Carb Pilot Screws - to remove or not to remove

[Oldschool1]

How important is it to remove and clean the pilot circuit?

I would just do it if I had the magic D sape SST or could make something to fit it.

But considering this holds me up for another weak on the driver and considering the carbs were really clean relatively can i ignore them, or can i clean the circuit with them in place?

Previously the bike ran good - the only quible would be +-50 rpm oscillation at idle and if idling in first gear you get a bit of jerk. Would pilots cause this or more the idle jets - which were very minor obstucted.

Thoughts?

Thanks,

Paul

 

[Mark]

If you have them out there are two items you can use that are probably easy to get...
A strand from a bbq brush... brass! Brass will not hurt the jet's metal; or, monofilament fishing line. I just push it through the hole.

If it started and you didn't have to keep it rev'd to run the slow speed jets might not be clogged...
If you don't manually clean them I'd run some Berryman's and/or seafoam for a couple of tanks.

 

[BuddingGeezer]

How important is it to remove and clean the pilot circuit?

I would just do it if I had the magic D sape SST or could make something to fit it.

But considering this holds me up for another weak on the driver and considering the carbs were really clean relatively can i ignore them, or can i clean the circuit with them in place?

Previously the bike ran good - the only quible would be +-50 rpm oscillation at idle and if idling in first gear you get a bit of jerk. Would pilots cause this or more the idle jets - which were very minor obstucted.

Thoughts?

Thanks,

Paul

Use plastic tubing with the ID same as pilot screws. Slip it over the screw and screw them out or in. Allways before removing, screw them in and count the turns, then remove. Now you have a setting when you put them back in.

 

[Oldschool1]

Use plastic tubing with the ID same as pilot screws. Slip it over the screw and screw them out or in. Allways before removing, screw them in and count the turns, then remove. Now you have a setting when you put them back in.

Very nice idea on the plastic tubing - i should be able to make that work. I'll count the turns. Being a California bike (I heard CA bikes are set too lean due to emmisions mania!) - is it prudent to put them back in the exact same or slightly richer? Or should just put back exact and then tune them per the manual at startup?

Thanks,

Paul

 

[Mark]

Note that I was thinking 'jets' when I read 'pilot'...
sorry.

Mark

 

[GitSum]

Once you get them out, take a dremel tool with a cut off wheel and cut a slot for a screwdriver

 

[Oldschool1]

Well I'll be a bit detained on the pilot screws as my plastic tube slipped and I lost count of the initial position (arggghhhh), The other 3 are however in original position (at least i haven't moved them).

I'm trying to find a D shape driver for the other 3 screws - will resume when i get one of these. Motion makes a $3 bit but i here you would have to turn down the hex/sqare end to not interfere with the float bowl edge (oh Honda - why why why!).

Pilot circuit flushing:
After i do get the screws out - is the reccomended cleaning just a squirk of carb cleaner - let it soak a day then blow out through the pilot screw hole with 100 PSI? Will I have to remove the pistons and boots to prevent overpressurizing the diaphrams?

Thanks,

Paul

 

[Oldschool1]

Well I'll be a bit detained on the pilot screws as my plastic tube slipped and I lost count of the initial position (arggghhhh), The other 3 are however in original position (at least i haven't moved them).

I'm trying to find a D shape driver for the other 3 screws - will resume when i get one of these. Motion makes a $3 bit but i here you would have to turn down the hex/sqare end to not interfere with the float bowl edge (oh Honda - why why why!).

Pilot circuit flushing:
After i do get the screws out - is the reccomended cleaning just a squirk of carb cleaner - let it soak a day then blow out through the pilot screw hole with 100 PSI? Will I have to remove the pistons and boots to prevent overpressurizing the diaphrams?

Thanks,

Paul

Update - well orded the motion pro - d shaped bit then ground the hex head off of it so it would clear the carb body then bonded it to an alumimum rod woth thick cyanoacrylate (crazy glue).

So screws out and number of turns:
1) unknown - lost the turn count when my plastic tube slipped
2) 2 3/4
3) 2 1/2
4) 2 3/8


So i may guess at just setting #1 screw at the factory suggested 2 3/4 turn.

For cleaning the pilot circuit i scraped with my fingernail the residue off of the pilot screw needs - seems good there.

For the circuit - i was just going to spray some carb cleaner in the screw hole - apply a little compressed air - see where it goes. Repeat until i can get in through the circuit then let it sit over night - repeat - blow out with air.

Any thoughts on this? I have not removed the diaphram slides as i would rather not tinker with them.

Thx,

Paul

 

[Brant]

Update - well orded the motion pro - d shaped bit then ground the hex head off of it so it would clear the carb body then bonded it to an alumimum rod woth thick cyanoacrylate (crazy glue).

So screws out and number of turns:
1) unknown - lost the turn count when my plastic tube slipped
2) 2 3/4
3) 2 1/2
4) 2 3/8


So i may guess at just setting #1 screw at the factory suggested 2 3/4 turn.

For cleaning the pilot circuit i scraped with my fingernail the residue off of the pilot screw needs - seems good there.

For the circuit - i was just going to spray some carb cleaner in the screw hole - apply a little compressed air - see where it goes. Repeat until i can get in through the circuit then let it sit over night - repeat - blow out with air.

Any thoughts on this? I have not removed the diaphram slides as i would rather not tinker with them.

Thx,

Paul

Not a good idea! You'll likely damage the floats.

 

[vinny]

I have not removed the diaphram slides as i would rather not tinker with them.

Not a difficult task, just remove the four screws on the cap and slide them out.

 

[BuddingGeezer]

Before using carb cleaner, you MUST remove ALL rubber parts. There are o-rings that the pilot screws go through. Make a little wire hook to fish them out. REMOVE the diaphragms. Carb cleaner dissolves rubber. Get all the rubber parts out, remove the floats and spray the heck out of the carb bodies. Remove the jets and spray them, I use a bristle plucked form a wire brush to clean the small orifices in the carb throats and jets, also the small holes in the emulsifier tubes.

If the bike was running good and the problem was a 50 rpm swing at idle, more than likely you had an air leak.

 

[Oldschool1]

Before using carb cleaner, you MUST remove ALL rubber parts. There are o-rings that the pilot screws go through. Make a little wire hook to fish them out. REMOVE the diaphragms. Carb cleaner dissolves rubber. Get all the rubber parts out, remove the floats and spray the heck out of the carb bodies. Remove the jets and spray them, I use a bristle plucked form a wire brush to clean the small orifices in the carb throats and jets, also the small holes in the emulsifier tubes.

If the bike was running good and the problem was a 50 rpm swing at idle, more than likely you had an air leak.

Summarizing the condition and what I've done allready:

1. Bike ran good but that 50 rpm up/down at idle (100rpm total) so in first gear if idling at a crawl in traffic you get the jerk-jerk-jerk. Other than that the bike ran very well. Carbs were very clean in the float bowl.
2. I've removed the hiand a low speed and high speed jets, some very holes not completely clean (minor), and cleaned them by boiling in water and then a soft bristle - they are good now.
3. Removed the pilot screws with spring, washer, and oring.
4. Replaced the rubber carb boots. The boot clamps screws were tightened down all the way against stops, but the clamps were slightly loose like the rubber had thinned out over time. So it could be that there was an airleak at the boots.


Next steps based on above.

I can take the slides out, can remove the float and valve. But there are about 4 or five other orings in the carbs (more?)

If i just spray carb cleaner into and through the pilot screw hole - will that be sufficient? Will it get to other orings / rubber parts? I know there are aluminum pipes with O'rings that connect all carbs for fuel distribution and I DO NOT want to get carb cleaner on those) nor do i want to dissasemble the carb assembly.

Thoughts?

 

[BuddingGeezer]

You should remove the diaphragms. At $100 a peice you really don't want to take the chance on getting carb cleaner on them. I wouldn't dismantle the fuel supply (your getting good fuel). I would just spray the pilot circuit, button the carbs up and go ride. I personally have never used it, but I have heard good things using Pine-Sol cleaner on carbs with no need to remove rubber. Does need time to soak.

 

[RollingJ]

I'm a new guy here, but have been wrenching for a long time.

I won't touch a carb with carb cleaner.

I would use non-chlorinated brake parts cleaner followed by a blast of compressed air if you like your rubber pieces intact.

 

[Oldschool1]

Before using carb cleaner, you MUST remove ALL rubber parts. There are o-rings that the pilot screws go through. Make a little wire hook to fish them out. REMOVE the diaphragms. Carb cleaner dissolves rubber. Get all the rubber parts out, remove the floats and spray the heck out of the carb bodies. Remove the jets and spray them, I use a bristle plucked form a wire brush to clean the small orifices in the carb throats and jets, also the small holes in the emulsifier tubes.

If the bike was running good and the problem was a 50 rpm swing at idle, more than likely you had an air leak.

Update: put the carbs back in with new boots, previously had cleaned all jets out (each hole now flawless) and cleaned the pilot circuit.

Bike idles very stable now (rock solid) from 750 rpm to 1200 rpm) so that seams to have cured the idle hunting (was it a boot leak or slightly cloogged slow jets).

Though at 1800 to 2400rpm, there is a slight cough under no load if increasing thru the rpm range very slowly. This is new. So 1) new boots sealed the air leack(s) and now carbs are out of synch 2) removal, carb work, reinstall affected the carb synch. 3) both 1 and 2 are null hypothesis and it's somthing else (pilot screw adjustment?)

I'll try the synch tomorrow and report back. My guees is it is a synch issue as that apparently is what "fixed" at least the symptom when I first purchased the bike 12 k ago.

Can't wait to do this - need to go for a ride

 

[JPrieST]

Yes, I agree. It is most likely carb sync. Let us know!

Sent from my Nexus 7 using Tapatalk HD

 

[Oldschool1]

Yes, I agree. It is most likely carb sync. Let us know!

Sent from my Nexus 7 using Tapatalk HD

Arrrrgggghhhh - I borrowed my neighbors merc carb sticks and got halfway through the sync when the merc container on the sticks failed and spilled some merc on the garage floor! uhhhh.

Well what is the chance of the merc getting pulled into the intake when the leak occured to atmosphere in the merc sticks? What would be the recourse if some small particles did get in? Given merc has turns to gas at ~630F - would it just evaporate quickly with combustion or other???????


i think i'm done with merc sticks. Should i get vacuum gages or SK sync meter?

 

[JPrieST]

Sorry for the difficulty.

You'll get a bunch of answers to your question, but for ease of use, ease of storage, ease of handling, I vote for the SK. Plus it works!

 

[Mark]

First I will never use Mercury sticks because when I tried to do my 1st carb sync on the ST1100 I read the recommendation that went something like this 'if you do it wrong and pull Mercury into your carbs just ride around the block and it will be blown out through the exhaust'.
I bought a set of carb-tune sticks; but, I have since moved to a flow meter (off brand, not an SK) and can't tell the difference.

Mark