I Should Know This By Now, But... Pilot Screw

[Gene Ungar]

I'm on my 4th RD250/350 restore/refurbishment and still get confused. 

Is the pilot screw a fuel screw or an air screw?  That is, if I'm running rich on the low speed circuit which way do I turn the pilot screw to lean out the mixture?

Many thanks.

[85RZwade]

Air screw, out to lean 

[m in sc]

rule of thumb:

motor side of slide, fuel screw. filter side of slide: air screw.

out = more of whatever its regulating.

generalization setting:
fuel screws seem happiest between 1.75-3.0 out.
air screws, aim for 1.5 +/- 1/4 turn. 
beyond that, consider changing the pilot to get closer.
Basic guidance. theres of course exceptions.

[quocle603]

Remember, you're listening/looking for optimal RPMS when you turn the screws in and out. Remember to go in increments of 1/4 turns and waiting for the rpms to change.

Obviously you need to make sure you don't have any airleaks, otherwise you're going to be turning it to that.

[Gene Ungar]

Thanks for all the help, Gents.  It's almost riding season here in Houston - so I will be tuning soon.

[JB Weld]

Almost riding season? Mine is put away for the winter......

[Gene Ungar]

I ride through the late fall, winter, and early spring when the weather is cool to (Houston) cold.  That usually means temperatures no colder than the high 40s and 50s.

When it's 95 outside it's hard to convince myself to gear up for a ride.