Well I finally got her back together. My current stats are below on jets and such. When I first hit the start button it was an instant start, choke for a sec and then she ran fine but idle was a bit low. Idle up to 1.5 rmp and she runs great. Problem is she doesn't start like that when hot after my mods. Air screws is 2.5 turns....go to 2.75 or something else?

 

If you put the choke on when hot will it start right up? If so go to 2.75. If choke does not help try to open the throttle to 1/4 on the next hot start. If it then fires right up you know your mixture is too fat.

 

Your #40 pilot will need to be set halfway between idle drops. It's a pain to do it but you should only have to do it once. With bike idling at 1300 rpm and at operating temp, turn in until idle drops, then out till idle drops again, then back in to the midway point between the drops..

Then re-analyze the hot and cold starting ....

 

I agree now that I switched to the full site and can see your mods. A 40 pilot should be more then enough fuel at 2.5. Probley too fat for a hot start.

 

The idle mix screw doesn't increment for a reason, the fraction of adjustment may be as small as 1/8 turn. Whatever it takes. As small as all the orifices are, no two bikes are going to always be identical and elevation counts too, thus the reason for splitting the differences in drops. One is the drop due to richness, the other due to leanness, the middle will cover a broad range of elevations.

I will also say don't get too wound up on keeping the idle super low. Mine idles around 1800 rpm or so, takes throttle without any problem, isn't too raucous in sound or anything, and is happy so I leave it there. Also far less likely to stall out when off road and no stall under hard braking. My 650 needs to be over 1250 to take throttle decently so I leave it there, although I could probably do a bit more with the idle mix adjustment.

 

So in with the idle mix screw is leaner and out is fatter?
She runs great except for the hot start trouble. We had temps above 90 so not sure if that played a role.
Thanks,

 

I need to check this setting again, I'm having the same problem. Cold start with choke is instant. Hot start with 1/2 throttle, instant. Hot start with choke and no throttle, instant. Hot start with no choke, no throttle, won't start.

I have #35 pilot at 5k ASL, 2 1/8 turns on the fuel screw.

 

Kid55, you are correct - in is lean, out is rich - however, knowing this gives you just enough knowledge to become dangerous to the proper functioning of your carb. You'll need to set your fuel screw to midway between idle drops, and since you're starting at 2.5 turns out on a #40 at sea level, you'll do the idle drops by first turning the fuel screw IN.

Once you understand the functioning of the pilot system, you'll understand all 5 orifices that the system presents to the air stream and how and when they flow interesting amounts of air/fuel mix..

Once you have all that knowledge, you'll know to leave the fuel screw alone. Once set as above, all that you may have to do is re-do the midway-between-drops if you have big seasonal temperature changes or move to a different elevation..

 

Here is the little "tool" I made to do-up the fuel screw..

 

klxster,
Ya. I'm learning real fast about how finicky this carb is. I'm coming off of 2 stroke racing for 20 years and those carbs nowhere near as difficult