SuzukiSavage.com - Print Page

SuzukiSavage.com
/cgi-bin/YaBB.pl
General Category >> Rubber Side Down! >> Carb Air/Fuel Mix Screw Removal
/cgi-bin/YaBB.pl?num=1713962953

Message started by ThumperPaul on 04/24/24 at 05:49:12

Title: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/24/24 at 05:49:12

I’m having trouble removing the air/fuel mix screw. I can back it out about 6 turns and then it starts getting stuck. This photo diagram (borrowed from Savage Greg’s old post) shows what appears to be an o-ring, washer, and circlip in the mix screw opening. It doesn’t show the actual mix screw..and these parts aren’t numbered on the diagram.

It’s been a while since I’ve rebuilt one of these carbs and I can’t remember what I did last time (if anything). I’ve already started to scar the head slot on the screw so I decided I needed to stop and try to get some help. I’m wondering if the threads got damaged when somebody removed the brass anti-tamper welch plug covering the screw.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by DragBikeMike on 04/24/24 at 11:59:11

Good luck with that mixture screw. Can you post a picture so we can see what it looks like. If my memory serves me right, some other members have been able to get those screws out by soaking the screw and cavity with penetrating oil and continually cycling the screw (gently to avoid rounding out the screwdriver slot).

I see your post in the Tech Section regarding the carb kit and all the various new parts. Can you tell us more about the carb kit? What is the name of the manufacturer? Who is the seller? A pic of the kit would be nice. I have found the carb kits are a real crap shoot, and they come with a conglomeration of parts that are all chop suey. Once they start mixing all sorts of non-conforming parts you can end up with a carburetor that is impossible to sort out. Every circuit (idle, transition, mid & top) will end up grossly out of calibration.

You mentioned that the new idle mixture screw looked good and had a nice plastic protective cover. Don't fall into that trap. The kits can look top notch but the only way to know if it has a chance to work is by precise measurement.

This old post provides some useful info on the carb kits. Compare your parts to the details provided in the post, then let us know how your kit stacks up. Let us know who makes your kit and who you got it from. Post a reply to the carb kit post so the info can be captured in that post and other members can benefit.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1641171298

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by LANCER on 04/24/24 at 12:57:59

It’s a Mikuni carb, and every jet and needle will have the Mikuni symbol and item specific alpha/neumeric identifier. Both are standard.
If there is nothing at all then don’t use them, as DBM said, you don’t know what your dealing with.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/24/24 at 15:05:06

Thanks guys.

I’m only using the gasket, needle, float valve, and filter screen. The rest is unmarked and simply going off description by the seller. I know these kits are a crapshoot. I thought I might be able to use the air/fuel mix screw if it matched up. But I can’t get the old one out. I think it’s just going to stay there and hope it’s okay. I’ve already scarred the screw head trying to remove it. Stop before I really screw it up. I’ll revisit if it leaks or doesn’t work right.

Link to the kit I bought. I actually bought off a different link by the same seller that didn’t include the description of the parts. He sent the link to this kit (identical) where he included some description. He charges $2 more for the kit with the description. Lol.

https://www.ebay.com/itm/315312946659

I really only bought the kit for the gasket and to look at the parts. Real Mikuni main and pilot jets are coming from JetsRUs.com.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by DragBikeMike on 04/25/24 at 10:49:55

I can see from the eBay picture of your kit that it is bogus. So almost nothing from that kit is compatible with your carb.

Although you are procuring a quality main jet and pilot jet from Jets-R-Us, the two most important components (needle jet & needle) are still gonna be a problem. I can see from your pictures in the other post that your needle is yellow metal, and it has three grooves, and you said it has a strange identifying number on it. So, it's a needle from an unknown source, not OEM. What color is the needle jet? If it is brass, it's probably no good.

When you mix up all these non-OEM parts in the stock carb, you end up with a puzzle that is very difficult to solve. Nothing works like it's supposed to, and you start making changes trying to sort the thing out, and the whole mess runs away.

The needle jet and needle are the two most important components. Get those two items screwed up and you are in for trouble. Howzabout pullin out that needle jet and tell us what you've got in there. And while you are at it, take a pick of your stuck mixture screw. Since you know you have some bogus parts in your carb, there's a good chance you have a bogus mixture screw stuck in there. That mixture screw should be well down in the hole, not flush with the top of the hole.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/25/24 at 11:39:33

I know I'm asking for a mess/challenge using anything out of the kit. You know me!

Photo of the old needle jet. I did install the new one from the kit that looked identical (except cleaner).

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/25/24 at 11:44:21

Photo of the air fuel mix screw that doesn't want to come out. It's definitely way down in there. This photo is with it 3 turns out.

When I tried to remove it, I hit strong resistance at 6-7 turns out. I thought for sure it was going to fall right out at 6-7 turns. When it got stuck, I put it back to 3 turns out and raised my hand to the forum for help.

When I look at the diagram, is there really an o-ring, washer, and circlip down in there? Seems weird if that's the case and I'm looking at the diagram correctly. I can understand an o-ring, but what's going on??

Don't look at the mismatched screws on the TEV (the way I got it). Those will be replaced with stainless steel allen heads once Ace Hardware has them back in stock in a week or two. They were down to just 1 left.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by LANCER on 04/25/24 at 12:13:00

Removing the pilot screw is usually successful by turning the screw back and forth (after you’ve reached the point where it begins to be difficult to turn it) and slowly extending how far it will turn out. An occasional drop of machine oil is helpful as you go along.
You’ve got a fair chance of getting it out this way.
Be sure your choice of screwdrivers fits the screw slot fully, for your best result.

It is possible to drill and use an easy-out but it’s not an easy trick to pull off.
I’ve been successful with this maybe 1/3 rd of the time.

Prayer is helpful, before you begin.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/25/24 at 13:23:52

Thanks Lancer. This is interesting that the dang thing is this difficult to remove. With a 1/3 chance of success, the darn thing is probably staying in there! If it leaks or doesn’t work, I’ll cross that bridge when I get there. I am using what is usually my go-to screw driver for this sucker!

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by Dave on 04/26/24 at 04:40:42

The idle fuel/mixture screw can be a difficult thing to remove. The brass plug that used to block you from accessing it had a small hole in it. Moisture/water can get in there when it is in place, and the moisture allows the threads in the aluminum body to corrode a bit....and that is what is preventing the screw from coming out.

You can lube the screw and try working it out - the brass is soft and it is very easy to strip the screwdriver slot. When that happens it become necessary to drill it out and then use an easy out or a Torx bit to extract the screw. I made a small guide that pushes in the hole and allows me to drill in the center of the mixture screw so that I have the best chance of not disturbing the threads in the carb body. Then I clean up the threads with a tap before I put in a new mixture screw......the tap is very fine thread (still on the road so I cannot tell you the tap size).

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/26/24 at 05:01:09

Thanks for the reasoning and tips, Dave. Safe travels!

I’m going to try again with some machine oil and see if I have a slightly different screwdriver that might fit the slot a little more snuggly. I really don’t want to be drilling and tapping in the small opening.

I went to the carb parts diagram on Partzilla which is clearer and more detailed. Whatever is pictured in the photo above isn’t the air fuel mixture screw. I should find a spring, washer, and o-ring in there.

This is the first time I’ve spread a carb clean/rebuild over 5-6 days. Some of that was simply waiting for parts and cherry picking which parts I might want to use. In a way, I’m glad it’s not just me that’s had trouble with the screw, but I wish it wasn’t the case for any of us!

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/26/24 at 06:57:09

Well. That failed and I screwed up the slot of the screw! And so the fun begins!

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by LANCER on 04/26/24 at 07:05:28

526E736B7663745667736A060 wrote:

The 1/3 chance applied to just the “drill & easy out”.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/26/24 at 07:19:43

And that’s where I’m at now. Screwed up the slot. Is the 1/3 chance for someone as skilled as yourself? So, I have like a 1/10 chance…right?

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by LANCER on 04/26/24 at 07:34:09

You’re the judge on that, I’ve never seen you operate.
If the drill damages the threads in the carb body, it’s toast.
If you drill out the upper portion of the screw and leave the bottom portion inside, it’s very hard to retrieve that remainder. The carb body is toast.
You must be very accurate with the drilling and use of an easy out.

Don’t give up on working the screw in & out with a little oil, it’s your best bet, be patient, it usually works, and keeps your threads intact.

You will want a new screw as replacement since the head is damaged on this one, and also the washer, o-ring & spring. Get the set just in case any of the other 3 items is lost or damaged…or were missing.

Keep any of the old parts that are usable as backup, just in case.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by verslagen1 on 04/26/24 at 08:48:48

There's a tip on using a torx bit somewhere to extract the idle screw.
I'll see if I can find it.

Wasn't hard to find, it's in the tech section index...

https://suzukisavage.com/cgi-bin/YaBB.pl?num=1350749896/0

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/26/24 at 10:09:38

I screwed the pooch! I now have a $500 paperweight if anyone needs parts. I’m too embarrassed to share pictures of the butcher job I did. I should have just left the darn thing alone!

I’m going to install a PWK38 Air Striker. I was going to save that mod for later. Now, later is now.

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by Savard 05 on 04/27/24 at 03:40:48

When I got my bike someone mangled the pilot fuel jet and I had good results with easy out kit using smallest size and the left hand drill extractor. But that was easier than your air needle jet because the pilot jet already had a a small round hole so not much drilling was needed. Anyway might be worth another try. Good luck!!!

Title: Re: Carb Air/Fuel Mix Screw Removal
Post by ThumperPaul on 04/27/24 at 05:39:58

It’s toast. Drill bit slipped off course and I bored a hole straight into the bore of the carb.