Conflicting answers to Pilot jetting...

L

lakota

Member

Apr 24, 2003

19

0

• May 8, 2003

• #1

I placed a post on a couple of boards about my Pilot circuit jetting. My bike idles really fast when first started. Then it's erratic when warm (up and down) at different times.

I got several suggestions. Some say the pilot is lean - change to a larger pilot, and some say it's rich - change to a smaller pilot.

Which one is it?

 

L

Layton

~SPONSOR~

Aug 2, 2000

896

0

• May 8, 2003

• #2

Lean.

 

M

muscle

Member

Mar 17, 2002

146

0

• May 8, 2003

• #3

lean. Also check float level

 

J

James

Lifetime Sponsor

LIFETIME SPONSOR

Dec 26, 2001

1,839

0

• May 8, 2003

• #4

Where is your air screw at? What does it do if you turn the air screw all the way in? (I assume it is a MX bike?)

 

A

A-RustyDemon

~SPONSOR~

Dec 9, 2002

152

0

• May 8, 2003

• #5

Sounds like a possible air leak. Check for an air leak in the intake boot ( crack )... at carb clamps or a loose reed cage.

 

L

lakota

Member

Apr 24, 2003

19

0

• May 8, 2003

• Thread starter
• #6

I fogot to add, it's also producing lots of "spooge". I think that is why I had suggestions that it is a bit rich?

 

L

Layton

~SPONSOR~

Aug 2, 2000

896

0

• May 8, 2003

• #7

I gave you the short answer. It is very possible that the bike is lean on the pilot or the air screw is not set properly and still rich somewhere else. Like the main or the needle.

Also A-RustyDemon could be correct. A small air leak could cause the same problems

 

S

smarttoys

Sponsoring Member

Apr 29, 2001

199

0

• May 8, 2003

• #8

There is the possiblility that the pilot is too rich. It goes like this. The pilot is too rich, so Joe Blow cranks the idle screw in really far to get it to idle when warmed up. Then when he goes to start it cold the bike idles really fast and he wonders whats wrong with the bike when starting it cold. I've run into similar problems many times in the past. Some times it's from a too rich pilot and sometimes its from a too lean pilot. It depends on the situation. Now an eratic idle when warm does sound like a possible air leak.

 

L

lakota

Member

Apr 24, 2003

19

0

• May 9, 2003

• Thread starter
• #9

I should have been more specific on the original post.

The first thing I suspected was an air leak. I have already checked the intake boot for leaks and the carb has been taken down and cleaned thouroghly, and checked for leaks at the gaskets. It had a slight gas leak and it turned out to be a cut o-ring in the bottom of the bowl. But that has been fixed.

When I say "erractic" idle, I mean that when I take a few laps on the track and stop, the idle will vary each time I stop. Sometimes it will idle so slow that it will die if I don't work the throttle. The next time it will idle very high for a few seconds, then slow down. It will also "bog" at times when I try to start off (after it has warmed up).

When the bike has been started (high idle), a minute later it calms down to an acceptable idle, it reacts to the throttle position very quickly and revs quickly, then settles back down quickly. Like it is supposed to do?

Thanks to everyone for the suggestions.

 

M

MikeS

LIFETIME SPONSOR

Jun 12, 2000

716

1

• May 9, 2003

• #10

Needle diameter could come into play. I had that on my ktm. Tried to lean out pilot (42) but we had erratic idle like you describe. I went way rich on pilot (48) then leaned needle diameter. Well idle was better but spooged and pinged...

Now I split the pilot back to as 45 and tweeked the needle diameter. Running race gas the idle is consistant and spooge is minimal. Running pump gas spooge is the same but it loads up a tad at idle and exhibits a tad hi/low idle depending how hard I run it. So I went with the setup for running hard to be safe. More heat is generated to vaporize fuel at idle when you trash it good on the track so idle may change.

 

Faded

~SPONSOR~

Jan 7, 2003

842

0

• May 9, 2003

• #11

Originally posted by MikeS
Tried to lean out pilot (42) but we had erratic idle like you describe. I went way rich on pilot (48) then leaned needle diameter. Well idle was better but spooged and pinged...

Click to expand...

Sounds like the battle I'm fighting right now! Hopefully one of my new needles (leaner at 0-1/16) will help with the next larger pilot.

Lakota, the bog off idle would make me say that you're lean.