hot start extreme difficulty

[noobi]

my 07 ec125, has just had a new piston and rings. and now its become very difficult to start hot. i have to put the choke on and open the throttle to WOT and kick it really hard to get any sign of life out of it.
it wasnt this hard before the new piston.
everything was fine when i did the rebuild, no bore scratches or wiggle in bottom end.
one of my bike mates suggested it could be the jetting, i dont know

its a 40 pilot jet, a 175 main jet with a N1EG on the 2nd position, air screw 3 turns out

any help would be appreciated

[widebear]

Air screw adjustment is to lean , try 1 turn out.

[noobi]

Originally Posted by widebear

Air screw adjustment is to lean , try 1 turn out.

ok, thanks

the bike shop commented on how it was happier with the air screw 5 turns out and suggested a biger pilot. does that make sense with what your saying?

[iancp5]

Originally Posted by noobi

ok, thanks

the bike shop commented on how it was happier with the air screw 5 turns out and suggested a biger pilot. does that make sense with what your saying?

5 turns out! It must be nearly falling out

If you need 5 turns out I think it suggests you need a smaller pilot. Turning it out leans the mixture. It's easy to adjust so if I was you I'd put it back to standard ride the bike and see how it behaves. You'll probably need to adjust the throttle stop to get an idle if it's setup 5 turns out.

[noobi]

Originally Posted by iancp5

5 turns out! It must be nearly falling out

If you need 5 turns out I think it suggests you need a smaller pilot. Turning it out leans the mixture. It's easy to adjust so if I was you I'd put it back to standard ride the bike and see how it behaves. You'll probably need to adjust the throttle stop to get an idle if it's setup 5 turns out.

dunno really. ill play around with the air screw tomorrow, school holidays are great for playing with bikes, and see if i can sort it out. but the report i got from the shop definately says bigger pilot

[GMP]

Five turns out is crazy. There is something very wrong to make it run better like that. How does it run otherwise, is it OK once your off the idle/pilot circuit? Did the carb come apart for some reason?

[rpduc]

If the shop is saying bigger pilot AND screwing the air screw out they've got some wires crossed...

That could have been a brain fart on someone's part.

Put in the bigger pilot they suggested and start at 1 turn out and see what you get.

By 2nd position I assume you mean second from the bottom? Because second from the top would also lean it out.

[noobi]

Originally Posted by rpduc

If the shop is saying bigger pilot AND screwing the air screw out they've got some wires crossed...

That could have been a brain fart on someone's part.

Put in the bigger pilot they suggested and start at 1 turn out and see what you get.

By 2nd position I assume you mean second from the bottom? Because second from the top would also lean it out.

no, 2nd clip from the top!?!?
the bike runs very well on and off the pilot circuitry, its just hard to start, and it wasnt like that before the new piston, it doesnt exactly rip my arms off, but its a 125 not a 450. there are no flat spots to speak off and revs up cleanly. but i dont know the difference between a well jetted bike and a poorly jetted bike. it runs and its smooth

[widebear]

Noobi.rpduc's advice is correct. The air screw's adjustment range is only 0 to approx 2.5 turns out. Half to one and a half turns out being the sweet spot. Anything either side of those parrameters will require a pilot jet change.

[noobi]

Originally Posted by widebear

Noobi.rpduc's advice is correct. The air screw's adjustment range is only 0 to approx 2.5 turns out. Half to one and a half turns out being the sweet spot. Anything either side of those parrameters will require a pilot jet change.

ok, ill invest in some pilot jets. 42?