2 STROKE WORLD .net

The 2-Stroke Garage => Turning Wrenches => Topic started by: Gene Ungar on October 10, 2020, 09:17:56 AM

Title: I Should Know This By Now, But... Pilot Screw
Post by: Gene Ungar on October 10, 2020, 09:17:56 AM
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. :clap:

Title: Re: I Should Know This By Now, But... Pilot Screw
Post by: 85RZwade on October 10, 2020, 09:41:32 AM
Air screw, out to lean  :wave:
Title: Re: I Should Know This By Now, But... Pilot Screw
Post by: m in sc on October 10, 2020, 10:18:12 AM
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.
Title: Re: I Should Know This By Now, But... Pilot Screw
Post by: quocle603 on October 12, 2020, 11:08:54 AM
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.
Title: Re: I Should Know This By Now, But... Pilot Screw
Post by: Gene Ungar on October 13, 2020, 04:35:54 PM
Thanks for all the help, Gents.  It's almost riding season here in Houston - so I will be tuning soon.
Title: Re: I Should Know This By Now, But... Pilot Screw
Post by: JB Weld on October 27, 2020, 07:11:32 PM
Almost riding season? Mine is put away for the winter...... :harley:
Title: Re: I Should Know This By Now, But... Pilot Screw
Post by: Gene Ungar on October 28, 2020, 10:12:02 AM
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.