Randomly dying at idle.

[ninskrillz]

Hey guys, gotta little annoyance I've been dealing with since I first got the bike to run. Every once in a while, seemingly randomly, it will kinda sputter for a split second after warming up. If I don't pepper the gas immediately it'll die. This seems to only happen after it warms up. I dunno if this has anything to do with it but sometimes the idle will stay at 1350 or so after coming to a stop. I'm running a Pamco with e advancer and vm34 carbs.

 

[Marlin72xs]

I've got stock carbs, but mine used to slowly climb up at a light occasionally, then it would do what yours is doing. Idle properly, then sputter and die. Had to have ur hand on the throttle at all times.

Found the low speed jet screw in almost all the way on one carb. Set em right and now only climbs once in a red moon.

Good luck!

 

[pamcopete]

Hey guys, gotta little annoyance I've been dealing with since I first got the bike to run. Every once in a while, seemingly randomly, it will kinda sputter for a split second after warming up. If I don't pepper the gas immediately it'll die. This seems to only happen after it warms up. I dunno if this has anything to do with it but sometimes the idle will stay at 1350 or so after coming to a stop. I'm running a Pamco with e advancer and vm34 carbs.

Lean mixture is one of the causes of an increase in RPM's. As it gets progressively more lean, eventually it is so lean that the engine stops. I would start by checking the fuel level in the bowls which you can do with the carbs on the bike using a clear fuel line attached to the drain spigot and held up to the side of the carb.

 

[ninskrillz]

I've got stock carbs, but mine used to slowly climb up at a light occasionally, then it would do what yours is doing. Idle properly, then sputter and die. Had to have ur hand on the throttle at all times.

Found the low speed jet screw in almost all the way on one carb. Set em right and now only climbs once in a red moon.

Good luck!

Carbs are all synced up unfortunately don't think that'll help me thanks anyways!

Lean mixture is one of the causes of an increase in RPM's. As it gets progressively more lean, eventually it is so lean that the engine stops. I would start by checking the fuel level in the bowls which you can do with the carbs on the bike using a clear fuel line attached to the drain spigot and held up to the side of the carb.

I'll try this, how can I tell if the level is appropriate? The floats are both adjusted properly to 23mm

 

[weekendrider]

Pete was assuming you have OEM carbs, (I think).
The way it done with OEM carbs is like Pete said.
Attach a clear gas line to the bottom(34's make it easy you have a nipple to slip the hose on) and running the line next to the carb open the petcock and fill the bowl. The level will show in the clear line and should be at the lip of the carb body.
Since adjusting the VM 34's is measured from the gasket rib on the throttle body I would assume it would put the level right at the bottom of the carb body like the OEM's?
But where and what you use to replace the float bowl drain plug. Maybe buy an extra and fix a nipple to it for the gas line?

 

[pamcopete]

Carbs are all synced up unfortunately don't think that'll help me thanks anyways!

Lean mixture is one of the causes of an increase in RPM's. As it gets progressively more lean, eventually it is so lean that the engine stops. I would start by checking the fuel level in the bowls which you can do with the carbs on the bike using a clear fuel line attached to the drain spigot and held up to the side of the carb.

I'll try this, how can I tell if the level is appropriate? The floats are both adjusted properly to 23mm

weekendrider has pointed out that you do not have stock carbs...bummer. You could try removing each bowl very carefully to check the fuel level while there is still gas in the bowl. As a minimum, both bowls should have the same amount of gas. You may be able to do something similar by opening the drain plug and catching the fuel from each carb and then compare the amount. Should also be the same for both carbs.

When you quickly mentioned that the float levels have been set to 23mm, it sounds like you recently did that, so that brings us to the universal trouble shooting axiom..."what did you do to the bike most recently?" because that is usually where the problem lies.

 

[ninskrillz]

Carbs are all synced up unfortunately don't think that'll help me thanks anyways!

Lean mixture is one of the causes of an increase in RPM's. As it gets progressively more lean, eventually it is so lean that the engine stops. I would start by checking the fuel level in the bowls which you can do with the carbs on the bike using a clear fuel line attached to the drain spigot and held up to the side of the carb.

weekendrider has pointed out that you do not have stock carbs...bummer. You could try removing each bowl very carefully to check the fuel level while there is still gas in the bowl. As a minimum, both bowls should have the same amount of gas. You may be able to do something similar by opening the drain plug and catching the fuel from each carb and then compare the amount. Should also be the same for both carbs.

When you quickly mentioned that the float levels have been set to 23mm, it sounds like you recently did that, so that brings us to the universal trouble shooting axiom..."what did you do to the bike most recently?" because that is usually where the problem lies.

I've been dealing with lots of little things, so measuring float height was a part of diagnosing other problems that have been solved. Didnt actually have to adjust them. Pete you helped me figure out my small battery causing hard starts could a small battery cause this?

 

[pamcopete]

nins...,

Not if you have replaced the small battery as suggested!

OK. Here goes an off the wall theory. This happens during idle, so at idle the small battery is slowly discharging, perhaps to the point where it affects the operation of the E-Advancer and causes an increase in advance timing which would then cause the engine to speed up until the small battery voltage got so low that the ignition no longer worked and the engine died. So, yes, the small battery could cause this condition. If you caught it in time and revved the engine, the E-Advancer would then work properly, the small battery would recharge some and the whole cycle would repeat.

 

[ninskrillz]

nins...,

Not if you have replaced the small battery as suggested!

OK. Here goes an off the wall theory. This happens during idle, so at idle the small battery is slowly discharging, perhaps to the point where it affects the operation of the E-Advancer and causes an increase in advance timing which would then cause the engine to speed up until the small battery voltage got so low that the ignition no longer worked and the engine died. So, yes, the small battery could cause this condition. If you caught it in time and revved the engine, the E-Advancer would then work properly, the small battery would recharge some and the whole cycle would repeat.

Unfortunately the battery tray won't allow for a full sized batter unless you have some suggestions for sealed batteries.

 

[pamcopete]

nins...,

Try wiring a full size fully charged battery to the bike with the PMA disconnected as you did before and see if that cures the latest problem.

Batteries can be wired up in parallel, so you could wire two 5 AH batteries in parallel and locate the second battery anywhere on the bike because you do not need battery sized cables for those tiny batteries with a kick start setup. You can just use 16 gauge wire for greater flexibility to install the batteries wherever. Use three batteries for a grand total of 15 AH.

 

[ninskrillz]

nins...,

Try wiring a full size fully charged battery to the bike with the PMA disconnected as you did before and see if that cures the latest problem.

Batteries can be wired up in parallel, so you could wire two 5 AH batteries in parallel and locate the second battery anywhere on the bike because you do not need battery sized cables for those tiny batteries with a kick start setup. You can just use 16 gauge wire for greater flexibility to install the batteries wherever. Use three batteries for a grand total of 15 AH.

can the reg/rec be unplugged while the bike is running?

 

[figure8]

Yes you can.

 

[ninskrillz]

I tried cutting the rectifier to see if that would help to no avail. Can't really afford to buy more batteries for testing. Any other ideas as to what might be causing this issue?