Two-faced symptoms

[MisterCinders]

Yes. Fresh O-rings in there. They dripped like this before, even though the prior o-rings were pretty fresh. Since some other jet o-rings had gotten mangled, I went ahead an grabbed another set from Bwringer and freshened up all the rubber in there.

[BigD_83]

Are you sure it is a drip from the drain screws and not gasket leaks working their way down? Is it from ALL drain screws?

[MisterCinders]

I'll check. Think it's only some of the drains. I don't see fuel on the bowls.

[MisterCinders]

Whiskey
Tango
Foxtrot

This float situation just gets worse and worse.

I pulled the carbs several times this weekend to try and get the float settings right. No matter what I do, the carbs now flood with gas.

Definitely need to change the oil and filter now, as gas may have entered the crank case. Won't start the bike again until I do that.

Meanwhile, I am trying to get the floats sorted, as I cannot change the oil/filter every damn time I test start the bike. After several adjustments, each time I run fuel into the carbs (not running the engine), they spew fuel out of the drain hoses and pods.

The float needles/seats are clean and clear. No gunk, no scoring, etc. I have spares and have tried swapping some out, but the results don't change.

I have tried setting the float heights at different levels. Recall that I had set them too high by caliper (so too low when running) at about 27mm and got lean idling. Then I dropped/raised them to 22-23mm and she idled much better. Now, however, she floods gas.

Specifically, with the carbs installed, vacuum line plugged and remote tank with long fuel line and petcock on PRIME, the bowls fill and within seconds, they overflow into the drain lines and pods. It literally vomits fuel everywhere.

I have changed the float levels to increase them by caliper (so reducing the actual float level) with no changes. They are at about 26mm now. Without even running the engine (because of the oil/gas problem), the bowls fill and start flooding within < 30 seconds on Prime.

BTW - I did check the petcock. It doesn't flow in the ON position unless vacuum is applied. Plus, these results happen with vacuum plugged and petcock on PRIME, so I don't think it is a petcock issue.

I understand that a bad needle and seat will fail to close and allow flooding, but why would most, if not all, of my needles fail at once?

No fuel is coming through the vacuum line (it's not even connected for this). Is there any other potential fuel source/passage that could be overcoming the float system? Maybe the choke circuit is not closing? The seat o-rings are in place and seem to be solid.

My floats/needles are OEM and don't show and crud or ridges. The spares I have for swapping are The springs feel OK, at least not stuck. Is there any particular amount of spring resistance to look for? What else should I check in that inspection?

A few of my spares are those shiny but crappy replacement parts from some rebuild kits. I actually tried a couple of those, only because my OEM spares were jumbled up in the box, so I could not precisely match a needle to its original seat. The kit sets were still in their bags as matched pairs. Yes, those parts are crappy as compared to OEM, but would every one of them fail straight out of the box? Is there any method to matching up seats and needles from the jumble of spares?

I really don't want to drop $125 on four new OEM float needle sets. Any tips on how to test the ones I have to isolate the overflow problem. In other words, how might I check that the float needle valve cuts off fuel flow when closed, which would indicate that something else is causing the flooding?

If the valve is actually closing and there is no other source of fuel into the bowls, the only other culprit I can think of would be the floats. But the floats themselves also look solid. No mangled rubber, and they move easily on the pins. I can drop them into a small bowl of fuel to make sure they actually float, but otherwise I am stumped. Maybe they are catching on some part of the bowl when I close them up? Knocking the bowls with a screw driver does not stop the overflow.

Finally, the caliper measures the float as it rests on the needle. Is there any alternative measurement to account for spring pressure (e.g., measuring the height with spring compressed)? Provided the springs are functioning and not sticking, would that measurement even matter?

[MisterCinders]

OK - float height setting recommendations are all over the place, for the same measurement?!?

The specs for the caliper method of setting the float -- i.e., carb upside down, distance from the gasket mating surface (no gasket) to the top of the float bob as it just touches the needle.

Service Manual says 25mm - 27mm

Carb Spec Sheet on BassCliff's site says 23mm +/- 1.0mm (22mm - 24mm)

Clymers says 23mm - 25mm

Mikuni Tuning Guide says 15mm - 17mm

What the hell?

[MisterCinders]

OK - ordered some parts to revisit this fuel flooding issue. These include, new oil filters (to change the gas/oil now and have some back ups), new needle seat o-rings, and some new valve needles from Z1.

After searching more forum posts, I think the plan of action will be to

a. "blow test" the float needle assemblies to see if they close;

b. drop the floats into some petrol to confirm they float and do so evenly;

c. massage the floats back to even level and plumb to make sure they aren't crooked or catching on something within the bowls;

d. replace the seat o-rings and needles with new parts for best sealing and even spring loads;

e. set the floats at the higher end of specs (about 25mm as best I can tell);

e. put the rack on a stand to test the valve seals and float levels with my drain/tube level tool;

f. even if there is no gassy smell in the oil, change the oil and filter to flush out any gas/oil mixture; and

g. be awesome.

[BigD_83]

Do you think the Mikuni Guide might be a typo? That is so wildly different than the other manuals

However, I checked in on a KZ forums, and one link to a photos with your carbs definitely shows 17mm being measured...

I also read about one case where the floats were hanging up on a bit of excess gasket sticking into the float bowl

[MisterCinders]

Do you think the Mikuni Guide might be a typo? That is so wildly different than the other manuals

However, I checked in on a KZ forums, and one link to a photos with your carbs definitely shows 17mm being measured...

I also read about one case where the floats were hanging up on a bit of excess gasket sticking into the float bowl

I included some new bowl gaskets in that order. Not sure if they are hanging up the floats, but having to go in and out of the bowls so many times, I just know I am going to tear one of the gaskets at some point.

Now that back ups are on the way, of course, my current gaskets will last forever.

[paco13]

Did you ever solve the rust in tank problem you mentioned in th OP?

Also, I check my needle and seats with a vacuum pump (mighty vac). Carbs inverted with just the weight of the floats on needles hook vac line to fuel inlet, see if holds vacuum. If not you can usually hear where the leak originates. Use drops of fluid in different locations 'til you find the source when it seals, slows the vac leak.

[MisterCinders]

The rust has not been an issue for awhile. Still need to do full clean on that tank, but the fuel flows clear with no rust or sediment.

[keman]

Forgive me if I missed it in the thread, but have you replaced the manifold orings between the intake tubes (after carbs) and the head? Those buggers can cause a world of bizarre symptoms when they leak.

Setting the screws for highest idle... The only way I could hear it was by starting 1 turn out, turning 1/4, wait a few seconds and listen. .. turn another 1/4 and wait a few seconds. .. repeat. .. on my bike, it took almost two seconds for it to change. Once I got a noticeable change, I back it off 1/8th and listen. .. no change, you're done with that one. If it changes, go back out 1/8th and call it done.

[MisterCinders]

Replacing the intake o-rings and those ****ty chalk screws with some SS Allen heads was one of the first things I did when I got the bike.

Blow tests on the float needles came back good. BigD may be onto something though. The bowl gaskets seem to jut into the bowl a bit, and they contact the floats. I will carefully trim those back and see if that frees up the float movement. If that fails (or, more likely, if I botch the trimming and mangle a gasket), hopefully the replacement gaskets are a better fit in the bowl.

I also pulled the floats themselves to straighten them out. They weren't too bad in shape. But when I reset the heights this time, I will reverse my process. Instead of setting the height and then evening the floats, I'll get them as close to parallel first at whatever height and then set the height with the tab.

Maybe that slow and steady approach to highest idle will break my impasse on that test. Once the oil is changed and the carbs aren't barfing gas, I'll try the turn and wait method to see if that gets results on those air screws.

[MisterCinders]

Update for posterity - still waiting on the oil filter, so I have not started the bike.

I messed with the float settings for ages though. Best I can tell, the bowl gaskets were too close to the floats in places and causing them to stick. I took an xacto knike to them and carefully shaved them back about 1mm to give more clearance.

Although I have not tested them on a running engine yet, static fluid checks show fuel sitting at the right level. They also stopped puking gas out of the overflows when I feed them petrol.

Fun tip: a handy thing to use for these "wet" tests is a metal tray that you use for paint rollers. I put the tray on the bench and then used a couple of wood blocks to stand the carb rack up. The bowls can drain (or flood) into the tray. The gas is not worth recycling except maybe to clean some parts, but its contained so you aren't splashing accelerant all over the garage.

[BigD_83]

Glad to hear that you are now pointed in the (Let's hope) right direction. Little things like that are quite frustrating when you know that everything else points to all being okay.

[MisterCinders]

Great, now I've come full circle.

Changed the oil and filter. Changed the gaskets and needles to eliminate the flooding problem. Set the floats at about 23.5 mm and did a static float test to confirm (i.e., using the drain plug tool, but not on a running bike).

Everything looks good, though one of the bowls still drips a bit at the drain screw. I am chalking that up to the bowl itself, since the float level shows up below the gasket line.

When I put the bike back together, I am back to fluctuating and hanging idles. Lean symptoms. Plugs are still pretty sooty. Another oddity, the bike struggles to start at first without some choke and tries to die when you close the choke. But . . . wait for it . . ., that hesitance vanishes if you blip the throttle. Thereafter, it idles without choke no problem except for hanging and wandering. The sputtering struggle to start is only at the very beginning and always disappears after it warms up for a minute if I do a little throttle blip. It's like the revs clear up the blockage or something.

Yes, my valves are good. I just checked them a week or two ago. All were still in very healthy spec clearances from last year's adjustment.

For the next go around, I have cleaned and will refresh my pods, in case that fuel flooding through them screwed things up.

I haven't found any air-leaks that might cause this, but to make sure I also double checked my intake boots and o-rings. My o-rings are new as of last year, and they looked fine. The boots are soft enough and have no cracks, etc. The o-rings were fine. I let the rings soak in some petrol for a half-hour or so to freshen them up, and then cleaned the boots and intake surfaces to put her back together.

As for jetting, my latest set up is:

Fuel screw - 1 1/8 turn out
Air screw - 1.5 turns out
Pilots - 17.5
Needle - 4th slot
Mains - 122.5
Float levels about 23.5 mm

Before this tear down, I had a slight richness problem with 15 pilots, fuel screws 7/8 - 1 turn out and air screws 2-3 turns out. Now I cannot get the idle to behave?!? I am loath to bring the floats down more, since the flooding problems. The flooding might just have been a sticky float issue, but I don't want to push the envelope there. Plus the level test looks good on the floats.

Will try again tonight with freshened and lightly oiled pods (they needed to air dry overnight).