2004 vmax carb problems

[Edward]

...I think Edward's advice is good, though I do rely upon an ultrasonic cleaner where he doesn't favor the use of one....

It's not that don't favor ultrasonic cleaning. As you have laid out your carburetor routine, it is an extremely valuable tool. Ultrasonic cleaners are GREAT. I wish I had one! But jets and internal passages can become so clogged that no amount of soaking will clear them. It takes solvent AND mechanical manipulation.

Whenever I post some mechanical advice on a list, I try to keep in mind, there are others reading the list who are may not be as experienced (as the OP in this case) and my well-intentioned advice may lead them astray.

Brass carburetor jets are just such an example. Sometimes they can be a be a bear to remove and the screwdriver may make a mess of the screwdriver slot. Since this is on the side opposite the engineered opening it has no effect on performance. It hurts my pride but, "no harm, no foul."

However, the size of the opening on the other end can be rendered unusable with the slightest scratch. I use a 7x-45x microscope with a 0.7x-4.5x zoom objective. I wish I could view the spray pattern emanating from a jet while it’s in operation. I imagine it as being a PERFECT cone that’s PERFECTLY symmetric! It must be BEAUTIFUL!

The product a carburetor produces IS beautiful. I know that. It looks like fluffy, white cotton candy. From its physical appearance, it looks as though the “emulsion” could be picked up and held in the hand like a cotton ball.

It's been quite some time since I cleaned these carbs and my memory is admittedly dated but I believe the OP's problem is #37.5 pilot jet in the jet block. It has an almost microscopic opening. ONE strand of a 16 AWG primary wire barely fits through it.

The advantages of using such a small wire is this; it will provide SUFFICIENT mechanical abrasion to work the solvent deeper and deeper into the clog and eventually clear it BUT if pushed too hard it will bend; Aggravating, if one is trying to cut through the clog but virtually fool-proof in preventing damage to the delicate edge at the working end of the jet.
Sometimes I use several strands and spin them in one direction to create what becomes a “poor man’s circular wire brush.”

I became fed up with the off idle tricks my carbs had wherein, I would have to open the throttle an excessive amount to keep the engine from bogging down off-idle and then have the engine’s torque quadruple as the slides leapt in their bores and the carbs began to use the mid-range circuits.

The other problem was that at a steady 20-30 MPH the engine couldn't decide how much horsepower to generate. I had two choices with the throttle; either too much HP or too little HP.

With the mighty VMAX this is a decidedly dangerous behavior. It’s distracting and spoils the joy of riding.
***
One additional thought. I notice that you said you removed the jet blocks and cleaned them.. Did you take the jets OUT Of the jet blocks as part of your cleaning procedure?

 

[sdt354]

What's also helpful to new guys working on their carbs, get a junk carb. and cut it apart.

 

[Fire-medic]

I recently read a story about someone having an emulsion tube which was worn into an oval, ruining the correct operation of the metering the carb slide needle and the emulsion tube have.

I thought, "yes, I see that would cause problems," but frankly, I've never-encountered worn-oval emulsion tubes. I know Factory Pro sells special emulsion tubes for the VMax.
http://www.factorypro.com/Prod_Pages/prody11.html

I suspect that running no air cleaner could accelerate wear to the emulsion tube and to the carb slide needle, over-time.


I would be interested to hear what Sean Morley or 'dannymax' has had in his/their experience(s) of working on these carbs, and how-many needles he/they has/have found worn, or emulsion tubes he/they has/have discovered to be worn.

 

[dannymax]

I recently read a story about someone having an emulsion tube which was worn into an oval, ruining the correct operation of the metering the carb slide needle and the emulsion tube have.

I thought, "yes, I see that would cause problems," but frankly, I've never-encountered worn-oval emulsion tubes. I know Factory Pro sells special emulsion tubes for the VMax.
http://www.factorypro.com/Prod_Pages/prody11.html

I suspect that running no air cleaner could accelerate wear to the emulsion tube and to the carb slide needle, over-time.


I would be interested to hear what Sean Morley or 'dannymax' has had in his/their experience(s) of working on these carbs, and how-many needles he/they has/have found worn, or emulsion tubes he/they has/have discovered to be worn.

Needles should not be rigid, they need some play to 'float' into the E-tube smoothly. A rigid needle can cause out of round-ness. Adjustable needles with the E clip to far from the blunt end or too many shims can place the needle end too close to the plastic retaining screw causing binding. Some grind the plastic threads down to provide relief I prefer placing an o-ring under the screw head leaving the screw in OEM condition.

Seems reasonable to assume hard needles like titanium could accelerate E-tube wear if they were not installed properly also.

Oblong E-tube holes increase the gap between needle & jet throwing fuel metering out of whack.

 

[Fire-medic]

How often have you seen worn emulsion tubes requiring replacement, or worn needles requiring replacement? It sounds logical that without some 'float' or 'give,' that a needle would wear and that the emulsion tube would wear, too.

 

[redster55]

She is alive...............I pulled carbs...soaked the metering blocks in berryman chem dip for about 2 hours each..probed, sprayed, and prayed.. Reassembled everything.. cranked her up and all is well.
Thanks to everyone including dannymax and firemedic for the input and help
J. Nelson Sr.

 

[redster55]

Join the club. I'm also an old mechanic that has never had so much trouble with carbs as these. I've been through them twice now and the only place it seems to run right is full throttle - forget starting and idle. The only thing I failed to do that I know of, is set the float levels, since they looked about right and the new needle valves looked like the old ones. They gotta come off one more time and if I don't get better results it's hammer time!

Hi Oldawg...
I pulled my carbs back off, soaked the metering blocks for at least 2 or 3 hours in berryman chem dip...rinsed in hot water, probed with tiny drill from harbor freight, sprayed carb cleaner through them and plenty of air nozzle application and reassembled and they work fine now. Don't give up.
John

 

[Fire-medic]

Glad you got them functional. Don't forget to synch them, it will help things quite a bit. It's mandatory to do it whenever you split the carb rack.

Removing both of the 'in the tunnel' brass jets, in the jet block is what you need to do to make-sure they clean-up. Remove the main jet, too. And don't forget that small pressed-in brass plug in the jet block also with a tiny orifice. With the jet block stripped, then you soak. Rinse after the recommended time of soaking. Blow them out with a rubber tipped blow gun. "Reassembly is the reverse of disassembly."

From staring-at my idle bike, to having the carbs split-apart and opened-up with the jet blocks and their jets out takes me about an hour. I've gotten quicker.

 

[dannymax]

How often have you seen worn emulsion tubes requiring replacement, or worn needles requiring replacement? It sounds logical that without some 'float' or 'give,' that a needle would wear and that the emulsion tube would wear, too.

You don't see it all that often Philip but when you do it's generally in altered carbs....stg 7, etc. The OEM set up usually works as designed. As with other parts in the fuel system, inactivity can victimize the needles also, left uncleaned old fuel residue will harden affecting the needle float.

 

[Fire-medic]

I've seen what appears to be crystallized, small yellow/white pieces, which I've been told is the alcohol from the fuel which is the 10% formulation they use now, when opening a float bowl.

I'd say that the stock fuel lines are very sturdy, I've had age 25 years lines still working. The one I see most-prone to breaking with age is the 'T' molded fuel line, and it usually tears when you try to wrestle it off. I've tried to save it, by using a dental pick-type tool, lifting the edge of the fuel line, and squirting a bit of WD-40 underneath to make it easier to manipulate the line, when trying to remove it. I keep a spare T gas line on-hand, in-case I have one fail, when tearing-down a set of carbs.

The parts I find needing replacement most-often are the jet block gaskets between the carb body and the jet blocks. I know that usually gaskets are supposed to be installed 'dry,' but I've thought about using some soft-set Permatex as a thin film on the gaskets, to see if it makes them any-easier to remove the jet block without tearing the jet block gasket. Of-course you need to be sure that you don't have any excess entering any passage, jet, or totally-obstructing a passage. What do you think, 'dannymax'? It would just be to allow a better separation of the jet block from the carb body, without tearing the gasket.

 

[caseyjones955]

I was shown to use petroleum jelly on carb gaskets, a thin film, just enough to dampen the gasket material. I did use it with the old Holly, Weber and Dellorto carbs with good success. I did also use it on the jet block gaskets of my Venture, so far so good.

For someone who doesnt have access to pure gasoline it's only a matter if time before it's time to pop the rack and scoop out all the corn squeezings.

 

[Fire-medic]

Yes, I have a small container of Vaseline I use for holding gaskets in-place when I need it. Thanks for mentioning it. I've also used water-soluble gel lubricant.

 

[dannymax]

I install them dry FM going with the theory that they aren't designed to be reused. When initially installed the gasket is compressed by tightening the bolts, it then hardens in that configuration after years of use.

Not saying you can't reuse them but I feel you get a much better seal with new ones. Do I reuse them....no, I don't.

 

[[email protected]]

How often have you seen worn emulsion tubes requiring replacement, or worn needles requiring replacement? It sounds logical that without some 'float' or 'give,' that a needle would wear and that the emulsion tube would wear, too.

One day while riding the CR500 the throttle stuck. Not WFO but, about halfway. I shut it down. Tried again. Same result. Towed it home. Found that the slide was jammed part way open. The hard chrome had flaked off in a few spots and jammed it up. I cleaned it all up, took some fine sandpaper to the slide, and rode it for a few YEARS without issue.

Sold the bike to a friend. Told him to replace the carb, everything else is in good shape. Bought an ATV. Was out riding with said friend plus about 5 others down in Hatfield territory in WV. Luckily, we were riding down the road when the throttle stuck on him. I asked, did you ever replace the carb. His answer was a definite no.

I said, I bet the slide is jacked... He him-hawed around a bit while 6 of us sit there waiting for him do something. There was talk of towing him home (MILES AWAY). I wan't keen on that idea. I said lets take a look. Pulled seat off. Ripped of muffler, mid pipe, sub-frame, and air box all in one piece on side of the "road". Got a clear view of the carb slide and saw a chunk of it was missing! I had to say "Told Ya So" on this one.

Pulled carb off. Looked for pieces of the slide. Didn't really find any of notable size. A couple small chunks where locking up the slide. Further examination showed that the needle was worn down quite a bit. The needle jet wasn't oblong but looked much too big for the needle. Got it all cleaned up. Buttoned it back up and kept riding for the day. The bike didn't run right but, it ran. Got lucky it didn't happen riding on the edge of a mountain which, happens a lot down there.

If you see worn carb parts, replace them ASAP.