Venom x22, 125cc, DF125RTS, issues and fixes

BB_Mike · 08-23-2024, 04:59 PM

I am going to toss in this information that I know for future readers...

Issue 1: Bike will cut off at random.
Cause: The kill switch near the throttle is "opening" even though it looks like it is down in the run position. I suspect that a bump in the road is jarring it and causing the switch circuit to open and kill the ignition. This left me stranded for about 20 minutes once.

Tech: The stator sends a signal to the CDI (ignition) which then sends a signal to the coil, then on to the spark plug. The kill switch is inline between the CDI and the coil. The CDI output is yellow w/ black. The coil input is red w/ white. They meet under the seat in a connector. Love some hidden color changes!

Solution: At this connector under than seat, I pulled out those two wires and connected them together which means I bypassed the kill switch. To turn the engine off now, you have to turn the key to the left. Like a car, lawnmower, most any other engine driven thing that takes a key.

Issue 2: Gas tank venting leads to raw fuel in evaporator charcoal canister or a vacuum build up in tank

Cause: This is a less likely issue, but you don't have to just delete it all.
There is an inline valve between the fuel tank and the charcoal canister that is very picky about its orientation. It can often close and not allow the tank to vent air in or out. Also there is a direct gravity flow path for raw fuel to go into the charcoal canister. I think the one way valve is like a PCV valve on a car. Once the carb' pulls vacuum, it opens that valve and allows fuel fumes to flow.

Solution:
I deleted the inline valve. I replace it with a Y fitting about 8" below the tank. Orientation of this Y-adaptor install matters. The top left port of the Y goes to the tank vent (tank's front most tube), the top right of the Y port goes to the charcoal canister's ports nearest the left side of the bike, the bottom of the Y port is a new hose that you run to the bottom of the bike.
In order to prevent the raw fuel from dripping onto the ground and also to prevent the gas tank fumes from venting to atmosphere (aka my garage), I installed a fuel shut off valve at the bottom of the discharge hose to see how much fuel accumulated. I had two drops after driving with a half full tank.
Important: There is a port on the right side of the carb' that pulls air through the charcoal canister. I removed that and plugged that port with a rubber cap.

Side note: The gas tank has a 2nd tube on the same left side. It's the rear tube. It is connected to the filler area. If you over fill your tank, or drip fuel in that area it drains to this tube. Which would dump it right onto your fairing and engine. I ran a new tube out of this down to the bottom as well. I even extended the carb' bowl drain hose to get it off of the engine. These cheap hoses will get hard after getting hot. so in all I have three hoses at the bottom of my bike.

Issue 4: Exhaust manifold nuts fell off!

Cause: we all know that these bikes vibrate like crazy. I had tightened the exhaust manifold (engine front bottom). It's risky to overtighten them. You will know they come loose because it's a big ol' exhaust leak that sounds like a an old lawnmower.

solution: The bolts that stick out of the engine are M6x1.0 You can get the nuts for these at any hardware store. try to find the "mechanical locking" style. Not the nylon locking. If you cannot score those, then buy a few and use two nuts per side. Perhaps even some blue lock tight.

Issue 5: No idle adjustment at the top near the throttle
More of a nuisance really, but the the idle adjustment on the throttle cable up near the handle bar does nothing. It would be nice to adjust cold weather idle without having to get to the carb. The fairings cover up everything and are a pain to take off. I just took off the left side and it is a pain. You can reach the idle screw from below the bike.
My fix is to just run a higher than desired idle RPM in order for the bike to crank and idle easier first think in the morning.

I don't want this thread to sound like I am bashing Venom. All in all, these type issues are par for the course with chinese bikes. It just really helps to have the internet to save you hours on end of guessing trying to track down a 5 minute fix.

Issue 5: severe rattle at shifter linkage
Any RPM above 4K and the shifter linkage will rattle like crazy!
so far I just put some zip ties on the rubber boots. I want to take the bolt off that holds that shifter bar on it, but I put like 15 foot pounds into and that bolt won't budge. Ironic that some bolts rattle loose and will fall off, but others are torqued being what they should be.

There is still a new rattle above 5K RPM that is not the shifter linkage. Sounds more internal.

08-23-2024, 04:59 PM	#1
BB_Mike Join Date: Aug 2024 Posts: 4	Venom x22, 125cc, DF125RTS, issues and fixes I am going to toss in this information that I know for future readers... Issue 1: Bike will cut off at random. Cause: The kill switch near the throttle is "opening" even though it looks like it is down in the run position. I suspect that a bump in the road is jarring it and causing the switch circuit to open and kill the ignition. This left me stranded for about 20 minutes once. Tech: The stator sends a signal to the CDI (ignition) which then sends a signal to the coil, then on to the spark plug. The kill switch is inline between the CDI and the coil. The CDI output is yellow w/ black. The coil input is red w/ white. They meet under the seat in a connector. Love some hidden color changes! Solution: At this connector under than seat, I pulled out those two wires and connected them together which means I bypassed the kill switch. To turn the engine off now, you have to turn the key to the left. Like a car, lawnmower, most any other engine driven thing that takes a key. Issue 2: Gas tank venting leads to raw fuel in evaporator charcoal canister or a vacuum build up in tank Cause: This is a less likely issue, but you don't have to just delete it all. There is an inline valve between the fuel tank and the charcoal canister that is very picky about its orientation. It can often close and not allow the tank to vent air in or out. Also there is a direct gravity flow path for raw fuel to go into the charcoal canister. I think the one way valve is like a PCV valve on a car. Once the carb' pulls vacuum, it opens that valve and allows fuel fumes to flow. Solution: I deleted the inline valve. I replace it with a Y fitting about 8" below the tank. Orientation of this Y-adaptor install matters. The top left port of the Y goes to the tank vent (tank's front most tube), the top right of the Y port goes to the charcoal canister's ports nearest the left side of the bike, the bottom of the Y port is a new hose that you run to the bottom of the bike. In order to prevent the raw fuel from dripping onto the ground and also to prevent the gas tank fumes from venting to atmosphere (aka my garage), I installed a fuel shut off valve at the bottom of the discharge hose to see how much fuel accumulated. I had two drops after driving with a half full tank. Important: There is a port on the right side of the carb' that pulls air through the charcoal canister. I removed that and plugged that port with a rubber cap. Side note: The gas tank has a 2nd tube on the same left side. It's the rear tube. It is connected to the filler area. If you over fill your tank, or drip fuel in that area it drains to this tube. Which would dump it right onto your fairing and engine. I ran a new tube out of this down to the bottom as well. I even extended the carb' bowl drain hose to get it off of the engine. These cheap hoses will get hard after getting hot. so in all I have three hoses at the bottom of my bike. Issue 4: Exhaust manifold nuts fell off! Cause: we all know that these bikes vibrate like crazy. I had tightened the exhaust manifold (engine front bottom). It's risky to overtighten them. You will know they come loose because it's a big ol' exhaust leak that sounds like a an old lawnmower. solution: The bolts that stick out of the engine are M6x1.0 You can get the nuts for these at any hardware store. try to find the "mechanical locking" style. Not the nylon locking. If you cannot score those, then buy a few and use two nuts per side. Perhaps even some blue lock tight. Issue 5: No idle adjustment at the top near the throttle More of a nuisance really, but the the idle adjustment on the throttle cable up near the handle bar does nothing. It would be nice to adjust cold weather idle without having to get to the carb. The fairings cover up everything and are a pain to take off. I just took off the left side and it is a pain. You can reach the idle screw from below the bike. My fix is to just run a higher than desired idle RPM in order for the bike to crank and idle easier first think in the morning. I don't want this thread to sound like I am bashing Venom. All in all, these type issues are par for the course with chinese bikes. It just really helps to have the internet to save you hours on end of guessing trying to track down a 5 minute fix. Issue 5: severe rattle at shifter linkage Any RPM above 4K and the shifter linkage will rattle like crazy! so far I just put some zip ties on the rubber boots. I want to take the bolt off that holds that shifter bar on it, but I put like 15 foot pounds into and that bolt won't budge. Ironic that some bolts rattle loose and will fall off, but others are torqued being what they should be. There is still a new rattle above 5K RPM that is not the shifter linkage. Sounds more internal. Last edited by BB_Mike; 09-12-2024 at 03:42 PM.
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