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How to remove a stuck pilot jet with a broken screwdriver slot

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Fire-medic

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One of the vexing problems our bikes are prone-to, is a blocked, obstructed, plugged pilot jet in the jet block. It's enough of a chore to get to the pilot jet, because the carbs have to come-off, split into at-least two, pairs, and then the float bowls have to come-off. SOmetimes I can wiggle the four float bowls off, sometimes I need to loosen the screws which hold the pairs together:

For the pair with the idle screw adjuster

the chrome bracket the float bowl vent tubes stick-through (and which holds the idle thumb screw)

the bracket which holds the throttle cable in-place (the one closest-to the 3-way gas inlet)

On the other pair of carbs, it's the rectangular bracket holding the carbs together, and the chrome bracket the float bowl vent tubes stick-through.

Because I was tearing-down these carbs for an immersion in the ultrasonic tank, I wanted to completley-remove the rubber gas lines.

On an old bike, and let's face it, the newest of the Gen 1 bikes is 13 years-old, you can easily-destroy the brittle gas lines by ham-fisted handling of them during the disassembly. I suggest that you consider replacing the gas lines on your bike if you're this-far into a carburetor tear-down. It's possible that you may never have to replace them again. Have you seen pics or videos, or an in-person event where a motorcycle's gas line hose ruptures, dumps fuel onto a hot exhaust pile and now the bike is a total-loss? Replace the hoses.

If you're really-cheap, you can use straight gas line tubing and a suitable T-fitting to replace that one unique molded-T gas line our bikes use. I'd just as-soon replace the brittle, old gas line with the OEM Yamaha part, they're nice and supple unlike that brittle, crusty, hard and inflexible hose on your twenty year-old ride. (or older!) Here it is:

Item #65
Hose-gas line T

26H-14987-00-00
$30.47


Here's where you can justify the cost of that Yamaha OEM molded-T gas line: replace the other gas line, for the other pair of carbs, with a piece of 1/4" gas line. The shops sell it by the foot, and buying a foot, will save you probably $20, as the Yamaha OEM straight piece of gas line is $$21.68. NAPA sells reinforced rubber hose, 1/4" I.D. for $1.49/foot; one foot is all you need. See? You just saved $20! Put that $20 towards the cost of the OEM Yamaha molded T-hose, and now that molded T-hose is only $10.47! In other words, $32 gets you an OEM Yamaha molded T-hose and a one foot length of NAPA 1/4" I.D. reinforced rubber hose. Get a couple of clamps of whatever type you prefer. I like the spring steel ones instead of the serrated stainless-steel hose clamps. If you buy the former, just be-sure to buy the ones sized to the proper O.D. of the gas line you buy.

Hose-gas line (this is the OEM Yamaha straight piece of hose. No-need to buy this when you can buy a piece at NAPA 1/4" I.D. for $1.49. Fiche is same as above.

Item #64
31H-14987-00-00
$21.68

Be very-careful with your jet blocks! These are discontinued from Yamaha!

There are a few things you should have on-hand to do this repair. Order the following:

Item #42
Jet, pilot
Size: (37.5)

4G0-14142-37-00 (discontinued #)
4G0-14142-37-A0 (current #)
$6.10 Buy four of them if you plan to keep your bike, they are somewhat easy to bugger the screwdriver slot (remember the purpose of this thread, eh?)

Item #35
Gasket, jet block
3JB-14199-00-00
$9.41 Buy four of them, as these often tear when disassembling the carburetors.

Item #43
Cap (for pilot jet hole, this is the small round rubber plug which fits into the pilot jet/jet block hole once the pilot jet is installed)
22V-14968-00-00
$6.10 I suggest buying at-least two, buy four if you're keeping the bike, replace them all.

Item #44
Pipe, main bleed (this is the middle hole/jet on the jet block, it too gets a rubber plug-below)
26H-1414G-00-00
$12.65 I suggest buying at-least two, buy four if you're keeping the bike, replace them all.

Item #45
Cap (for main bleed pipe hole, this is the small round rubber plug which fits into the main bleed pipe/jet block hole once the main bleed pipe is installed)
22U-14968-00-00
$6.18 I suggest buying at-least two, buy four if you're keeping the bike, replace them all.

Note that the rubber caps for the pilot jet and the main bleed pipe holes are different sizes.

end, Part I
 
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Fire-medic

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The guys who are the professional mechanics will agree with me, it's better to replace the parts with OEM new ones, than to count on re-using the jets, the rubber plugs, and the jet block gaskets. Yes, if you're exceedingly-careful, you might be able to remove the jet block without tearing the gasket underneath. However, if you replace it, you have a newly-gasketed surface and should get many years of use out of it. The rubber plugs often become deteriorated after decades in a gasoline bath; they harden, they fall-apart when you're trying to remove them, and they play 'hide-and-seek' when you drop one under your workspace, never to be seen again. Spend the few bucks, you'll be glad you did.

Item #36
Needle valve assembly
1FK-14190-15-00
$16.40 Replace all four. This is what keeps your gas where it should be and where it shouldn't be.

Disclosure: I have used K&L needle valve assemblies, they are cheaper than OEM. However, I've said, "Use OEM," so that's the part # and price I included here. I normally don't replace the needle valve seat, if your bike has 40,000+ miles on it, you might want to consider replacing the neelde valve and seat together. There is a kit including the cap for after you press-out the old seat, and insert the new one.


Item #10
O-Ring
93210-03119-00
$4.78 Buy a couple, like the rubber plugs for the jet block holes, these have the habit of playing 'hide-and-seek' with you. These are the tiny O-rings under the Constant-Velocity (CV) Caps, easily-lost if you don't-know to look-for them and to save them. IF you're not tearing-down your carburetors to tank them, like I'm doing, you don't have to remove the CV caps and you won't lose them. However, for the minimal price of these, you'll have a replacement when yours run-away from you. Same carburetor fiche link.

Item #22
Pilot screw set
12R-14105-00-00
$6.51 These are the screws under the CV carburetor caps. It's a good idea to have a couple of these around should you need them, as a prior bike owner may-have buggered yours, and that's why he sold it to you so-cheap, because he never fixed it, and it runs like-it. "It just-needs a set of plugs, man!" Same carburetor fiche link.

OK, back-to the carburetor jet block. Let's say that you've managed to remove the four float bowls. Did you have a tough time trying to get the float bowl cover past the float bowl vent pipes? That's whay I gave some input about having to loosen the brackets holding the carbs in two pairs, so you could remove the rubber gas lines, and replace 'em. You do not have to break the carbs down into for separate units! You just have to give yourself enough wiggle-room to get the float bowls off. Then you can remove the jet blocks.

About removing the jet blocks: they're held by two phillips screws. Remove the screws. Before you try to remove the jet blocks, grab your trusty mechanic's pick, the one that looks like what the cute dental hygenist uses on you during your semi-annual teeth cleanings. Dentures? 'Never-mind!'

Us the mechanic's pick to carefully separate the gasket from the carb body. I usually try to leave the gasket attached to the carb jet block. Work the edge of the pick entirely-around the jet block gasket, below it actually, with the pick tip resting on the carb body. You can see the gasket nearly the whole way around the jet block, and as you use the pick, you should feel the jet block release its bond to the carb body and the gasket. If the jet block detaches from the gasket, carefully-remove the jet block. Be sure that you aren't pulling up on the jet block, with one-half of the gasket stuck to the jet block, and one-half stuck to the carb body. You want to try and save the gaskets.

If the jet block gaskets tear or delaminate, that's why you've bought four new ones. Clean the surfaces, use the new gaskets. On the re-assembly use the new gaskets and save the old gaskets for spares if you were successful in removing the old jet block gaskets, intact.

OK, now we have the jet block on the workbench and you were successful in removing the main bleed pipes. Maybe you were successful in removing two of the pilot jets, but when you tried the third and fourth, you felt the screwdriver slip, and when you turned upside-down the jet block and tapped it on the workbench, all you were able to see were gold slivers from a fragmented pilot jet. No pilot jet came-out! Now, you did use some type of carb cleaner solvent, before trying to unscrew all-four, yes?

OK, so only two came-out. Spray more carburetor cleaner into those holes, let 'em soak. Go to your local hardware store or Amazon, or Harbor Freight Left Hand Drill Bit Set, 13 Pc. $(8.49) and buy a set of left-hand twist drills. Regular drills have a right-hand twist, you're buying a set which turns in the direction that unscrews a screw, as you're drilling.

Carefully align the drill bit in the hole. I used a 9/64" drill bit. Be sure that you have your cordless drill set to -Reverse- and slowly pull the trigger. You don't need to bear-down with a lot of force, the jet is brass. Brass is soft. The bit should start to grab and drill. Use a slower drill speed, and less-force than if you were trying to drill a hole in steel plate. You should feel the bit working, and if you have a sensitive touch, you may-feel that suddenly the resistance of the drill working is much-easier. Stop drilling. Remove the drill. Invert the jet block, and tap it on the workbench, and you'll likely see the pilot jet and some shavings fall-out of the jet block. Your left-hand drill unscrewed the pilot jet as it was drilling the brass, and your problems are over. Use solvent and compressed air to blow-out the passgaeways. Use your new jets and new gaskets if you're keeping the bike.

You can also use this method on the pilot screw, the one under the bottom of the CV cap.

end, Part IIVMax pilot jet drill-out.01.jpgVMax pilot jet drill-out.02.jpg
 
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Julian Tomkins

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that's good information, I haven't had to take my carbs apart yet other than to do the 'shotgun' procedure,
has any body tried heating the carbs before dismantling to see if it makes things easier, like in a similar way you can heat engine cases to remove/fit bearings
 

Fire-medic

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that's good information, I haven't had to take my carbs apart yet other than to do the 'shotgun' procedure,
has any body tried heating the carbs before dismantling to see if it makes things easier, like in a similar way you can heat engine cases to remove/fit bearings
In my experience, it's isn't necessary. Sean or dannymax can confirm. I suggest replacing your screws with hex head bolts or allen screws. They're easier to use. Don't forget to use a straight-jaw Vise-Grip on your security screws for the CV caps. Or, go to Harbor Freight and buy one of their sets of security screw tips.
Security Bit Set with Case, 100 Pc. ($10)

Security Bit Set, 33 Pc. ($6.79)

It doesn't get much-cheaper than those sets.

A good pair of 10" Vise Grips has saved the day on numerous occasions, on all-sorts of projects. Another tool well-worth having is a Dremel rotary tool. I find those particularly useful for slotting the phillips screw heads on your master cylinder caps, after you destroy the 'X' trying to break the corrosion loose. A small abrasive reinforced disc I find to be safer than the thin ones, which aren't reinforced, and can easily shatter with any side pressure. Wear your eye protection!
 

Julian Tomkins

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my carbs have had all the exterior bolts replaced with stainless allen heads, I just wondered if pilot jets might release easier with heat as I've read quite a few have had problems getting them out
 

Fire-medic

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my carbs have had all the exterior bolts replaced with stainless allen heads, I just wondered if pilot jets might release easier with heat as I've read quite a few have had problems getting them out
A solvent soak should help to release them. Heat is not recommended by me around carbs! Ever-seen a melted carb? A heat gun might be a different thing, but any name-brand carburetor cleaner spray should help your jet removal. Wear eye protection!

I'd try a 3/16 inch screwdriver, carefully inserted and rotated until it was in the pilot jet slot, and then a few light taps on the end of the screwdriver handle. If you're gonna use a hammer, make it a small, light one! I'd probably use a 3/8" ratchet handle, and, "tap, tap, tap." You want to introduce some vibration into there, so the solvent you already sprayed into the jet block hole can penetrate better.

If your efforts result in the screwdriver slipping, and golden shards (but no pilot jet :mad:) on your workbench when you upend the jet block, and dump-out the contents from your pilot jet extrication attempts, see posts #1 & 2.
 

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