Carb flooding new member help

[mack]

David

The 80 carbs have plastic/foam floats. The height from the bowl gasket surface (without the gasket) is 23mm. This should give you a gas level of about 3mm down from the lowest edge of the side flanges of the carb body or roughly even with the bottom of the washer on the bolt holding the bowls in place.The margin for error of that fuel level is +/- 1mm giving you a green zone of 2-4 mm from the lowest edge of the carb body. When you encroach over that 2mm level, fuel will first come out of the starter jet, if you allow the fuel to go higher it will then come out of the air jet, higher again and it will actually run out the barrel and drip off the bell. I've never seen fuel come out of the vent holes higher up. The fuel level would have to be impossibly high for that to happen.
I found that 23mm is arbitrary and just because time is spent making sure the float hieght is exactly 23mm never means that the fuel levels will be identical or with in the designers intended range. To ensure the fuel is in the "green" zone, they should be checked with clear hoses statically before you mount them on the bike. That way if a couple are out of whack, you can adjust the floats to bring the fuel to the correct level.
The reasons for the variance are poor quality control in manufacture of both the floats and some needles spring tension at the little plungers. These are typically made in tiawan, china, etc. where volume is more important than quality. If Japan was still making them, this would not be an issue at all.

[motoman]

Well I certainly was not going to raise them from the 23 they were sat at. In my search for what could possibly be causing this issue I have read everything I could find on the web. My Clymer 78-81 says float lever should be 25.7 mm. I have seen seen recommendations from 23 to 27 so Motoman I don't think following suggestions on this would indicate that my knowledge is "in question". I certainly don't know everything especially when it comes to this animal but I'm no rube. And you assume I did not follow advice to clean the carbs and changed many things one at a time. Like i've said ad nosium I must have had these things off 40 times now. I'm actually getting pretty good at it. I can have them off in 5min now and about the same going the other way. Mack Thanks for the offer but I could not do that (to much pride I gues). But thanks anyway.

As far as float adjustment, you might have a look at pages 254 of your Clymers before jumping to conclusions. BTW, the Clymers main jetting chart IS incorrect for the 80-81 Specials. The 5GL16 metering rod carbs use 110's across all four. As far as actual RUNNING fuel levels, anything BELOW 4mm, it'll barely run right, and when it DOES get fuel, it's all at once,think the water glass full, or half full and blowing across the top of a straw, watch what happens as you have to blow across straw harder(venturi velocity) to pull the water from half full glass as opposed to full glass. It'll pull up the straw half full glass, but when it does come out the top it's all at once and harder to control a constant flow. ALL carbs work the same way, downdraft, sidedraft, or updraft....sicle or auto.et running DECENT, but not perfect by any stretch of the imagination. A static setting in 99.9% of the time will NOT leave actual RUNNING levels the same on all four carbs. Reason being, you have a mechanical fuction going on that keeps this from happening. Namely, the spring loaded float needle springs ALL not having the same compression load rating(quality control the K&L's lack...in the worst way). And yes, that DOES matter when bike is running. That compression difference DOES come into affect, period, and I have proved that to myself also.
Nothing I've stated here that I haven't proved to myself. 40+times off with the carbies......sheeeeh, ain't nothin' to how many times I 've had mine off testing different scenarios over the past 5yrs. FWIW, I can also tell you 1mm of static float change IS 3mm of actual fuel level change. Ain't a whole lot of volume for fuel with the floats in there. To get levels precise, your 'widdleing' it down to 10-15thousands for a final exactness. Exactness is critical, starting with fuel levels FIRST, or mixture adjustments/sync are a moot point, and your just fooling yourself if you think the motor is getting the SAME dose of fuel to each cyl. Sure, one can set idle mixtures to somewhat compensate, but then your comprimising the vacuum sync setting. So, now you see how things just sno-ball, STARTING with RUNNING fuel levels not being identical across all four carbs.
Definitely the 'fold' here can be of help,but my above explanation can't be any plainer and more to the point.
Remember to, that that STATIC setting is just a 'ballpark' to get motor up and running reasonably good, but not perfect.
Correct fuel level settings, all the way to the final tune, these particular inline fours are bare none, the silky smoothest inline fours ever built, period.
Quality went into the whole crank assembly unsurpassed my ANY other of the Jap manufacturers, to the point that some 25yrs. later, mother Yamaha unofficially said they wished they never had built that kinda durability into the XS/XJ11.....and never have since. Hope that helps with a little insight as to what your dealing with, and how to overcome it.

[motoman]

Sorry for runnin' that all together without paragraph seperation, but I was on a roll and just decided to lay it all out there for ya' in one 'bite'.

[mack]

general

Motoman: David is frustrated right now and I know your passionate about these carbs, but lets not snow him under with the fine details right now. Lets stop the leak first, set the levels to the green zone second, then we can regale him with the intricate details of tuning. However since he has worked with other style carbs before, I believe the tuning aspect will be second nature to him.
Dave: Your making progress, you've identified that the #2 carb is the one leaking; and, it's leaking from one or all of the holes in the bell. This is indicative of excessive fuel. Only two reasons for that. Either the float levels are too high OR the fuel valve assembly isn't doing it's job in shutting off the supply.
So, you've said you played with multiple float settings and the proplem still exists so we can rule out the float height. Now that leaves us with the fuel inlet valve assembly. It only has two components that can contribute to a leak. The seat or the needle.
Seat: there are four styles of pressed in fuel seats, they all look the same unless you get out a set of calipers and measure them. Mikuni make a slightly shorter seat with a larger diameter inlet hole and is easily identified with the little square in a corner of a larger square stamped into the bottom. The others are made by K&L. One is slightly taller than the mikuni and the last one is much taller.the only thing you'll find on a K&L is the number 2.0 stamped into the base. In general, the seats will fail for two reasons. Either the small o ring is worn and brittle or the tapered needle seat inside has an imperfection. This could be due to dirt, varnish or a scar. You've said you cleaned and polished yours so we can rule out dirt and varnish. That leaves the scar in the taper or the O ring. Now these o rings need to be supple to seal properly. Just because they look good doesn't mean they are. if you can't take a tooth pick and slide it under the o ring and see some elastisity it's time to change it. The scar aspect is more difficult because you would need a very good magnification to actually detect one. But gas being fluid will always find it.
Needles: you'll find that the needles come in all sorts of shapes and sizes and Some are shorter some are viton tipped and some are metal, some have wide deep flutes and others are made of aluminum and have small vertical ribs at the corners. They fail at one end or the other. Usually the sharp tip will have wear marks in it, viton has hardened or at the other end the spring plunger is seized or weak.The bad news is that you have to have the right needle for the seat you have. Most people buy the seat and needle assembly together to avoid this problem. However, some people are more frugal minded and will buy the needles separately off ebay etc. This is usually where issues occur, with one exception. if you have the genuine mikuni seats any needle will work!And the float tangs will compensate for the length difference.
I know it's frustrating but keep at Dave, your getting there. Trust me you've almost got this licked and you'd always regret a hasty descion of "selling it cheep"

[cdavidscee]

Musical chairs

Mack thanks for the response. i have already changed the o-ring on the seat. The most frustrating thing is that it's not just find the carb that'a flooding as they seem to take turns?. And once in a will one (as in the last time) one will stick closed. I have identified which carb was flooding many times only to take it apart (along with the rest) and find nothing wrong? Each time before I put them back on the bike I do the static test with the clear hoses. Last time with a 23mm set the levels were just below the bowl lip on all four no flooding during the static test. Put em back on the bike let it sit with fuel on for a while no flooding. Take it for a ride starts running **** stop look down fuel running on the ground (again). Pull the drain plugs no fuel in #3. Pull the plugs: one white (no fuel) one black (flooding) two other nice coco brown. I'll pull em again today and see which seats are in em. Any idea why these carbs are so problematic. I have raced a mini sprint modified with 85hp (dyno) CRX 250 running alcohol. Had to pull off after each race and spray em down with WD 40 to cut down on the corrosion:confused from the alcohal. Never had a problem with em. But they had brass floats and steel needles. Have you ever had trouble with float interference with the bowls?

[cdavidscee]

Mack's pix

Was looking at your pix Mack you have an amazing shop and looks like you could eat off everything. Unbelievable resto work. Ya compared to your level I am a rube, Ha Ha

[mack]

dave

check your PM's

[cdavidscee]

Once more into the fray

I received and installed new Mikuni needle and seats = same thing. I have taken the bike to a shop who said he will give it a shoot no guarentees? He said he was going to replace the floats, seats (again) and complete rebuild kit (again) $600. We'll see how much luck he has maybe it's just my bad JU JU. Hoping to get a ride in with my duaghter before the end of summer ( that's why I bought it in the first place).

[mack]

not sure

What to say. I've offered you a set of 80 midnights that i've tested and dialed in for the cost of shipping. But your going to pay some boozo $600 who makes no guarantee. Live and learn Dave. I'm not offended, just can't figure where your head spacing is at.

[motoman]

What to say. I've offered you a set of 80 midnights that i've tested and dialed in for the cost of shipping. But your going to pay some boozo $600 who makes no guarantee. Live and learn Dave. I'm not offended, just can't figure where your head spacing is at.

+1.......

[CaptonZap]

What to say. I've offered you a set of 80 midnights that i've tested and dialed in for the cost of shipping. But your going to pay some boozo $600 who makes no guarantee. Live and learn Dave. I'm not offended, just can't figure where your head spacing is at.

Hey Mack, you should have told him you would sell him yours with no guaranty for $600, and give him a core allowance of $50.
Another $100 allowance for R&R by a local shop, and you might have made the sale.
Some people have more money than brains.
I just never get to do business with them.

CZ

[Bonz]

So, you wouldn't take Mack's offer because of "Pride I guess" or something similar, but will pay $600 for a shop that has a thimble full of experience relative to this forum?

[Prisoner6]

... I have taken the bike to a shop who said he will give it a shoot no guarentees? He said he was going to replace the floats, seats (again) and complete rebuild kit (again) $600.

(Don't know) What to say. I've offered you a set of 80 midnights that i've tested and dialed in for the cost of shipping. But your going to pay some boozo $600 who makes no guarantee. Live and learn Dave. I'm not offended, just can't figure where your head spacing is at.

Dave,

I've been on this Forum going on 2 yrs. now (Not very long, I know).

But from what I've learned of Mack and his carb knowledge and abilities, you would be doing yourself a huge favor by sending him your carbs.

We're all here to help each other, and your carbs could not be in better hands than Mack's.

You say you've already taken the bike to a shop ... if they haven't starting working on it, it's not too late to reconsider your strategy and send Mack those carbs.

[madmax-im]

I received and installed new Mikuni needle and seats = same thing. I have taken the bike to a shop who said he will give it a shoot no guarentees? He said he was going to replace the floats, seats (again) and complete rebuild kit (again) $600. We'll see how much luck he has maybe it's just my bad JU JU. Hoping to get a ride in with my duaghter before the end of summer ( that's why I bought it in the first place).

you have got to be effing kidding me otherwise you're prolly the dullest knife in the drawer...

[TopCatGr58]

Let's play nice guys!

Hey guys,

Okay, he tried multiple times, failed, and got frustrated. Came here for some help or ideas. Yes, Mack was most gracious in his offer, but it's Dave's choice to do what works for him, and utilizing a local fellow "feels" right, or is simpler/easier than packing up the carbs and sending them across country!?

Let's hope the "fellow" is able to get them right....provided he gets the proper parts and not the generic faulty K&L kits! At least Dave's learned that about what to use and do vs. what he has already tried.

Hopefully we haven't chased him away with all of the browbeatings!
Then again, if he gets it working right, he may not need to come back anyways...but at least another Xsive will have his Nose Hairs in the wind...
don't want him running around without a helmet!

T.C.