install 80cc bbk now, it bogged when throttle

[thach2264]

Hello all- 2014 Piaggio Typhoon 4t4v



Hope some of you might be able to help me. Just upgraded to malossi 80cc, now it won't run right. If I try revving the throttle, it would bogged then died if held on to it. Let it go it come back idling. But if I throttle it slowly, it'll get to like 60% then bogged. Check for leak with carb cleaner, no leak. Carb is 18mm pd18j and carb is clean.

Also exhaust is new, plus new variator and clutch.

Have tries the following but get same result

idle   35  35  35  42  42

main 75  88  88  88  88

ndl   mid mid top mid top

mixture screw is at -2 or -2.5 depend on idle size.



I am ready to tap out, any suggestion is appreciates!

[GrumpyUnk]

I think you are having fuel flow problems. If you can only get to 60% throttle, then it is possible the fuel flow is insufficient. I would also check that you cam move the slide completely to the top of its stroke. If the slide were to bind, it would tend to choke the engine, and cause misfire that could be felt as bogging.
If you disconnect the fuel line from the carb, you should get full diameter flow of fuel as long as you keep the petcock valve open. The fuel line can deteriorate internally, the petcock may not open fully, or there may be 'stuff' in the tank that restricts outflow. Inside the tank attached to the petcock is a plastic tube mounted vertically with 'screening' that is there to catch debris. If you have pine needles, rocks, dirt, etc, it can collect and impede fuel flow through the screen. If you maneuver, you may be able to see the tube through the filler, but the tank has to be mostly empty.
The petcock may not be holding vacuum, and slowly restricting fuel flow.
You should check flow from the fuel line. Get a container to catch the fuel flow, apply suction to the petcock vacuum line, and watch. The flow should be free as long as you keep the petcock open.
Check that your vacuum line is connected to the intake elbow vacuum tap, and that the carb is inserted into the rubber on elbow and is clamped properly. An air leak can cause big problems.
IOW, check the stuff that had to be disturbed to install the BBK piston/cylinder.
If you have bog at first throttle openening check the accelerator pump(if equipped) and be sure the pump is being operated when the throttle is opened. Move the throttle control and you should see a small squirt of fuel directed into the carb inlet.
tom

[thach2264]

Tom-
thanks for all the suggestions. I'll try to move the needle all the way up and will check the accelerator pump if it squirt. My fuel petcock is currently stuck open, so it's always free flowing (new one on the way). And the mess (vertical) tube going into the tank is clean and clear. Vacuum is connected to the elbow too. Will report back. Ben

[thach2264]

So just tried the needle to the most bottom and check the squirt = good. If throttle slowly, it'll go to 25% ( I marked it this time). Anything pass 25% will bogged and died if I don't let go. There's good fuel flowing because when it stop running, I can see the fuel leaking out of the carb if I don't do manual shut off.

Also I check the voltage coming out of the stator, it's only 20V max.

Questions: Does the scooter need a proper working stator and regulator for the engine to run correctly? (currently just running in the backyard with car batt).

[GrumpyUnk]

Remove the float bowl, and then the smaller of the two removable jets. If you cannot see light, use one strand of a wire brush to poke through. Sounds like the mid-range is not functional. The pilot jet handles fuel flow and if clogged it will stumble/die/etc. There are graphs on the web showing what portion of the carb is functional(mainly) at different phases of operation, which makes me think it is the pilot jet.
tom

[thach2264]

Well after $280 tips for the mechanic, it’s running as it should now. Damn guy dont want to tell me exactly how it was fixed. He mentioned that the float was not fully sealed something along those line. Because before, I though fuel was coming out of my intake because of a bad petcock, so I ignore it and just use manual shutoff.

I overlooked = $280.

So it was running too rich all these time because of the float bowl.

[GrumpyUnk]

Wish I could make $280 fiddling with a scooter carb. A new carb, budget, was about $30, so if you do 100% markup, $60. That leaves $220 for labor/taxes/etc. About 2 hours of labor at a high rate, say $100/hour.
I never earned that much, even working Y2K New Years Eve, night differential, holiday pay, etc, watching ISP servers tick into the 21st century.
Even with a poorly working petcock, fuel should not flow from the carb. I had one that was so bad fuel leaked from the air cleaner. Unfixable. Someone tried to fix it, installed odd parts(diaphragm) and it just would not stop. new carb time.
tom

[thach2264]

Tom- not a single part was replaced, maybe 1/4 can of carb cleaner.

The scooter mech is not very honest, it bothers me that he didn’t tell me exactly what he did to fixed it. So today, I was looking around and guessing what he did to fixed it. He even told me he almost throw in the towel.

Found out it was not the float bowl that fixed the bogging issue. It was the hose connected to the air filter sensor. That hose or the air filter sensor itself was somewhat clogged. I undo the hose and plug the port with my finger and the bogging came back. Scooter now can go about 45mph, have good acceleration like a 2 stroke.

We should have a list of side gig scooters mechanic locally list. At least the money will go back to our scooter community group.



2013 Piaggio Typhoon 4t4v