So I've been having an annoyance that over the last year my throttle has gotten more difficult to turn and it doesn't return on it's own. I had assumed one of my cables was going bad but this weekend I disconnected both cables at the throttle and greased them up real well and still had the problem. So I go to where the cables attach to the butterfly shaft on the throttle body and disconnect the return cable to test it to see if it is the one failing. Slides real nice. So I turn the shaft to open the valve and disconnect the throttle cable and it stays open on it's own. The spring to close it is sitting properly and it didn't turn easily so it seems the problem is there is some kind of drag on the butterfly shaft through the throttle body. I don't hear the butterfly valve scraping anything. So, ideas? I'm not sure what I can do here. It is an HPI throttle body and I've contacted them to get an idea of what I can do as well.

 

Call HPI

 

Your throttle position sensor or the butterfly shaft is crudded up and most like in the area of butterfly. Does the return spring look good? That shaft normally has plenty of play. Does not need lubrication to dry up and bind. Spraying carb or throttle spray washes that black dried up gas into it and when it dries, it's worst. Only clean butterfly and area around it with cotton soaked carb cleaner

 

I figured it out last night. The DK Customs intake support bracket was rubbing against the throttle tube. I took it off, ground down the area on the bracket that was rubbing, repainted to prevent rusting, and remounted. Issue gone.