Bike dies when coasting

[SlendyMayne]

Hey everyone. So I've recently been running into a problem with my zongshen gs250. Whenever I'm riding and I pull into a stop, when I start coasting my bike dies. I can start it back up go continue riding but the same issue happens when I coast. Anyone know a possible reason behind it or a solution maybe?

[JerryHawk250]

Could be a couple of things. Idle mixture may need adjusting. Idle set to low.

[SlendyMayne]

Originally Posted by JerryHawk250

Could be a couple of things. Idle mixture may need adjusting. Idle set to low.

Speaking of the fuel screw, even when I have the screw sitting, the engine still runs.

[Adjuster]

Idle is too low but also sounds like you have other carb issues. Likely an air leak into the system somewhere.



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[ben2go]

Partially clogged low-speed jet or tight valve lash. I have experienced this, as you describe it, from both.

[SlendyMayne]

Originally Posted by ben2go

Partially clogged low-speed jet or tight valve lash. I have experienced this, as you describe it, from both.

I figured this I cleaned out the carb and the pilot jet was slightly clogged. Got it running again but the same problem occurred. I may need to get a bigger jet.

[SlendyMayne]

Originally Posted by Adjuster

Idle is too low but also sounds like you have other carb issues. Likely an air leak into the system somewhere.



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Around how many rpms should I set it to? I had it idling it at 2k rpms maybe go a little higher?

[JerryHawk250]

Originally Posted by SlendyMayne

Around how many rpms should I set it to? I had it idling it at 2k rpms maybe go a little higher?

about 1500-1600 rpms. May just need to adjust the idle mixture or check valve lash. Valves set to tight can cause this symptom.

[SlendyMayne]

Originally Posted by JerryHawk250

about 1500-1600 rpms. May just need to adjust the idle mixture or check valve lash. Valves set to tight can cause this symptom.

Still new to the Moto world. Where's the valve lash?

[humanbeing]

Originally Posted by SlendyMayne

...may need to get a bigger jet.

Those Teikei pilot jet is little bit tricky to buy locally but online shop had everything

Originally Posted by SlendyMayne

Still new to the Moto world. Where's the valve lash?

d/l TW200 manual http://www.lisaeaise.com/tw.pdf or youtube it

[ben2go]

1100 to 1200 is the actual idle speed. New riders may find it easier to start from a stop with the idle at 1500-1600.

[SlendyMayne]

Originally Posted by humanbeing

Those Teikei pilot jet is little bit tricky to buy locally but online shop had everything


d/l TW200 manual http://www.lisaeaise.com/tw.pdf or youtube it

Woah is this the bike that zongshen engine copied? It uses the same kind of carburetor.

[Megadan]

Originally Posted by SlendyMayne

Still new to the Moto world. Where's the valve lash?

Valve lash is a term to describe the gap between the rocker arm and the valve. This gap exists to account for thermal expansion of the various metal parts of the valve train, and allow the valve the ability to fully seat and seal the combustion chamber. Otherwise, it causes a number of running and rideability issues. So there is no "lash" that can be pointed to. Lash is something you set.

Given that you have a SOHC engine, you should have two caps on the valve cover, one front and one rear with big hex heads on them. These caps come off to give you access to the lash adjusters.

In order to properly set valve lash on an engine there are a couple of criteria that must be met.
1. The engine should be stone cold - preferably sat overnight or many hours.
2. The engine must be set to Top Dead Center on the compression stroke. This means that both valves are in a "loose" condition that will allow you to make proper adjustments. If you are not at TDC on the compression stroke, then you are effectively wasting time.

[JerryHawk250]

I think Megadan and humanbeing got you covered on this one.

[SlendyMayne]

Originally Posted by Megadan

1. The engine should be stone cold - preferably sat overnight or many hours.
2. The engine must be set to Top Dead Center on the compression stroke. This means that both valves are in a "loose" condition that will allow you to make proper adjustments. If you are not at TDC on the compression stroke, then you are effectively wasting time.

Found a YT video to find the TDC. Now I have to wait several hours till I go home and work on my bike. Thanks man! I'll keep you guys updated on the progress of my bike. I was losing hope for a little while until you guys came along. <3 Off topic but have you guys heard of the kymco k-pipe?