Howto: Replace your stuck carb drain screws

This writeup is intended for Hitachi carbs.

1) Order a set of replacement carb drain screws. I got my set from ArizonaSteve for $13. Turnaround was very quick, and I had them in about a week.***Edited by SnoSheriff***



2) Pick up a set of Craftsman Drill-out Micro Power Extractors. I was able to get a set from the store for $29.99. Or you can pick them up online here.



3) Open up your new screw extractors and take a few minutes to read the instructions included ( They are hidden under the cardboard picture in the box ). Doing so will help make this whole process a lot easier. Make sure you have a Variable Speed, Reversible drill available. Every part of the screw extractor process takes place in reverse, and often times at very low speeds, with lots of pressure and torque.



4) I started out by pulling the carbs off of the bike, and covering the intakes, to prevent metal shavings from getting into places they shouldn't be. I also found it easiest to extract the screws with the bowls still attached to the carbs. This way you are able to keep hold of the whole setup, instead of having to clamp the individual bowls down separately. I also did the 2 outside carbs first, then removed those bowls, covered their innards, and did the inside 2 carbs.



5) Find your 1st offending screw



6) With the drill portion of the "M6 & 1/4" bit, begin the extraction process as outlined in the instructions. ( Remember to keep it in reverse! )



7) Your new hole should be centered and straight if all went well.



8) Now flip the bit around and extract that screw!





9) The freshly extracted screw should look something like this:



10) Repeat the process 3 more times ( unless you were able to get any out with a screwdriver that is! )



11) Use an air hose to clear the holes of any debris or corrosion that may have build up over the years. Be sure to cover the other hole with your finger. Do this both ways ( so you clear each passageway thoroughly ) Then run some carb cleaner through there and repeat the air cleaning.



12) Install your new Carb drain screws ( with a little anti-sieze or similar ) and your ready to set those floats!



The whole process start to finish took me about an hour. It was really pretty easy. Setting the floats to all be within spec, well, thats a different story.

 

Cool guide.

Would be good to copy into the FAQ section.

 

I've never use those drill out extractors but I do have to say I'm sold on them now!
I'll have to get me a set next time I'm by a Sears

Thanks for the GREAT illistration!

 

I agree! This is an excellent post. So great, I copy and pasted it onto my computer to keep. Thanks dude. You rock!

 

Seeing as how we have lots of power tools and a grunch of Irwin bolt extractors at my job, I ended up using those instead. For a drain screw that didn't wanna let go, that screw came out pretty damn easy once I had the extractor tapped into the hole...

Now to order me some replacement screws.

 

Dito, what they said.

 

Nice guide.

One suggestion though:

Go ahead and remove bowls. Screw bowl to scrap of 2X4. Clamp 2X4 in vice. Go to town.

 

Got a set of screws from Steve as well for the XJ but sold it before they came. Did the Virago's off the carb between 2x's in a vise as well. If you don't, you need to remove the bowl anyway to make sure you didn't blow any debris into the bowl that would get clogged in the jets.

 

Where do I get my screws at I have emailed steve with no reply. There has got to be a way to find these online somewhere.

 

Check with Chacal
He has lot of carb parts

 

Well, yes I do. In stock, too!. The HCP54 style is the allen-headed, stainless steel version.

Carb Bowl Drain Screws:

e5) OEM Hitachi carb Bowl Drain Screw. Cad-plated alloy steel phillips head, taper-point screw fits into the drain hole passage of each carb bowl. Made by the original Yamaha supplier.

HCP864 OEM phillips-head cad-plated alloy-steel carb bowl drain screw, each:
$ 14.00

HCP864SET4 OEM phillips-head alloy-steel carb bowl drain screw, set of 4:
$ 49.00 set


e6) Aftermarket Hitachi carb Bowl Drain Screw. Natural finish alloy steel phillips head, taper-point screw fits into the drain hole passage of each carb bowl. Just like the original Yamaha screw but without the bright cad plating.

HCP3113 aftermarket phillips-head alloy-steel carb bowl drain screw, each:
$ 5.00

HCP3113SET4 aftermarket phillips-head alloy-steel carb bowl drain screw, set of 4:
$ 18.00 set

f5) Aftermarket Hitachi carb Bowl Drain Screw. Bright finish 18-8 stainless steel phillips head, taper-point screw fits into the drain hole passage of each carb bowl. Just like the original Yamaha screw but made of stainless steel.

HCP3112 aftermarket phillips-head stainless-steel carb bowl drain screw, each:
$ 6.00

HCP3112SET4 aftermarket phillips-head stainless-steel carb bowl drain screw, set of 4:
$ 20.00


g5) Aftermarket Hitachi carb Bowl Drain Screw. Bright finish 18-8 stainless steel allen head, taper-point screw fits into the drain hole passage of each carb bowl. Works better than the original Yamaha screw; not only is made of stainless steel, but the larger allen-head design allows for more torque to be applied to the screw, forever ending the stripped/stuck/ruined drain screw problem that has plagued Yamaha owners forever!

HCP54 aftermarket allen-head stainless-steel carb bowl drain screw, each:
$ 5.00

HCP54SET4 aftermarket allen-head stainless-steel carb bowl drain screw, set of 4:
$ 16.00


http://www.xjbikes.com/Forums/viewtopic ... rt=45.html

 

BTW, while you have your bowls off, I can't stress how STRONGLY I recommedn that you take the time to inspect, and clean out your starter jet passage down in the bowl. This is one of the tiniest passages within the entire carb, and as you can imagine, clogs easily. Almost EVERY bowl that I see has a partially or fully plugged starter jet.

Clogged starter jets will make not only starting very hard, but idle and off-idle performance is affected by this circuit, also.

And how do you clean it? With a tiny, Tiny, TINY drill bit and some compressed air or brake/carb cleaner:


z7) Aftermarket wire gauge Drill Bit for Bowl Starter Jet Cleaning. As you will quickly discover if you ever try to clean or rebuild your Hitachi carbs, the tiny, non-removable starter jet that is stuck wa-a-a-y down at the bottom of a drilled passage in the carb bowl is next to impossible to clean. For one, did we mention that the jet opening is TINY? And did I also mention that it's stuck way down at the bottom of a small passageway, and basically unreachable? AND THEREFORE, NO ONE EVER REALLY EVEN ATTEMPTS TO CLEAN IT OUT? And that a clogged starter jet not only means trouble starting and idling, but that starter circuit is actually also involved in idle and off-idle performance?

Well, how do you actually clean it? Even the tiniest cleaning rod in our HCP950 and HCP953 carb passage cleaning sets (above) aren't small enough to fit through this starter jet (it is THE smallest jet-passage in the entire carb)...

Well, here's how you clean it: with this tiny drill bit. Just big enough to get through the jet, but not big enough to ENLARGE the jet (that's a huge no-no), this high-speed steel bit can be gently rotated (but never "pushed", as it will break) through the toughest of crud. This is the only way to properly clean these starter jets.

NOTE: this is a TINY drill bit, and will not chuck into a standard drill chuck. You have to use a mini pin-vise attachment or do it carefully by hand...... ALSO: this drill bit is a mere 1-1/2" long, and as such, will disappear below the top "plane" of the bowl as it goes down into the jet. You will have to use a pair of very slim needle-nose pliers to grip the tip of this drill bit and rotate it!

HCP2296 Starter Jet Clean-Out Drill Bit
$ 11.95

P.S. how do you know when your starter jet is really, truly, zestfully clean? One of two ways:

a) shine a strong penlight or mini flashlight into the bottom of the bowl, where this jet passage "intake" is located. Look through the top of the bowl down into the jet passage "outflow" passage (this is the passage that the brass suction tube in the bottom of the carb body actually fits down into). Focus your eye carefully on the jet opening and make sure it's clean. P.S. it helps to do all this while in a darkened area....

b) put the spray tip (you may have to gently shape the end of it to a fine point) of a can of carb or brake cleaner into the intake opening of the starter jet and let rip a spray. A STEADY, FINE, POWERFUL STREAM OF FLUID WILL COME OUT OF THE OUTFLOW PASSAGE ON THE TOP OF THE CARB BOWL IF THE JET IS PERFECTLY CLEAN AND OPEN. I mean this stream will absolutely spit out a good 5-10 feet. If the stream isn't powerful and laser-like precise coming out of the jet, then the jet isn't zestfully clean.....

BTW, when using the spray-stream method of checking the jet, don't even THINK of putting your eye or face anywhere even NEAR the jet outflow path, unless you like a painful and potentially serious trip to the emergency room.


Here's a good image of what a CLEAN starter jet looks like:

http://www.xjbikes.com/Forums/viewtopic ... rt=15.html

 

Something relating to my fuel line is blocked up, and I have been told to 'clean the carbs'. I figured I'd start with the 'easy' route... Went to the shop and talked to a few guys there, they recommended "yamaha carbeurator cleaner dip". I was told to disconnect the fuel lines, drain the carbs, and pour it in and let it sit overnight. Sounded easy enough. Wouldn't have to take the carbs off...

So I disconnected the fuel lines, took off the gas tank so I could better see what I was looking at. Once I found out which ones the 'drain screws' were, noticed they were incredibly stripped....

So I started reading this post.

Do I have to take the carbs off to get the drain screws out? Should I try another method first like seafoam or carb cleaner to add to the gas tank? Any suggestions...

 

There's no easy shortcut to "cleaning the carbs." They are not really that hard to pull out and once you do, you'll want to disassemble them and clean them spotless. You're never going to get any kind of performance or stability out of seafoam or any other "magic fix" like you will from cleaning them by hand.

As for the carb drain screws, you're not going to get them out without pulling the carbs off the bike. If you attempt, you're gonna damage them beyond being able to remove them.

 

So this is how the drain screws look, fully installed & inserted. Has anyone had any problems with the screws working thier way out?

 

I've had mine in since the day I wrote this and have had no problems. I have also ridden it pretty much everyday since.

 

Cool, I was about to start looking for replacment screws for mine. Seeing this thread now was perfect timing.

 

I already got the screws in the mail, thanks Len, they look great! So for less then half the price of OEM I get better screws (hex head!). I would say I can't wait to put them in but I still have to drill out the old ones .

 

This is a gret post, exactly one of the jobs I have to do this winter on my new/old 650 (picked it up this summer for 250.00$). Does anyone in Canada know where I can buy these screw extractors.

Thanks

Ken
Montreal

 

Has anyone found a replacement ss allen-type drain screw for the Mikunis?

 

OK, on a related note... has anyone had to tap and helicoil a fubar'd float bowl drain screw extraction? I have several damaged heads on the OEM drain screws of my Mikunis. And with the seeming nonexistence of stouter aftermarket stainless, allen head type drain screws for the Mikunis... I was kicking around the idea of tap & helicoil to accept the aftermarket Hitachi drain screws. Too risky? More trouble than it's worth? Comments?

 

Heli-Coils are BOMBPROOF. BUT if you screw it up you are buying a bowl.
Loctite has a product called Form-A-Thread that works really well ( about like J-B Weld ) with a release agent and if you screw up it can be drilled out ( Heli-Coils are a real #@%^(&%# to drill out ).
TECHLINETOM

 

Used this process on my 81 XJ650. Only had to extract 2 drain screw. Removed the bowls and clamped them in a vise with a scrap piece of plywood on each side so I would not damage the bowls. Extracted 2 of them worked great!
Got new screws from Chacal. Worked like a champ!

Also those craftsman extractors are da bomb!

 

I'm needing some Drain Screws for my 81 Maxim xj550h i managed to get them out with a bit of cursing and elbow grease "thanks for the Writeup!" Now where do i go to order these HCP54SET4?? i bent a float while getting the diaphram screws out with the float bowls off "DOH" now am really gonna have to set the float levels now. If someone would E-Mail me at RPC227@yahoo.com would love to get some screws rebuild kits.

Ohh yeah i can't find the post about the Hoppe's Gun solvent #9 again but WOW that worked well to cleanup the jets, Emultion tubes and idle needles.

 

I'm needing some Drain Screws for my 81 Maxim xj550h i managed to get them out with a bit of cursing and elbow grease "thanks for the Writeup!" Now where do i go to order these HCP54SET4?? i bent a float while getting the diaphram screws out with the float bowls off "DOH" now am really gonna have to set the float levels now. If someone would E-Mail me at RPC227@yahoo.com would love to get some screws rebuild kits.

Ohh yeah i can't find the post about the Hoppe's Gun solvent #9 again but WOW that worked well to cleanup the jets, Emultion tubes and idle needles.

 

Send a PM to chacal. That's his part number.

 

Here are all of the different versions of the MIKUNI bowl drain screws that I carry in stock. They are different from the Hitachi bowl drain screws (which is the HCP54 part number!):


OEM Mikuni bowl drain screws:


HCP865 OEM Mikuni carb bowl Drain Screw, correct bright plated, alloy steel, panhead phillips drive drain screw features the machined land just below the head for the acceptance of the HCP4400 o-ring listed below. This style drain screw is used on all XJ550, XJ650 Turbo, XJ900, and XJ1100 models, although it will also fit all XJ700-X and XJ750-X models also. Each:
$ 6.00

HCP865SET4 OEM Mikuni carb bowl Drain Screw, correct bright plated, alloy steel, panhead phillips drive drain screw features the machined land just below the head for the acceptance of the HCP4400 o-ring listed below, set of 4:
$ 22.00

HCP4400 OEM Mikuni carb bowl drain screw O-RING, for the HCP865 drain screw listed above. Each:
$ 2.00

HCP4400SET4 OEM Mikuni carb bowl drain screw O-RING, for the HCP865 drain screw listed above, set of 4:
$ 7.50



HCP4399 OEM Mikuni carb bowl Drain Screw, correct bright plated, alloy steel, panhead phillips drive drain screw. This style drain screw does NOT use an o-ring and is correct for all XJ700-X and XJ750-X models, but can also be used successfully on all XJ550, XJ650 Turbo, XJ900, and XJ1100 models, each:
$ 6.20

HCP4399SET4 OEM Mikuni carb bowl Drain Screw, correct bright plated, alloy steel, panhead phillips drive drain screw. This style drain screw does NOT use an o-ring and is correct for all XJ700-X and XJ750-X models, but can also be used successfully on all XJ550, XJ650 Turbo, XJ900, and XJ1100 models , set of 4:
$ 23.00



HCP6279 aftermarket Mikuni carb bowl Drain Screw, using a socket head cap screw (allen-head) design, and made from an 18-8 stainless-steel material. The large hex-drive design ends the "frozen-stuck-stripped: bowl drain screw problem forever. NOTE: the design of this screw results in the large, round allen head sticking out approximately 1/2" from the carb bowl body. Each:
$ 7.50

HCP6279SET4 aftermarket Mikuni socket head cap screw (allen-head) stainless-steel carb bowl Drain Screw, set of 4:
$ 24.00


All this and more at:

http://www.xjbikes.com/Forums/viewtopic ... t=180.html

 

I was able to get three of the four drain screws out of my Hitachis with a butane pencil torch and and a hand impact driver tool. (Lisle LIS29200 Hand Impact Driver Tool SKU LIS29200). The number #2 Phillips head that comes with the tool is a perfect fit. I soaked it with PB Blaster, put the bowl in a vise between two blocks of wood, heated the area around the screw, and smote the tool with my hammer.

The fourth drain screw was too badly boogered to get it out with the impact tool, so I bought a new cobalt 1/16 drill bit, chucked it into my dremel tool, and carefully cut a new flathead groove into the end of the screw. Then I narrowed a size 8-10 flathead screw bit (by grinding off the outside edges) to fit my newly created groove. I put the 1/4 inch screw bit into my 1/4 inch socket, put the 1/4 inch socket onto a 1/4 inch to 3/8 inch adapter, and fit the female end of the 3/8 inch adapter onto the impact tool. I put the heat to it, fitted the modified 8-10 screw bit into the groove, and smote it several times until it broke free. I salvaged the screw by grinding it down and cutting a new groove with a tiny grinding wheel chucked onto a dremel tool. Not pretty, but the screw works now.

 

Thanks for the info this works very very well, saved my float bowls.
The Craftsman micro extractors work well. I do however recommend using an appropriate size drill instead of the auger that comes on the extractor. If you break one off in the screw {not that hard to do} it is very difficult to if not impossible to remove. This makes it very hard to insert the extractor into the screw. Using a drill bits seems to solve this problem.

 

Smoting is always the preferred method of dealing with recalcitrant foreign fasteners............

 

WOW thats alot of big words for us motorcycle guys don't ya think. Recalcitrant isn't that a diet pill?

 

Yeah it is, but I figured since it was a holiday, what the heck. you know???

 

A while back someone sugested using heat to free up the screw .
hears my expirence with heating:
a small amount of heat works quite well at freeing the drain screw as long as you havnt totally rounded out the head ,
Heres the problem with using heat : If the pilot orfice in the bowl is filthy ,
and has not been cleaned ,
The varnish inside the orfice will plug the orfice good and tight
The varnish becomes ashfault .
Dont use heat unless bowl is clean as a whistle
No matter how you free the screw , Becarefull not to get anything down in the bottom of the bowl .

 

Just finished up removing my drain plugs this morning... Started Thursday night. Sheesh what a chore!!! My best advise is DO NOT SKIMP ON TOOLS! I bought a cheap 5 pack of Black & Decker screw extractors. Drilled a 5/64 hole per the directions used the #1 extractor. Broke off the tip in bowl number 1... Decided I was using to small an extractor and moved on to bowl number 2. Drilled a 7/64 hole. You guessed it! Broke off the #2 extractor. Took a day off to pout (I mean ponder). Went out bought myself a dremel and various sized bits, went to work on trying to clean up the mess made with the B&D garbage.
Another day later and a craftsman heavy duty Straight Flute No 1 Extractor and I’m a happy camper.
Oh except when I went back to drill number 2 I drilled through the screw and into the threads a little, I'm not entirely sure of the consequences of that mistake yet!?! Don’t drill down at too steep and angle, the screw is barely at an incline!

 

I also used heat and it worked like a charm. As long as it's clean and the heads are in decent shape, this is the easiest way to get them out. I was amazed how easy they came out. I had already cleaned the bowls and soaked the threads with PB blaster prior to using the heat.

 

I second the black and decker comment. Cheap garbage! Broke 2 on the ignition switch bolt which snapped off on me. Lucky for me I know a couple of machinists that milled out my mess and installed a helicoil.

 

I managed to break my extraction bit off in my screw. Then I managed to break a cobalt bit trying to drill that out. Then I managed to drill a hole right through my bow trying to get it out, lol. Luckily Chacal was right there with a new bowl for it and replacement drain screws. Saved my ass. Thanks.

 

Worked like a charm! Thanks, man. One of the bits sheared off when the screw was coming out and was wobbling, so go really slow.

Chacal's stainless screws are fantastic

It was the last thing I had to do before reassembly. This is amazing, the hardest stuff is DONE. Sniff, I love this site, sniff.

Joe from Austin

 

WARNING!

After I put together the carbs, they all leaked like a sieve! Turns out that the stainless screws for the Mikuni are about a sixteenth inch too long. When the head of the screw is seated, it breaks the aluminum seating at the tip and ruins the bowl. Since it is aluminum, there is not much resistance and you can't tell that you are splitting the aluminum orifice at the tip of the screw.

 

wow

 

Umm, I dunno about the Mikuni carb bowls with Stainless steel drain screws but I put them in my Hitachi carb bowls and I had seen a picture of them installed before hand.
The picture depicted them with the head of the drain screws not seated. As in they are a bit too long looking when installed.
If memory serves me, I believe, if you bought from chacal, yes just looked here it is
This is what the description said:

Aftermarket Mikuni bowl drain screws:

The HCP6279 screw is correct for all XJ700-X and XJ750-X models with Mikuni carbs. This screw will also work just fine in all XJ550, XJ650 Turbo, XJ900RK, and XJ1100 carb bowls. The original drain screws on those models had an integral o-ring, which is not present on this replacement screw. The lack of the o-ring on this replacement screw presents absolutely no fit or sealing/leakage issues on those models originally equipped with a bowl drain screw that used an o-ring. Note that by their design, the large allen head portion of this drain screw will be located OUTSIDE of the drain screw bore hole in the bowl, and sticks out about 1/4" from the bowl body. This additonal length does not cause any problems, and after looking at them (installed) on the carb bowls, at first glance they might look "odd" the way the stick out, but after the third or fourth look, they appear normal and oddly interesting with that extended length.


SO when I installed mine I was careful to detect when they bottomed out.
To be honest it sounds like you over tightened them. But again I don't have Mikuni carbs so I'm not certain on that.

 

With a lot of patience and heat i cooked out all of my buggered and rusted-in drain screws with a propane torch. It worked like a charm and i was able to re-use my screws after cutting a nice notch into them with a hack saw and then tapping my favorite craftsman flathead screw driver into the notch so it fits perfectly. Don't forget to apply some anti-seize to the threads before re-inserting the screws after cleaning.

Just apply a couple drops of "olive-oil" onto the screw and place the bowl snugly into a vice. Heat the surrounding aluminum with the torch until the oil starts to boil. Then tap your screwdriver into the screw and turn it out. If it gives you too much resistance, apply more heat and oil. Don't worry they'll come out nice and easy if you repeat the process.

 

After having a miserable time with the screws on my master cylinder. I was not looking forward to trying to get out the carb drain screws on the rack I am rebuilding. In under 20 minutes, using heat and olive oil, I have removed my first carb drain screw. I am so happy right now!

Thanks so much for sharing that tip, Palmer. Makes me wonder if the candle wax got those exhaust bolts out in that other thread.

 

Got all four drain screws out now. Had to use heat and olive oil on all of them. Here are some things that helped me as I went along: clean out the bowls before using any heat as mentioned in this thread (didn't do that on the first one), use a dental pick to clean up the threads on the screws and the area around the head of the screw (mine were rusty and this made a huge difference), and modify a slot screwdriver to fit the head of the screw as best as can be expected.

 

check this out, 2 drain scres, no problem. 3rd drain screw - screw extracter bit, no problem. 4th hah! extracter bit just kept goin in, and in, and in, and in, and in, and in, then BAM! So I think it's safe to say these bowls aren't matched to the main body, right?

 

^^^ Oops!

 

Replacement bowls available if needed, just PM me!

 

Gamuru, I just have to say you have an uncanny ability to state the obvious. OOPS!!!! Your comment probably holds more humor for me since in this particular case it isn't MY carb with the expanded volume float bowl.

I am getting ready to rebuild my ebay carbs so I will be VERY careful to learn from the sad stories in this thread.

I plan to get the Craftsman extractor tool, and I think I will replace my old non self-lighting porpane torch with a new one. Would MAPP gas be a better choice since I'm replacing my propane torch anyway? I understand MAPP is hotter but would it possibly be too hot? I also have oxy-acetylene but I have sworn myself to never get it near the bike. 6000+ deg. seems way hot for anything but steel on steel.

 

I'm no thermal expert, but I don't see any problem using just regular old propane. The carb bowl is probably some sort of pot metal, so it will have a pretty low melting point. The idea--as I understand it--is to expand--using heat--the carb bowl while leaving the drain screw the same size. This will increase the tolerance between the two thread faces and allow you to easily extract the screws. Too much heat could warp or melt the bowl. I've also been told that hitting the screw with penetrating oil after heat has been applied will pull the penatrant up into the threads. This will, of course, cool the area down so you'll need to again apply the heat for a bit.

 

wamaxim, I used a small 5 piece Black & Decker set, it works great too... We know it's stronger than than the screw and bowl!