20Manual.pdf Adjust Idle speed screw is the quick fix.
If have time taken it apart, clean OR replace the F***ed part -The kit: http://item.taobao.com/item.htm?id=5639466182
Also did u clean the air filter?

**motomatt** · 09-19-2012, 08:07 AM

Hi,
Ok thanks! I actually just got the bike recently, so I do not even know where the air filter is! But I guess I should clean the air filter and the fuel filter, and take the carb apart to make sure it is not blocked either. Any other advice?

**DanDaMan** · 09-19-2012, 07:15 PM

check hoses that look like vacume ports for EPA and repair or plug , sucking air after the carb will let bike run but will be rough/die at idle

the rubber bit that bolts the carb to the motor (that EPA ports also are located in) can leak (cracks/gaps) and cause exactly your symptoms , can be as easy a fix as ducktape to cover cracks (short term) , and high temp engine gasket silicon for longer and more heat sensitive area's

so be4 you go spinning adjustment screws and tearing down carb , have a look at rubber bit (intake manifold) and see if you suckin air

**motomatt** · 09-20-2012, 01:45 AM

Originally Posted by DanDaMan

check hoses that look like vacume ports for EPA and repair or plug , sucking air after the carb will let bike run but will be rough/die at idle

the rubber bit that bolts the carb to the motor (that EPA ports also are located in) can leak (cracks/gaps) and cause exactly your symptoms , can be as easy a fix as ducktape to cover cracks (short term) , and high temp engine gasket silicon for longer and more heat sensitive area's

so be4 you go spinning adjustment screws and tearing down carb , have a look at rubber bit (intake manifold) and see if you suckin air

Ok thanks for advice. I will give the whole fuel/air intake system a good look before I take it apart! I did adjust the throttle screw on the carb and it works for now, but I want to see what the real problem is.

**ChinaV** · 09-20-2012, 02:12 AM

Originally Posted by motomatt

Ok thanks for advice. I will give the whole fuel/air intake system a good look before I take it apart! I did adjust the throttle screw on the carb and it works for now, but I want to see what the real problem is.

Your bike was idling low, you adjusted the idle screw on the carb and it's idling fine. What's the problem? Wise mechanics always use the KISS method. KISS = Keep It Simple Stupid.

Cheers!
ChinaV

**DanDaMan** · 09-20-2012, 05:45 PM

while the kiss method works , for bikes with new parts , my bet is this bike at one time ran and idled perfectly and over time progressed to its current problem state

yes just by jacking the idle you can keep it running but it doesnt fix the problem causing the rough idle , which is likely an air leak causing it to run VERY LEAN , a problem that not even generous rejetting could cure

so worth a look at the intake manifold , as a tiny bit of "gasket maker silicon" could cease the cause of the issue and prevent engine meltdown