Velocity 150cc low speed issue

[jbbrack03]

So hopefully if I can get the fuel/air mixture correct, it will get closer to 50 MPH safely without red-lining the engine? I want to get optimum performance without burning anything up. I should be getting my feeler gauge tomorrow to check the valves.

[jbbrack03]

Ok. Looks like I need a bit more help with getting the fuel mixture correct. I got my idle perfect at this point. It sits at 2K without the back wheel moving. I took it to the point that the wheel started moving and then nudged it back until the wheel stopped. So I think that I've got that part right.

As far as the fuel mixture, I'm having some trouble. It was maxing out at 8k and 47 MPH. I was advised that it needs to be hitting top speed at around 7500 RPM. So I nudged the mixture back a little and now it's screwed up. It's going to about 7000 RPM at half throttle. When you go above half throttle it starts dropping RPM. Which I believe means that it's too lean. So I turned the screw back Counter Clock Wise and I can't even get it back to where it was. It seems to have the same results no matter how I turn it. I can turn it 3 or 4 full turns to the left and it will still stay the same. I've tried just inching it along and I can't seem to get any different result.

Does the position of the Carb in the bike have an impact on adjusting it? I have to twist my carb a little bit back so that I can reach the fuel/air screw to adjust it. I'm not sure if not having the Carb perfectly vertical has an impact on how it works???

Please provide some advice on getting the fuel/air ratio correct. I'm at a loss at the moment. Thanks!

[edfr]

Yes, HAVING YOUR CARB sideways will effect the running of it. Being Sideways The Jets in the Carb Bowl are NOT COMPLETELY COVERED with fuel and it will have trouble sucking in the gas. YOU SHOULD NOT have to TILT the carb to adjust the Fuel Ratio Screw, get yourself a short screwdriver, we all do it. This way you do not POSSIBLEY create air leaks once you have everything nice and tight. But if you keep loosen the clamps to TILT it and then you may forget to straighten the carb and or Tighten it back up without any leaks.

Your engine sounds like it is running pretty good to get about 5 more mph top end you should consider a performance Variator 115mm in diameter. Yours is probably 107 in diameter, that extra diameter will allow your belt to climb another 1/4-3/8 up the Variator and that is more top end speed. You can mark your current Variator like this and see how high your belt is climbing the way it is. If the mark left is 1/4 or more your looseing some top end and you need a little heavier weights WHICH by the way will also lower your rpms to a more respectful number in the mid 7000 range.
Lefty