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?