Howto: Replace your stuck carb drain screws

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