Scooterotica

Any comments on the condition of my plug with regards to mixture? Just done 30 miles at various speeds.

maybe a tad lean ?

Thanks. Ok to leave it, or adjustment required?

i would put a new plug for starters and richen your mixture a bit it looks like the pilot is rich but the air screw is lean

garry inglis wrote: ↑Wed Jul 31, 2019 9:06 am i would put a new plug for starters and richen your mixture a bit it looks like the pilot is rich but the air screw is lean

Thanks. Could you explain a little more?
Series 2 Li with a Dellorto SH1/2. The pilot jet is non adjustable and has not been changed. With the mixture screw, does it screw in or out to richen the mix.

Thanks.

The mixture screw is only really relevant at tickover / low revs.

http://www.youtube.com/watch?v=qUzu6ZkeFTw#action=share

Whether it is a fuel or air screw depends on the position relative to the slide and that will impact in which direction you turn it to richen or lean the mixture at tickover.

Looking at the plug after a run really doesn't tell you much about the condition at various throttle positions during the run. It can look spot on if you're pooling about at 1/4 throttle but go to hell as soon as you roll it on.

Google, or search on here, how to do plug chops and check your jetting at all possible throttle positions.

MightyGem wrote: ↑Thu Aug 01, 2019 8:34 pm

garry inglis wrote: ↑Wed Jul 31, 2019 9:06 am i would put a new plug for starters and richen your mixture a bit it looks like the pilot is rich but the air screw is lean

Thanks. Could you explain a little more?
Series 2 Li with a Dellorto SH1/2. The pilot jet is non adjustable and has not been changed. With the mixture screw, does it screw in or out to richen the mix.

Thanks.

The SH type of carb takes all of its fuel through the main jet,from there it is fed to the pilot jet.

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