Float Adjustment Help (Video)

[HuD 91gt]

Hi guys,

 

i'm just rebuilding my first set of SU's (and carbs in general), and I have a question about adjust the float. I've sent an email to Bruce @ Ztherapy, and I am waiting a reply but I know you guys can be pretty quick so i've posted here as well.   The reason i'm concerned is that my Z was running decently prior to disassembly, and now following the instructions for proper float adjustment i've have to make some decent changes to the float to get it within spec.

 

Here's the video, and let me know if i'm doing this correct.  I'm also experiencing some stiction when close the valve, I assume moving the valve lower with some washers should help.  How many can I add?

 

 

 

http://youtu.be/gofNHzRZp9c

[siteunseen]

I turned mine upside down and moved the .55" in and out, bending the tab until it wouldn't move the float anymore.  Make sure it's closing off by attaching a short piece of hose to the fuel inlet and blow into the valve.  It shouldn't let any air blow through when it is at the right height and the pin is depressed in, closing off the valve.  Try to suck air out too.  I ended up with a bad valve that wasn't opening.  Bruce sent me one overnight, great folks to do business with.

 

 I may have that backwards, it's hard to explain in text and I have no idea how to do video but it will make sense when you start blowing into or sucking air out.  It's opposite of a schrader valve on you car tire, pin fully out lets fuel into the chamber, pin pushed in closes off the flow.

 

I'm pretty sure I used one washer on the front carb to get the right height, it has the longer arms doesn't it?  Maybe I used one on the rear and two on the front?  I apologize if I've confused you.  Turn the chamber lid upside down, it's easier to figure out that way.

Cliff

[HuD 91gt]

When I spoke to Bruce on the phone, he said to specifically do it the way I posted in the video(the orientation of the lid).  I was originally doing it the way you explain, as that is the way i've read online.  I haven't heard a reply from him since I sent him the video.  I guess we will see.

 

I just disassembled the second carb, and when I do the test of it, the 14mm spacer is a perfect fit when the tab just makes initial contact with the valve.  Obviously the float could continue to raise until the valve completely shuts about 10mm higher up.  

Anyone else have any more input?  This measurement should be taken when the valve completely shuts, and no more air can be sucked/blown through, correct?

[HuD 91gt]

Also, I have one long, and one short tab.  Both valve in the Ztherapy kit are the same.  Is that correct?

Edited March 12, 2015 by HuD 91gt

[NVZEE]

Yes, replacement valves are in one length these days so shimming helps make up the difference. Also note that the rod on the valves is different from OEM -- longer and the end that contacts the float tang is more squared-off. That means that the tang shape needs to be bent accordingly so the rod will follow the ramp smoothly. Bruce and Steve reminded me that this is all part of the tuning process when I asked them about it.

[HuD 91gt]

Steve from Ztherapy just got back to me, and told me to actually put the lid horizontal (90 degrees from what I have in the video), and to test it that way.  He also stated the needle/seat are the same for both long/short ears these days so a decent amount of bending is required.   That cleared up my questions nicely I think.  I'll post my results, and perhaps another video for others with this question for the future.  I think the video is a nice visual learning tool.

[HuD 91gt]

Thanks NVZEE, I think I got the phone call the same time as your reply!

[NVZEE]

For comparison -- replacement float valve is on the left.