Critical Mass Yet Again - ‘90 Gen1

[desert_max]

FM posted his chapter above while I was typing. Let me review what he said here.…

I’m back:

Yes an awfully lot of good discussion on this topic. But I truly think that wire is interfering with the full travel and closure of the needles I have. Terrible design. I will let you know.

 

[Screwloose]

I think I see the problem here gents!

That miserable double hoop wire that Screwloose is talking about. Notice how it affixes to the top of the float needle on my needles. Take a look at the at the photo he uploaded with the calipers. See how the activating wire doesn’t interfere with the travel of the needle? I believe that stupid wire is preventing the needles I have from fully seating. K&L needles don’t have this problem - I’m looking at them now.

They’re pretty darn expensive, but I’m springing for a set right now. I’m tired of messing with this thing.

Surely I am not the only one who has ever encountered this…?

I should have taken a photo of the double wire interfering with the operation of the needle valve, swear to the almighty they interfered. They really did need to be clipped, or better still I should have first tried to swap them over as in F_M method. It was a never ending F&^k-up.

F_M I've worked in engineering all my life and had no idea about the interpolation method for tolerance of a measuring instrument. I like it! I was slightly squashing the rubber at times of measurement and experience told me this was up to 0.1mm Lol.

 

[desert_max]

... slightly squashing the rubber at times of measurement and experience told me this was up to 0.1mm

Just needed to increase the sample size. Poor man's interpolation.

 

[Fire-medic]

In my area of expertise you're dealing in mg and ml, mostly. I cannot recall the first time I was exposed to interpolation, I'm going to guess it was high-school chemistry, the same place that the measurement of the meniscus was taught.

As-to things like ohms, volts, amperes and watts, and multiples of those, I have a very-basic and fundamental knowledge. I can follow "check for this value, or values outside this range" instructions. I'm not above quickly referencing terms and methods to avoid an error, as-in V=I X R and its derivatives. If I need more information, I can ask my wife, she is the E.E. in the family, her 41+ years in the field were how the power is generated, and how it arrives at your home's weatherhead. She is an expert on power generation settings, and on relays. She patiently listens to my questions, and then tells me, "I can give you theory, but the application is on-you." With guidance I can usually arrive at what I need to know. If I have doubts, I defer until I have more data, because as my wife says, "I work with data." She doesn't guess, nor should she.

We're all familiar with the earlier description of the red hair vs the black hair vs the blonde hair, and its site of origin. For my tolerances, a blonde hair is always-good, though in many cases, the painfully-plucked black hair may suffice for an acceptable level of scientific measurement.

 

[Screwloose]

In my area of expertise you're dealing in mg and ml, mostly. I cannot recall the first time I was exposed to interpolation, I'm going to guess it was high-school chemistry, the same place that the measurement of the meniscus was taught.

As-to things like ohms, volts, amperes and watts, and multiples of those, I have a very-basic and fundamental knowledge. I can follow "check for this value, or values outside this range" instructions. I'm not above quickly referencing terms and methods to avoid an error, as-in V=I X R and its derivatives. If I need more information, I can ask my wife, she is the E.E. in the family, her 41+ years in the field were how the power is generated, and how it arrives at your home's weatherhead. She is an expert on power generation settings, and on relays. She patiently listens to my questions, and then tells me, "I can give you theory, but the application is on-you." With guidance I can usually arrive at what I need to know. If I have doubts, I defer until I have more data, because as my wife says, "I work with data." She doesn't guess, nor should she.

We're all familiar with the earlier description of the red hair vs the black hair vs the blonde hair, and its site of origin. For my tolerances, a blonde hair is always-good, though in many cases, the painfully-plucked black hair may suffice for an acceptable level of scientific measurement.

I can refer to the above, it's elec power eng that is my highest education, hence why I've no mates as I take my work too seriously and like to talk shop even in the pub.

If I want a slightly thicker hair that a human's (which is common to be in that situation of decision) I say an elephants ball hair! I estimate it's about two black hairs joined together. I've been using that term for many years now. Although I've never measured an elephants ball hair, you can imagine it being a bit thicker than normal. It kinda works for most situations.

 

[desert_max]

I can die now. In one thread, we've touched on carburetors, interpolation, Ohm's law and elephant pubes. That's gotta be some sort of record, no?

I'm also a lifelong sparky. Test engineer for decades with Lockheed Martin and Abbott Labs, with a boatload of programming associated with it. And data. I "retired" but returned to the workforce. A friend at Intel asked if I wanted to come on board and do some "project" work for him. That was three years ago, and I'm still in the CQN Stress Lab trying to break new designs before they go out the door. Essentially, I work in a data factory. We don't produce anything but information.

Funny thing is, even with an engineering background, I still fly by the seat of my pants in the garage.

So, cheers guys, and here's hoping these K&L needle valves are what I need. If not, I'm parting this thing out.

 

[02GF74]

Also yes, since this carb rack is on the bench, I can hold the needle in the seat with my finger gas still pours through. Both when it first seats and with the button pressed down. They leak like a sieve.

The seats are scrupulously clean. You could eat caviar out of them.

Thats not what i expected. ... but you say there is a wire near the top of the needle valve that limits how far it can go into the seat? In which case, that'll be for sure the cause of the problem.

The original and most after market needle valves I've seen have open wire like this, the float tang fits into the gap, like below

Just remove the wire.
Z1000 float needle valve -show me the wire!!!

 

[desert_max]

...
I am not sure how it is even possible to fit the float tang into that loop when the needle valve is in place.

lol. It definitely takes a bit of finesse. (I use a dental pick to carefully work the "loop" around the tang.)

As to the seat/tip interface: I'd be more apt to suspect an issue with the seat...if it weren't for the fact that I have gas pouring out of multiple vent tubes. And I popped the chambers open on two carbs and can watch with my eyes the behavior. I can't get those two to seal even pressing down with my finger!

And as always, thanks to all for the input.

In fact, I thinks there's enough meat in this discussion that I'll place a link in the "Carburetor" forum to the sections here where we've covered what I believe is some very valuable ground for the collective. (Well, except for the elephant thing).

 

[Fire-medic]

Here is a shot of the K&L needle valve seat. The bottom of the seat appears to have a very-slight taper, not a flat-bottom end-mill finish, the former which I suspect you would find in something machined to a relatively tight tolerance. It does not have a narrower taper duplicating the needle valve viton tip, so there would be more circumferential surface area of the viton tip sealing the orifice. In this aspect the drawing by 02GF74 appears to accurately show the type of seal the viton tip to needle seat possesses (the 'good-one').

The number of the set from K&L is 18-2879 and it's printed right on the envelope, "made in Japan." Assuming that truth in marketing is accepted, and after researching their website, I would say that the K&L stuff is OEM-equivalent, and possibly is OEM, just under their name and not in a Yamaha package.

This is labelled as the 'economy' kit, available for $20 online if you look. It contains what I would consider the essential pieces, no jets/brass, other-than the needle valve and needle valve seat. The jet block gasket is there, usually something which tears upon disassembly. Also the starting enrichment casting gasket (#17, 2006 Yamaha V-MAX 1200 (VMX12V) Carburetor | Ron Ayers ) is there. So-is the O-ring (#10 same fiche) for the CV diaphragm cap, known to run and hide as-soon as the CV diaphragm cap is removed, searching for some unknown space under your workbench to hide from you. The main nozzle (# 34) has a very-skinny O-ring (#33) which is also included (same fiche). The float bowl screw plug (#25) has an O-ring (#26) in the kit. Yes, 'same fiche.' The O-ring (#38) for the needle valve filter net (#37) is also included, it lies below the staked round cover (#39, simply called a 'cap') holding the needle valve seat and the needle valve filter net in-place. There is the O-ring (#40) for the float bowl drain plug (#41) which is just a tapered machine screw by the CV diaphragm caps, that's the one that pees the float bowl contents through the black rubber hoses sticking-through the the carburetor mounting brackets' left and right sides.

The cut gaskets appear to be of a rubberized material, which may be of longer duration than the paper gaskets used upon original assembly, and which may allow careful disassembly and re-use in the future. That bodes well for your next need to clear-out your pilot jets.

Be careful with how you treat and store this stuff, as the CV diaphragm caps, the starting enrichment die-cast body, and the carburetor mounting brackets L and R are no-longer available.

 

[desert_max]

Eureka! (Should have done this yesterday). The benefits of working from home. I just had the bright idea (while working) to walk out to the shop and pull the offending "loop" off one of the original needles. Put that puppy into the seat, turned on the firehose and...

DRY AS A BONE!

Confirmed. Miserable cheap *ssed needles. The loop is definitely interfering with proper closure. I'd be willing to bet this is the reason this motorcycle has been sitting for eight years. Well, that and the photo of the stator connector in post #27 of this saga.

At least now I can be fairly well assured that I'll have this thing going when my K&L needles arrive.

Whew.

 

[Screwloose]

Here is a shot of the K&L needle valve seat. The bottom of the seat appears to have a very-slight taper, not a flat-bottom end-mill finish, the former which I suspect you would find in something machined to a relatively tight tolerance. It does not have a narrower taper duplicating the needle valve viton tip, so there would be more circumferential surface area of the viton tip sealing the orifice. In this aspect the drawing by 02GF74 appears to accurately show the type of seal the viton tip to needle seat possesses (the 'good-one').

The number of the set from K&L is 18-2879 and it's printed right on the envelope, "made in Japan." Assuming that truth in marketing is accepted, and after researching their website, I would say that the K&L stuff is OEM-equivalent, and possibly is OEM, just under their name and not in a Yamaha package.

This is labelled as the 'economy' kit, available for $20 online if you look. It contains what I would consider the essential pieces, no jets/brass, other-than the needle valve and needle valve seat. The jet block gasket is there, usually something which tears upon disassembly. Also the starting enrichment casting gasket (#17, 2006 Yamaha V-MAX 1200 (VMX12V) Carburetor | Ron Ayers ) is there. So-is the O-ring (#10 same fiche) for the CV diaphragm cap, known to run and hide as-soon as the CV diaphragm cap is removed, searching for some unknown space under your workbench to hide from you. The main nozzle (# 34) has a very-skinny O-ring (#33) which is also included (same fiche). The float bowl screw plug (#25) has an O-ring (#26) in the kit. Yes, 'same fiche.' The O-ring (#38) for the needle valve filter net (#37) is also included, it lies below the staked round cover (#39, simply called a 'cap') holding the needle valve seat and the needle valve filter net in-place. There is the O-ring (#40) for the float bowl drain plug (#41) which is just a tapered machine screw by the CV diaphragm caps, that's the one that pees the float bowl contents through the black rubber hoses sticking-through the the carburetor mounting brackets' left and right sides.

The cut gaskets appear to be of a rubberized material, which may be of longer duration than the paper gaskets used upon original assembly, and which may allow careful disassembly and re-use in the future. That bodes well for your next need to clear-out your pilot jets.

Be careful with how you treat and store this stuff, as the CV diaphragm caps, the starting enrichment die-cast body, and the carburetor mounting brackets L and R are no-longer available.

The original seats I removed had this small taper that partially mates to the viton needle tip. I do not know if the aftermarket ones I fitted had this taper also, damn I should have checked as this may be my problem.

Not sure I’m reading the above correctly (my fault) but two mating tapers are generally not the same angle to ensure they do not stick together due to suction of the two surfaces. under use they would squeeze together and mate under pressure with the rubber side falling into shape of the solid surface side. But would want to pull apart naturally due to the intended taper mismatch, hence never stick. You may be saying that, it is just my experience of mating tapers when one side mates and breaks continuously.

 

[Screwloose]

Eureka! (Should have done this yesterday). The benefits of working from home. I just had the bright idea (while working) to walk out to the shop and pull the offending "loop" off one of the original needles. Put that puppy into the seat, turned on the firehose and...

DRY AS A BONE!

Confirmed. Miserable cheap *ssed needles. The loop is definitely interfering with proper closure. I'd be willing to bet this is the reason this motorcycle has been sitting for eight years. Well, that and the photo of the stator connector in post #27 of this saga.

At least now I can be fairly well assured that I'll have this thing going when my K&L needles arrive.

Whew.

Well done, wish I had posted this problem last year. At the time I even contacted the supplier and said to them what the hell is going on when I need to cut one wire off the valve, they said they have sold many of them over years and never heard of it. Thought then it was just me and maybe they did not need clipped, but could not get around the fact the wires were interfering with the needles working properly.

Cheers I feel a bit better about that now. Maybe we have discovered something very important.

 

[Fire-medic]

Eureka! (Should have done this yesterday). The benefits of working from home. I just had the bright idea (while working) to walk out to the shop and pull the offending "loop" off one of the original needles. Put that puppy into the seat, turned on the firehose and...

DRY AS A BONE!

Confirmed. Miserable cheap *ssed needles. The loop is definitely interfering with proper closure. I'd be willing to bet this is the reason this motorcycle has been sitting for eight years. Well, that and the photo of the stator connector in post #27 of this saga.

At least now I can be fairly well assured that I'll have this thing going when my K&L needles arrive.

Whew.

I'll give you $750 for that devil-bike, as-is!

 

[Screwloose]

I'll give you $750 for that devil-bike, as-is!

D_M previously did say he likes to buy up failed projects.

Now you will have several hundred bikes out there just waiting to be scooped up for pennies, all with aftermarket s&^t needle valves. I think $750 is fair considering the amount of bikes you will now accumulate in your workshop. I'll have one too please.

 

[02GF74]

Eureka! (Should have done this yesterday). The benefits of working from home. I just had the bright idea (while working) to walk out to the shop and pull the offending "loop" off one of the original needles.

Err, I said that last night. I am not entirely sure what the purpose of the wire is other than to guarantee the needle valve can never drop out but when I took mine apart that couldn't happen away. Many carb models don't have any wire on the needle valve.

 

[desert_max]

Err, I said that last night. I am not entirely sure what the purpose of the wire is other than to guarantee the needle valve can never drop out but when I took mine apart that couldn't happen away. Many carb models don't have any wire on the needle valve.

Yeah, I know you did, but it didn't dawn on me until just now that you were recommending to "run" them that way. Although I have needles on order, I guess that might just work! Dang. If so, could've saved a few quid.

 

[desert_max]

...and thinking about this a bit more, I think the wire does serve a purpose. Goes back to something Screwloose was saying about stiction between the rubber tip and the camfered (or not) seat. If the needle were to "stick" on the seat, in theory the wire would allow the float to pull it off. Otherwise, once stuck, it's stuck.

(I guess better to be stuck closed than open, but either scenario means pulling the carbs).

 

[desert_max]

FYI:

From Randakk's archives:

" Just to be safe, no matter what combination of float seat / float pin parts you use, you need to make one more check. There should be nominal clearance between the outer “shoulder” of the float seat and the pin valve spring “clip” when the rubber tip is resting on the bottom of the seat with no pressure other than gravity. The “clip” is the wire retainer that surrounds the float “tang.” Make this check with the carbs upside down on your bench. I don’t actually measure this, I just eyeball to make sure there is some visual clearance. A bit of clearance is good…no clearance is very bad!

If the aftermarket float pin is too short and / or the aftermarket float valve seat is too thick, the “clip” will bottom on seat shoulder before the rubber tip can do its job of controlling the fuel flow. I make this visual check on all carbs I re-do. I’ve never found a problem of this nature with OEM parts but you never know when there might be a packaging mix up or the like. "

Now he tells me.

 

[Fire-medic]

He uses different terminology.

'Float seat' = Yamaha needle valve (seat)

'Float pin'= Yamaha needle valve

'Pin valve spring clip'= Yamaha needle valve (clip) which is shaped like an upside-down U while many aftermarket pieces are upside-down L shaped (cantilever)

aftermarket float pin is too short= needle valve LOA is shorter than OEM

aftermarket float valve seat is too thick= I suppose this means, the aftermarket needle valve seat is too-tall. 'Thick' I expect to mean diameter, which I do-not believe he meant here.

 

[Screwloose]

FYI:

From Randakk's archives:

" Just to be safe, no matter what combination of float seat / float pin parts you use, you need to make one more check. There should be nominal clearance between the outer “shoulder” of the float seat and the pin valve spring “clip” when the rubber tip is resting on the bottom of the seat with no pressure other than gravity. The “clip” is the wire retainer that surrounds the float “tang.” Make this check with the carbs upside down on your bench. I don’t actually measure this, I just eyeball to make sure there is some visual clearance. A bit of clearance is good…no clearance is very bad!

If the aftermarket float pin is too short and / or the aftermarket float valve seat is too thick, the “clip” will bottom on seat shoulder before the rubber tip can do its job of controlling the fuel flow. I make this visual check on all carbs I re-do. I’ve never found a problem of this nature with OEM parts but you never know when there might be a packaging mix up or the like. "

Now he tells me.

Yeah; what a plonker.

I think it all comes down we both had the same problem where on assembly fuel was pouring out the overflow(s), but I just never immediately thought what happened to me last year would be relevant to you, so i’m also a plonker for holding back so long about the clip. I spent at least two hours staring at these carbs to find that problem. That was my fifth in/out attempt with the carbs and was on the verge of admitting myself to a mental institution.

Its a classic case of a gap slightly bigger than a human hair allows fuel to pass, I.E. an elephants ____ hair to be more precise.

I just could not remember the word stiction yesterday. Cheers mate.

I really do think this problem was brought to light by the many discussions going back and forth, some relevant and some not, but the not so relevant ones kept it all going and the thinking continued. This is the only forum i’ve stuck for more than a week, and I really did enjoy seeing D_M getting a solution out of it all, not to mention some great free education flying around.