carburetor spitting

[Ahmedy]

Hi there fellow motorized bicyclists. I'm thinking of making a valve between the carburetor and the engine by using a solenoid and some electrical equipment to control it. The idea is for it to open when the engine draws the air fuel mixture through the carburetor, then close during those times of back pressure. Thus it would cancel the problem of fuel being spat out through the carburetor. This is just theory . I know I think of the wildest things so this might not be practical. I know one things for sure that the solenoid has to work very fast. Basically at the same revs as the engine.

 

[Agreen]

Reed valves already exist for that purpose.

 

[Ahmedy]

True. My only problem is getting a reed valve. There aren't many bike shops here that can offer parts at reasonable prices. That's why I was thinking of building something.

 

[2door]

Unless you just like to tinker, which a lot of us do, reed valves would be far less complex and fool-proof. Blow back through the carb is normal for a piston ported 2 stroke engine. It has always been a problem which is why reeds are used.

Check around on the Internet and I think you'll find sources for reeds and manifolds to work with them. You can also try our 'Search' here. Type in 'reed valves' and you'll have some reading on the subject.
Good luck. And let us know if you try your electric concept.

Tom

 

[Ahmedy]

I've read some articles on reeds. How they made and their existence. Its just if I have to import one it will probably cost me more then what I've paid for my bicycle kit. Import duties are gone terrible here in south africa.
I do like tinkering so I'll try figuring something out. Seen some videos on how they use arduino pc boards on solenoids. I'll look into it. Maybe I'll end up looking for a used reed valve from an old Aprillia or Honda. But thanks for the input . Much appreciated

 

[Agreen]

In that case, i get why you would want to try that.

Concerns:
1)It's complex.
2)Power consumption vs. generation
3)Can the solenoid open far enough at that speed to allow significant air flow?

My bike motor runs at 9000 rpm. Most will run less. That means in 1 second, it makes 150 revolutions. So your solenoid at max rpm would need to support 150 Hz. Idle air control valves (on cars) do that, and it's not unreasonable for them. But they're only letting a small amount of air past to supplement the small amount of air that leaks around the throttle. Probably not enough to support keeping a 2 stroke running.

Now, if you looked in to what it would take to make a reed valve, that could be a little more productive. I'm sure you could find some thin spring steel there to make the reeds?

 

[crassius]

not sure I see the problem here, as all 2-strokes spit back into carb

seems keeping the air filter wet helps stop particles from getting into motor

these are crappy, chinese motors, but are great for what they are if left alone

 

[Ahmedy]

A reed valve would be easier to make , no doubt. I have thought about the distance it must open and the speed it needs to do that . Also how to program such a thing would be difficult. I guess the thought was good but building such a thing not so good