Air Screws in Stock Carbs

General forum on engines, transmissions, gearing and modifications to each

Moderator: rztom

Post Reply
Message
Author
BoldRZ
Posts: 77
Joined: Tue Oct 07, 2003 5:17 pm
Location: Boulder, CO

Air Screws in Stock Carbs

#1 Post by BoldRZ » Wed Jul 19, 2017 6:44 pm

I'm going through my bike that has been sitting for a while and read a couple of threads on here about cleaning up the carbs and people having "jelly" in different ports/passages on their carbs.

Someone had even pulled the air screws out of theirs to clean that area up.

So, I took everything out of my carbs to remove the built-up varnish and also any potential "jelly". I got everything apart and then it came to the air screws. The guy ahead of me had removed the caps and obviously adjusted them because one of the slotted heads on the air screw was messed up. I started backing the air screw out and it was pretty tough. I tried screwing in a half turn and then out to clean any debris but I ended up messing up the head of the air screw.

My first question is can the air screws even be removed from the stock carbs? It seemed like they just stopped turning and with the original cap on there, I started to think that maybe they can't come out.

My second question is, now that I have totally messed up the head of the air screw, how can I get it out. I've never seen an "easy-out" that small and the thought of trying to drill a hole in it seems pretty difficult.

My last question, until I mess something else up is does anyone have a part number for the air screw for the stock Mikuni carb? I talked to Sudco and they said compare the air screw to the different photos on their Facebook page. If I've drilled it out and messed it up even more, I'm not sure I'll be able to do that.

Any advice is greatly appreciated! Thanks!

Nils

waltmil
Posts: 491
Joined: Fri Dec 28, 2012 9:23 pm
Location: Panacea, FL USA

Re: Air Screws in Stock Carbs

#2 Post by waltmil » Wed Jul 19, 2017 9:38 pm

It looks like you have the stock US carbs. I have the same and have tried to find replacement air screws and they do not seem to be available. I have been able to remove and adjust them but the screw slots are a bit buggered. Since my bike is running good, I am going to keep it as is. If I start having trouble I will probably get some PWKs. If that doesn't suit you, try to find a good set of Canadian stock carbs and cables.
Red/White US '84, Spec II pipes, Y-boot w/K&N, Fox Shock, Mikuni carbs?

mc84721
Posts: 17
Joined: Sat Nov 12, 2016 5:30 pm

Re: Air Screws in Stock Carbs

#3 Post by mc84721 » Thu Jul 20, 2017 12:58 am

10w-14104-00 is the Yamaha Part number for the screw. They are all over eBay. Banshee is probably the same air screw too. I was a like​, thats odd, mine doesn't have that..must be for US emissions. Mine is Canadian.

Sent from my XT1254 using Tapatalk

Srhiskx
Posts: 80
Joined: Sun Sep 30, 2012 6:28 pm
Location: Cedar Rapids Iowa

Re: Air Screws in Stock Carbs

#4 Post by Srhiskx » Thu Jul 20, 2017 1:05 am

HVC cycle has them. 28.00 for a set for the RZ350.
84 RZ350 Allspeed GP replica pipes, milled head, PWK 28mm Keihins, Y air boot/ k&n filter, VForce4’s, Zeel, Dynatec ignition coil,R6 calipers, Ohlins, sonic springs 80wt fork springs, FZ1 master cylinder.

waltmil
Posts: 491
Joined: Fri Dec 28, 2012 9:23 pm
Location: Panacea, FL USA

Re: Air Screws in Stock Carbs

#5 Post by waltmil » Thu Jul 20, 2017 6:54 am

Maybe it was an error but I ordered a set a few years ago and what I got didn't fit the my US carbs.
Red/White US '84, Spec II pipes, Y-boot w/K&N, Fox Shock, Mikuni carbs?

BoldRZ
Posts: 77
Joined: Tue Oct 07, 2003 5:17 pm
Location: Boulder, CO

Re: Air Screws in Stock Carbs

#6 Post by BoldRZ » Thu Jul 20, 2017 1:56 pm

mc84721 & Srhiskx,
Thanks for the input on obtaining air screws.

I looked at the 10w-14104-00 air screws on ebay and the different applications but it doesn't look like they are for my RZ350. I forgot to mention that mine is an '85.

The air screws that HVC cycle has sound like they are the correct ones. I called them up and I think that these should fit what I need. I just have to get the old ones out now. Hopefully that doesn't cause any other problems.

Waltmil,
You might look at HVC Cycle (http://www.hvccycle.net" onclick="window.open(this.href);return false;).

I'll let you all know how it goes.

Nils

waltmil
Posts: 491
Joined: Fri Dec 28, 2012 9:23 pm
Location: Panacea, FL USA

Re: Air Screws in Stock Carbs

#7 Post by waltmil » Thu Jul 20, 2017 8:08 pm

I have in my hand the 10W-14104-00, Yamaha PN and they absolutely do not fit US RZ350 carbs. Let me know what you get from HVC.
Red/White US '84, Spec II pipes, Y-boot w/K&N, Fox Shock, Mikuni carbs?

mc84721
Posts: 17
Joined: Sat Nov 12, 2016 5:30 pm

Re: Air Screws in Stock Carbs

#8 Post by mc84721 » Thu Jul 20, 2017 9:13 pm

Care to post a picture? I'm curious to what they look like.

Sent from my XT1254 using Tapatalk

waltmil
Posts: 491
Joined: Fri Dec 28, 2012 9:23 pm
Location: Panacea, FL USA

Re: Air Screws in Stock Carbs

#9 Post by waltmil » Fri Jul 21, 2017 9:13 am

I revisited eBay today and the air screws from HVCycle look to be correct. They are a bit pricey at $28 US plus shipping but I ordered a set. EBay also still shows the incorrect 10W-14104-00. They are cheaper but they won't fit.
Red/White US '84, Spec II pipes, Y-boot w/K&N, Fox Shock, Mikuni carbs?

BoldRZ
Posts: 77
Joined: Tue Oct 07, 2003 5:17 pm
Location: Boulder, CO

Re: Air Screws in Stock Carbs

#10 Post by BoldRZ » Fri Jul 21, 2017 4:44 pm

Waltmil,
Thanks for checking and confirming that the air screws will work for your '84. I'm assuming they will also fit my '85.

I had to take my carbs to a shop to drill out my old air screw so I'm waiting to see what comes out of it. Hopefully the carb is still good when they are done. Otherwise I'll have to get some different carbs. Ugh!

Srhiskx
Posts: 80
Joined: Sun Sep 30, 2012 6:28 pm
Location: Cedar Rapids Iowa

Re: Air Screws in Stock Carbs

#11 Post by Srhiskx » Fri Jul 21, 2017 9:29 pm

I had one air screw stuck in my carbs, I took a small drill bit and CAREFULLY drilled the head and tapped a small torque screwdriver into the hole. Then back the screw out. On choosing a bit I just pick one the was close to the size of the torque screwdriver I had. Be really careful on drilling the head of the air screw , I didn't go to deep, just enough to get a good grip with the driver.
84 RZ350 Allspeed GP replica pipes, milled head, PWK 28mm Keihins, Y air boot/ k&n filter, VForce4’s, Zeel, Dynatec ignition coil,R6 calipers, Ohlins, sonic springs 80wt fork springs, FZ1 master cylinder.

waltmil
Posts: 491
Joined: Fri Dec 28, 2012 9:23 pm
Location: Panacea, FL USA

Re: Air Screws in Stock Carbs

#12 Post by waltmil » Fri Jul 28, 2017 2:11 pm

Thanks BoldRZ, I swapped my chewed up left air screw for the new one from HVCCYCLE and somewhere some environmentalist has a headache and he doesn't know why. I rode my bike before and after and it runs fine. Gloriously smoky but too hot for much of a ride. Good luck getting your buggered screws out. Mine was harder than it should have been as I have had it out twice before.
Red/White US '84, Spec II pipes, Y-boot w/K&N, Fox Shock, Mikuni carbs?

BoldRZ
Posts: 77
Joined: Tue Oct 07, 2003 5:17 pm
Location: Boulder, CO

Re: Air Screws in Stock Carbs

#13 Post by BoldRZ » Sun Jul 30, 2017 6:05 pm

Waltmil,
I've ordered my air screws from HVC Cycle. The should get here early this coming week.

How do your old ones compare?

Also, getting both of mine out were a BIG ordeal! They had to be drilled out.

Can you confirm that on the air screw there was a washer, o-ring and spring in that order? When the first was drilled out, when it released out it popped out and went flying. I got the spring but no washer or o-ring. The 2nd went better and that one had a washer, o-ring and spring (in that order).

Did your's have the washer & spring? I asked HVC and they do not have the tiny washer or spring. Any idea where to find that stuff?

I'm glad yours is going well. Hopefully mine will be up and running very soon.

Nils

waltmil
Posts: 491
Joined: Fri Dec 28, 2012 9:23 pm
Location: Panacea, FL USA

Re: Air Screws in Stock Carbs

#14 Post by waltmil » Mon Jul 31, 2017 5:46 am

Mine had spring only, the o ring and washer were gone when I got it. But the incorrect 10W-14104-00 screws came with o rings so I used those. No idea where to find the washers. The washer should be between the spring and the o ring to protect the o ring. The HVC screws look identical to the original screws. Just make sure you use the proper screwdriver when you install the new ones.
Red/White US '84, Spec II pipes, Y-boot w/K&N, Fox Shock, Mikuni carbs?

BoldRZ
Posts: 77
Joined: Tue Oct 07, 2003 5:17 pm
Location: Boulder, CO

Re: Air Screws in Stock Carbs

#15 Post by BoldRZ » Mon Jul 31, 2017 10:02 pm

Waltmil,
Great idea to try the O-rings from the 10W-14104-00 air screws! I wish I would have seen your post earlier.

I went to a Hobby Store that has a bunch of remote control plane and car stuff. I showed them the washer and o-ring from my carbs. They looked around and here is what they came up with.

They had a Traxxas 5355 Hollow Ball Set that has some "shims" in it that come pretty close to the washer. Here are the measurements that I got from my stock washer and the thinner of the 2 shims in the set:

Stock OD - .197"
Stock ID - .123"
Stock Thickness - .02"

Traxxas OD - .196"
Traxxas ID - .121"
Traxxas Thickness - .045"

Here is a link to what I got - https://www.amazon.com/Traxxas-5355-Hol ... axxas+5355" onclick="window.open(this.href);return false;.

In the picture, I will be using the thin shims at the bottom of the picture.

The shim is .025" thicker than the stock washer. I'm not sure what that would equate to in terms of "turns on the air screw" but all of the way in the air screw will be leaner than stock if you didn't turn it out at all.

As far as the O-rings, they had a Traxxas 5247 Carburetor O-Ring and Seal Set (2.5, 2.5R). The link for that is - https://www.amazon.com/Traxxas-5247-Car ... axxas+5247" onclick="window.open(this.href);return false;.

In that picture, the black tiny O-rings seem to be very close to the size of my stock o-ring.

My air screws should be coming from HVC tomorrow. Once I get things all together I'll post how things are going.

Post Reply