Originally Posted by Megadan (Post 286932)

The main jet does not play a direct role in fueling until right around the 3/4 throtte mark. You would be surprised at how big of a difference in main jet you can run and not be aware of the difference below that point. The main jet is the total fuel level that passes through the needle jet (emulsion tube), but the needle restricts flow through the needle jet as low as 1/8th throttle through 5/8 throttle, thus rendering the main jet size itself more or less inert until the passage restriction of the needle has opened up an area at least equal to the area of the main jet at the emulsion holes.

You could put a 110 and a 120 main jet in the same carb, on the same bike, and never know the diffrence until you go beyond 5/8 throttle, and definitely once you reach 3/4.

Originally Posted by tomrom (Post 286601)

Yes, I sent Don at apscusa.com an email last week. He called me on the phone and promised to cover all the parts. He asked that I open it up first and take some pictures. I emailed him yesterday evening so I hope to hear back on Monday. Don says they have parts at 8 different locations around the country.
He also told be he would work with a professional shop for the parts If I want to bring it someplace for repair.

I did call a shop in my area. http://www.procyclevt.com/. I was politely told that it was not personal to me but they refuse to work on a Chinese, or any 'off brand' bike. He mentioned an bad customer experience but I assume there is some animosity considering he charges thousands more for used bikes.

In actuality, this only took a few minutes to tear down and seeing that I won't need to split the case, it's going to be quick to repair.

Originally Posted by tomrom (Post 286959)

7/26/2018
A week has passed since my bike melted down and 4 days since sending pics to APSUSA.com and no parts or engine have have been sent out yet. I have spoken to both Don and Greg and both have told me they waiting to hear back from their supplier and are trying to figure out what caused it before shipping me anything. With the thought that if they simply send me replacement parts, I could end up with the same problem down the road. I have requested a new engine because this one is full of metal flake and chunks of melted piston and an exhaust because I don't know how much metal chunk flew into it and is lodged in it. It's the general consensus here and with Don that it was running lean, but why?
Hopefully this can get resolved by tomorrow and a replacement engine will be on the way.

Originally Posted by blanc12 (Post 286944)

Thanks for the info Dan.

Although you don't feel the difference, fuel is drawn through the main jet as the needle valve is raised. That is what I was getting at.