Pilot screw adjustment?

[ian tomo]

Just finished putting carbs back on the st1100. The pilot screws were pretty gunked with black stuff, before I cleaned them. I returned the pilots back to the settings they were at prior to the strip down, however they ranged from 1 1/16 out to 1 5/8 out. should they now be re-adjusted to the same turns out, or leave them as is. It feels better as is now, but was wondering if it would improve even more set at 1 5/8 all round.
Also in manual it says initial settings 1 5/8 final settings 7/8 out, why is there a difference?
Thanks in advance
Ian

 

[Brant]

Just finished putting carbs back on the st1100. The pilot screws were pretty gunked with black stuff, before I cleaned them. I returned the pilots back to the settings they were at prior to the strip down, however they ranged from 1 1/16 out to 1 5/8 out. should they now be re-adjusted to the same turns out, or leave them as is. It feels better as is now, but was wondering if it would improve even more set at 1 5/8 all round.
Also in manual it says initial settings 1 5/8 final settings 7/8 out, why is there a difference?
Thanks in advance
Ian

They all will be close, but not the same. Each cyl. may require a bit different setting. Those 'manual' settings are a baseline anyways. For now, unless you plan on re-syncing carbs, which require those to be adjusted to highest inch vacuum and THEN re-sync, IMO, I'd set them where they originally were.

 

[ian tomo]

I think for the time I will leave as is. However, am I right in thinking that 'adjusting to highest inch vacuum' means adjusting each carb with pilot screw to obtain the best vacuum possible on each carb, then re-sync the carbs to no#4 so the vacuums are equal?

 

[ST1100Y]

Without emission sniffer (inserted indo each downpipe) or Carbtune glass-plugs, 100% accurate idle setting isn't really easy... 'by the book' it is determined by like +/-50rpm changes in tickover/idle... so you'd need a really precise aux tachometer/rev counter attached... without that all, the previous original settings seem the best solution...

 

[ian tomo]

Thanks for the info. Borrowed a set of vacuum gauges and synced carbs, but it doesn't feel quite right. I was getting an occasional back fire when syncing carbs.
When blipping throttle, engine speed dies before returning to set idle, and I believe that is symptom of a rich mixture. I think carbs need tweeking.
I am off on a club ride out this week end so I will be able to get an accurate MPG and see!....

 

[CODEMAN1210]

2 turns out

 

[dennism]

I made a set of take-off pipes from the PAIR output fittings that bolt onto the heads. They connect into each exhaust manifold, between the valve and the exhaust manifold.

From there, it's a simple matter to use a basic exhaust gas analyzer to read each cylinder, and adjust the pilot screws to whatever you want.

Made the engine idle and run very smoothly, and together with a synch of the throttles, makes quite a difference.

 

[LarryC]

I made a set of take-off pipes from the PAIR output fittings that bolt onto the heads. They connect into each exhaust manifold, between the valve and the exhaust manifold.

Hi Dennism,
I've had rich fuel/carb issues with my 98 for the past few years and never really resolved them. Your post is the first I've seen mentioning using an exhaust gas analyzer. Can you be more specific on what you did and which model analyzer you used... Maybe some photos?
Thanks