82 Special revs high after opening throttle

[onekallo]

Hey guys. Just got the bike back together after carb clean and fuel filter install. Throttle moves freely and returns fine. Bike fires up and idles smooth.

Issue is when I crack the throttle open either at a stop or while riding the throttle itself returns to closed but the bike stays revving really high. When I let off to shift the rpm doesn’t decrease at all. If I leave the bike and gear and use the engine for braking the load will slow the engine down again back to a smooth idle. As soon as you open the throttle again it will keep revving high.

Bike is stock other than Mac 2-1 exhaust (installed by PO). Not sure of main jet size going to check in the morning.

Any help would be greatly appreciated.

Thanks.

 

[xschris]

Sync the carbs with a manometer. Do it after you adjust the valves with the motor cold. Then sync with the motor fully warm. You need to know what size pilot jets you have and where the idle mix screws are set at. Make sure the air filters are on the bike when you do this.

 

[onekallo]

Ok thanks Chris. I will get the manometer set up tomorrow after I check the main and pilot jet sizes. Is there a standard in the manual for idle mix screw? I know sometimes it is 1 or 1.5 turns out as a baseline but adjusted from there.

Air filters were/are back on for this run

 

[xschris]

I would start with 3 turns out. Make sure your idle mix screws are accessible. The 80-82 model bikes came with them capped from the factory. If yours are you will need to drill out the brass caps to get to them. There are threads on this in the forum.

 

[onekallo]

Just wanted to add that on initial start up it idles perfectly. It only will stay high after the first and every throttle input

 

[xschris]

Could any of the things I stated before. Make sure you check the carb diaphragms for any cracks or holes.