Way off fuel screw settings?

(1977 KZ1000LTD, new carb holders, airbox ducts and filter installed. All stock intake and exhaust, stock jetting in carbs. Carbs absolutely spotless clean. Good voltage to coils.)

I set the fuel screws on my carbs today using the highest idle method in the book.

Book initial settings are 1 turn out, my settings ended up being....

#1 = 1/4 turn
#2 = 1-3/4 turns
#3 = 3 turns
#4 = 1-1/2 turns

This is the third time I have set the screws with similar settings. I would think they are wrong but I keep ending up with almost the same settings. It seems to be happy with these settings.

When I bought the bike some PO had bottomed out the screws so hard that #1 screw tip broke and was stuck in the carb,the other 3 tips were deformed. I replaced the screws with new ones from Z1E.

Number three cylinder bothers me. It's exhaust pipe stays MUCH cooler than the others. It is also the only carb I can bottom out the screw without causing the motor to die. After getting its mix screw to 3 turns out its pipe warmed up and is seems to be running better. But it's pipe still seems to stay cooler than the others.

There was a pop pop coming from the right side exhaust until getting the #3 screw past about 2 turns out.

It's (#3 cylinder) exhaust valve clearance is the only one out of spec...(shim installed)....

#1 Intake .08 (2.70) Exhaust .15 (2.45)
#2 Intake .11 (2.55) Exhaust .15 (2.65)
#3 Intake .08 (2.65) Exhaust .17 (2.65)
#4 Intake .08 (2.60) Exhaust .13 (2.65)

I don't know if that would cause this.

I have never vacuum synched the carbs, just bench synched. Maybe I really need to get them synched up? Could that be part of the problem. Or maybe its due to the PO goofing up the fuel screw holes in the carb so the settings are going to be very different than stock?

Tomorrow I will take a look at the plugs after letting it idle a few minutes. If they read ok should I worry about this? Bike seems to run great. It will even idle @ just 500 RPM when warmed up!

Have you set the actually wet fuel level with the Clear Tube Test?
Even though you have new manifold boots, have you checked for vacuum leaks?
When you say the carbs are spotless, did you soak them in a cleaner or a ultra-sonic cleaner? Then use compressed air to blow through all passages and jets? Are you sure the jets match, not just #'s but either new jets or checked for size in case someone drilled them?

Motor Head wrote: Have you set the actually wet fuel level with the Clear Tube Test?
Even though you have new manifold boots, have you checked for vacuum leaks?
When you say the carbs are spotless, did you soak them in a cleaner or a ultra-sonic cleaner? Then use compressed air to blow through all passages and jets? Are you sure the jets match, not just #'s but either new jets or checked for size in case someone drilled them?

Yes to all of the above.

I'm going to take it for a quick ride tomorrow morning then let it idle for a few minutes in the driveway before shutting it off. After letting it cool down I'll check the plugs. That should give me a good indication of whats going on at idle. I'll report back with the results.

Due to your opening statement "new carb holders, airbox ducts and filter installed. All stock intake and exhaust, stock jetting in carbs. Carbs absolutely spotless clean. Good voltage to coils." I wouldn't screw around with those carbs again just quite yet....

You stated fuel screws and I'm thinking pilots/slow jets, are we speaking the same or do I have this all backwards.....

As for number of turns on the pilots, hell they never match identical even on brand new carbs for too many other variables come into play.... Same time, 3 turns versus 1-2 turns is excessive no doubt and should be checked into....

The over compensation in turns of #3 pilot could easily be due to miss Sync adjustments. Same with the under compensation of turns for #1 @ .25 turns.

Need to SYNC or you'll be chasing this all over the place....
You'll be surprised how little a change in the Sync adjustment effects the other circuits in the carbs, doesn't take much....

Yes, OMR, pilot screws is what I'm on about. I have VM26SS carbs, the screws are on the bottom, engine side of the carbs. Out for rich, in for lean.

So, from your advice, until I get them synched I will not know for sure if the wacky mix screw settings are a problem. Good.

I was expecting the #1 carb to have a setting like that. (.25 turn) When I was ordering mix screws from Z1E I told them that the PO had broken the tip of the #1 screw off in the carb. He told me to expect that the correct setting may just be barely cracked open due to the hole being messed up. So that doesn't surprise me....but #3 with 3 turns does.

I'll get them synched and go from there. I need to get something to synch with first....should I go with gauges or a manometer?

www.z1enterprises.com/ItemDetails.aspx?i...nizer&item=MP08-0411

www.z1enterprises.com/ItemDetails.aspx?i...nder&item=EM84-68594

Defently get the Morgan carb tune ....... got mine off their web site in England took only six days. No fluid to evaporate, bubbles and is made to last. Many others here like it too.

Here are the plugs after running at idle for about 10 minutes. Yes, I have a big @$$ fan blowing on the engine during driveway running.

Left to right, cylinders 1-4. #1 looks way rich, with only 1/4 turn on screw. #2 looks great, golden brown. #3 looks rich but not quite as bad as #1. #4 looks slightly lean....but just barely.

Again, this is with mix screws set...

#1 = 1/4 turn
#2 = 1-3/4 turns
#3 = 3 turns
#4 = 1-1/2 turns

I'm going to set #1 to 1/8 turn open, #3 to 2.5 and #4 to 1-3/4 and run it again and see what they look like.

If you benched synced the slide height, i can't see it being so far off as to cause that #1 plug soot. 2 things come to mind, one being that you said the hole for the pilot screw was damaged, Just how much would be the question. Can you see a mark on the tip of the screw where it contacts the seat inside the bore of that pilot hole? Maybe use a sharpie felt tip marker as cheap bluing and see where that screw contacts compared to #2 which looks good.
And the other is that it is rich from the carb adjustments/ jetting. Either the fuel height it still to high, or the pilot jet is damaged/ loose, or the slow speed air jet is plugged/ damaged.
Oh a third thing, which if any do you have the vacuum line to the petcock hooked up to? If it leaks through the diaphragm it will add fuel to the cylinder through the vacuum line.

Yup...#1 being so far off doesn't surprise me. When I got the bike the tip of the screw was broke off and stuck in the carb! When I told the guy over the phone at Z1E that, (while ordering new screws) he said that he had seen that before a few times and that on those carbs the mix screw needed to be just cracked open to run correctly. Kinda sucks but not much I can do about it.

I could put some dykem on there and see...but...what could I do about it anyways? The way I look at it, if it runs correctly with the screw open 1/8 turn, then so be it. Right? Other than getting another set of carbs and hoping bubba didn't screw them up too?

I have checked and rechecked the fuel height with the carbs sitting level on the bench. I haven't checked it with them on the bike. Guess that's next.

But, I really do think I need to vacuum synch them first and then see. Like OMR said, or I could be chasing my tail around. I did bench synch them, but I have had them apart a few times since then. I did not touch the slide height adjusting nut/bolt but still, they have been apart. So don't rely too much on the bench synch being perfect at this point. Until I get them vacuum synched I'm not going to worry too much, just wanted to post the pic because I said I would.

All jets are bran new from Z1E. No vacuum line on the '77 1000LTD. The bike seems to idle very well right now. I can't be too far off based on how it runs. Cruising down the road is great, bike pulls hard too, no problem with take off from a stop. Other than the plug readings and wacky mix screw settings I would say its perfect.

The dye test is also to see if for some reason there might be spring bind on that screw. Which would keep the tip from seating, then it may be open father than 1/4 turn. Just a thought.

Motor Head wrote: The dye test is also to see if for some reason there might be spring bind on that screw. Which would keep the tip from seating, then it may be open father than 1/4 turn. Just a thought.

I could see that. I remember that last time I had the carbs off the bike I screwed all 4 mix screws in until they seated and then looked at the tips to see how far they came thru into the carb throat. They all looked even, but that was just by eyeball.

I'll try the dykem on #1 and #2 and see how they look. Then make slight adjustments to the screws, run the bike again, and see how the plugs read.