batman wrote on 09/03/18 at 21:49:20:You have to slow the idle speed down (close the throttle by using the knurled screw on the left side of the carb ) to allow you to hear the change in rpm when adjusting the mix screw. if you screw the mix screw all the way in the bike may not stall, the idle passage splits as it enters the carb ,and the mix screw only blocks one passage , the other remains open and may supply enough fuel to keep the motor running.( the mix screw doesn't turn off the fuel ,it more a fine adjustment)
When you last did the needle spacer ,you said that you moved the clip on the needle ,this may have been a mistake , using the washers should have been enough ,moving the clip may have sent to much fuel and could be the reason your sparkplug is still covered in soot(unburned fuel) Your trying to compensate by using a 47.5 pilot jet (you should be able to run the stock 52.5) the real problem I believe is the needle jet is to high. when your on the road your at a partial throttle setting ,above idle , and below 3/4 to full throttle , your speed is controlled by the needle jet /jet needle,(the main source of your fuel) and that's your problem. If you move the needle clip back to it's stock position and the plug stops sooting , but you develop a mid range surging it won't be because of the needle , it will be because your pilot jet is now to small.The reason you close the mix screw in and hear no difference in rpm is because the pilot jet is so small the throttle plate is open farther than normal to allow normal idle speed ,and this lifts the needle giving the carb the extra fuel it needs to idle ,closing the mix screw only cuts off a part of the small amount of fuel coming from the very small pilot jet and doesn't do much to effect the rpm.(you can't hear the difference)
I appreciate your advice & help but I don't think you're actually reading what I'm writing. I 100% understand that the idle needs to be slowed down in order to hear the change when turning the air mixture screw. It has been said endlessly and you are just assuming that I'm not doing it this way. I have done this. There was no change. So I bought a new screw set for it. Still no change.
So, as suggested by someone on this thread- I moved the clip one up, to try and lean out a bit. This worked. So I left it. Bike ran well for 150kms. Then dies in the forest. It was suggested to me, by a savage owner, that I should try my smallest jet because the air mixture screw is not working. I dont know how else to say it ...BUT the screw does not work. Doesn't matter how slow I out my idle, it.does.not work.