popping and stahling

[2SlickNick]

:suspect: if you watch the last 30 few seconds the kart at acceleration will rev up and jerk and then make a popping sound followed by stahling. it does this when i dont gently accelerate.
http://www.youtube.com/watch?v=nZGTsvsJ03E&feature=youtu.be

[xlint89]

It's tough to hear what's going on with all that wind noise. Often, rapid opening of the throttle followed by stalling can be lack of fuel. Did you do any engine modifications and not adjust carb jetting?

[2SlickNick]

i did not adjust engine. I think i did however turn pilot screw on carb a week ago. I cleaned carb out weeks ago.

[2SlickNick]

when i put the kart on stands i can not acheive that popping and stalling. I think it might have something to do with load. maybe TAV again?

[2SlickNick]

Maybe I will put spring on hole 2 on driven pulley see if that does anything.

[xlint89]

You are correct in thinking the kart on the stand doesn't have the same load on the engine as actually on the road. That's when the engine will require more fuel (under load)

Here's what I suggest doing. Take another spark plug with you. Make your kart stall out on you. Install the other plug and look at the color of the one that was in it when it stalled. Let's see if that will indicate a fuel delivery problem.

[2SlickNick]

Sounds like a plan. Thank you. Will let you know.

[2SlickNick]

The old one had a brown color. it was dry. I put A new one in and it did kind of jerk a little on acceleration but did not stall. I will test it out some more. I also will adjust and check valve spring too and see if that helps some.

[xlint89]

Brown color is normally "good". What is the recommended spark plug for that engine?

[2SlickNick]

recommneded plug is ngk BR6HS. I put that in there and gapped it 0.028.
It did do it again. The driver pulley engages when i accelerate, belt starts rising but kart will not move. then i give it more gas and that is when it pops forward and will stall. I am starting to think it is driven pulley once again.

[xlint89]

Ok, cool. I was hoping you weren't using a different plug as suggested. I thought it was weird that a new plug kind of helped.

That makes sense about the pulley then. The belt should be low on the drive pulley when you take off (max torque) and start to rise as the kart starts to move up in speed, thus creating more speed than torque.

So if you're belt is starting to ride up on the drive pulley, and then engages the driven, the load may be too great for the engine to handle and could stall.

So once again, the kart on the stand (no load on the engine except for just the weight of the tires and axle) it probably spins fine. Once you add the weight of the kart and yourself, that load is too great for the engine to overcome and stalls.

[2SlickNick]

So, I need to lose weight or get a bigger engine. LOl I just have to feather it on take off with my fat ass.

[2SlickNick]

http://www.youtube.com/watch?v=eFgyICx97j0
Think maybe this is the problem???

[xlint89]

Not sure what you mean by it should have play in it? Are your pulleys properly spaced?
How far apart are your pulleys from center to center?

[2SlickNick]

i have not measured my pulleys but i am sure they are properly spaced, since it came that way stock.
maybe i need to try new bearings anyways

[xlint89]

Can you get someone to film the CVT in action while you're driving? That may give us some better insight into what's really going on back there.