Carbs d@#m pos!!

[Ken Talbot]

No upper "T's" going to air filter from carbs

Simple question - are there two "T" fittings between carb#1 and carb#2, and between carb#3 and #4 i.e. an upper fitting and a lower fitting between each pair. Never mind all the other stuff for now about what is connected to what.

How many "Ts" are there?

Answer that definitively and we can proceed fom there.

[XS1100_OEM4ME]

Thanks

1st, thanks to all who have helped me here. 2nd, yes. I have two sets of "T", one set, the set marked "A" in Phil's pic is vented to the OEM air box and both are clear to carbs (I will check to make sure they are clear through the air box. The set marked "B" is fuel inlets and is clear to the needles (I ordered the 920V needles and seats, should be here tomorrow, will install with thin metal washers to aid clearance) I have tested all 4 brass floats under hot water with no leaks, new bowl gaskets with clearance for floats checked and will be set at 25.7 mm and Max. depth set keep from binding the needles (thanks Phill for this one). I cleaned everything and found some junk in one of the emlusion tubes, I installed all the "factory" jets, main needles (set to the midlde setting) I have a clean tank with good petcock OEM screens, the 920V's have new screens. I have disasembled the gas cap and cleaned the check valve inside, the fuel lines are all good and clamped correctly, the octy has been cleaned and re-built and works fine with good vacume supply from one intake manifold, the ing advance will be hooked to the other small vacume supply on the carb body (is this correct, or backwards) I have set all valve clearance to factory spec. I am considering adding two inline fuel filters between the bowls and both fuel feeds (Prime / ON, is this a good idea The timming is correct and I will sync all 4 carbs with a PRO set of vacume gauges AFTER I change the oil / filter again from the last fuel dump into the cyl's. Am I missing anything this time Thanks again for understanding my Oh yea, and I quit drinking

[cywelchjr]

Try leaving the vent lines unhooked and see if that makes a difference. It might be that the blockage is at the airbox.

[crazy steve]

IIRC, didn't your bike have pods on it installed by the PO when you got it? If that was case, and you picked up a 'new' airbox, remember that the '80-81 boxes have the carb vent hose nipples molded into them, but they're not drilled. If using a late airbox/early carbs, you have to drill those out....

[XS1100_OEM4ME]

Quick Carb question!

Ok, putting everything back togather and don't know where the small hole on the bottem of diaphragm vacuum piston is suposed to point tward Air box or tward the motor The rubber diaphragm has an allinment tab but the piston can be rotated before install, 360deg. Thanks

[XS1100_OEM4ME]

Nope

IIRC, didn't your bike have pods on it installed by the PO when you got it? If that was case, and you picked up a 'new' airbox, remember that the '80-81 boxes have the carb vent hose nipples molded into them, but they're not drilled. If using a late airbox/early carbs, you have to drill those out....

Nope, everything on my bike is original (except the new XV920 needles +tires / batt and other ware out items) Thanks

[bikerphil]

Pretty sure it faces the motor.

[crazy steve]

Yep, Phil's got it....

[XS1100_OEM4ME]

Leaking carbs from hell!

Here are a couple more picks, I did install the idle screws and set at 1 1/2 turns before install:

[bikerphil]

From looking at those pics, looks like the throttle cable bracket and the octy bracket are on incorrectly. Octy should be in front in between carbs 1 & 2 and throttle cable stay at front between 2 & 3. Carbs look awesome.

[TopCatGr58]

Well as Adam on Mythbusters says,

There's Your Problem"

Okay, the second photo clearly shows that you have the earlier model carbs, only 3 ports on the inlet bells, but when you look at your first photo of the carbs from the engine side, it appears that you are missing some screws!

You should have 4 Pilot jet screws sticking out of the top of those towers right on the top center of the carb throat in front of the choke/enrichener rod! The 3 screws between the carbs are for adjusting the butterfly openings.

I don't think the later model pilot jet screws can fit down into the older pilot jet towers? So..without the pilot jet screws, or at least the proper ones, they probably won't work right or at all!

T.C.

Here's a set of 79SF carbs I cleaned up a few years ago, note the large screws on the top of those towers, these are the Pilot (Idle) Screws that you set to 1.5 turns out. The 3 large screws between the carbs are the SYNCHRONIZATION setting screws, you adjust them first to get the butterflies opening to the same amount while on the bench=bench synch, then you use the vacuum gauges to fine tune them with teh engine running.

[petejw]

Ok, putting everything back togather and don't know where the small hole on the bottem of diaphragm vacuum piston is suposed to point tward Air box or tward the motor The rubber diaphragm has an allinment tab but the piston can be rotated before install, 360deg. Thanks

if those rubber diaphrams can be rotated on the slide they need to be replaced they shouldnt be able to move.

[XS1100_OEM4ME]

Yes to both

Yes, I did rotat the top brackets before install, just was paying to much attn, to diaphragm seat 1st time. Also, as I mentioned in the post, I installed all 4 fuel mix screws and set at 1 1/2 turns out before install. Tonights bench test with air pressure from my mouth showed a slight leak in R/S outboar carb, took apart and poloshed float shaft and both float towers on the insides of them, re-tested, no leak. Also, when I installed on the bike earler today, I was using a 1 gal. gas can converted to a field test tank ( it is much easer to sync carbs with the stock tank out of the way) and I held it over my head as I couldn't see gas flowing through clear filters at first, could this have caused too much presure for the needles to hold back the fuel, even if they were working correctly

[bikerphil]

I was using a 1 gal. gas can converted to a field test tank ( it is much easer to sync carbs with the stock tank out of the way) and I held it over my head as I couldn't see gas flowing through clear filters at first, could this have caused too much presure for the needles to hold back the fuel, even if they were working correctly

I doubt it would be too much pressure but you never know. I hope everything works out this time. Good luck!