Air Jet TIGHT!

[Guest]

Hey everyone.
I've been in the process of rebuilding my carbs over the last few weeks (It's been really hectic at school so I get to them when I can).
I've completed two, and have the third apart, but had an issue with the Air Jet on my carb #4 (following the numbering system in the Carb Rebuild Bible).
It was a struggle, but I was gentle and had a good fitting screwdriver to get the Air Jet out. I cleaned the Jet with carb cleaner as well as the orifice (giggity) that it threads into. I tried to reinstall it after I was done cleaning and found it was exceptionally tight and I could not get it to thread in much beyond being flush with the top of the column it goes into. It's maybe 2 turns below that. I can't put it in any further without the screw driver slipping out of the slot and if I do much more it's going to strip and I'm going to be in a world of trouble...any advice?

I have not tried swapping the Jet with one from another carb to diagnose if it is the screw or the threads yet... I'll be doing that a little later this afternoon.

[cp___32]

I just tried to swap the Jet from that carb with another Jet and another carb that turns freely. The sticky Jet is a little less sticky in the other carb body...and trying a good Jet in the sticky carb body doesn't go so well.
So it's definitely a combination of the carb body and the Jet.
If I were to go to the dealer, chances are they won't have that part in stock, so is it very model specific or should the Air Jet, and the Spring be a fairly common stock part with many different carbs?

[cp___32]

Sorry...it's the AIR SCREW that's the problem...the assembly with the Air Screw, Spring, Washer and O-ring found on page 15 and 16 of the CV Carb cleaning guide

[uudfourty]

If its the screw I'm thinking of, make sure that the washer and o-ring beneath the screw haven't gone vertical on you and are preventing the screw from seating.

[cp___32]

Yeah I've checked for that, and tried installing it upside-down and also just the screw itself without the spring, washer or o-ring. I've cleaned the threads on the screw, cleaned the threads in the hole the best I can, it threads down till the threads at the very top of the screw catch and then it stops.
I checked with the dealer and they said that since it's not listed in the fiche that chances are to get one through them I'd have to order a new carb (which they didn't recommend for the sake of a screw) I could try to clean the hole with a tap and clean the screw with a die, but I don't know where I'd find a M5 x 0.5 die locally.
MC Distributing used to make an EZ adjust screw at $30 a screw. Those looked like a great option till they told me the part was discontinued. My last hope right now is that the local scrap yard has a junker carb that they can pillage for the screw, he said $5 if he can get one, but he's not sure they have a broken carb they are willing to part out.
So again I ask...any advice?

[ChicagoRob]

Mikuni CV Air Screw

I may have one for ya.

When I did the boy's carbs, I ordered a couple from here:

http://www.mikesxs.net/products-37.html#products

Turned out the ones that I got are a bit taller than stock. In spite of that, they still work. The tip of the needle is the same size and the length from the tip of the needle to the oring is the same. Since it's taller in the shaft, it doesn't have to thread down as far, so your bad threads may not be a problem. I'm currently running one of these in the boy's #2 carb.

Other than the guy above, Z1 sells a rebuild kit with a screw in it. That's better than buying a whole new carb from the dealer. :-)

You could post a "carb body" request in the wanted forum. It'll be cheaper than you think and easier to find than a really fine pitch tap. Be sure and mention the carb #. It makes a big difference.

If you'd like my screw, PM me your address and I'll drop it in the mail.

Rob

(Sorry about the bad cell phone pic, but it gives you the idea.)

[dstamour]

I have a brand new air screw left over from a rebuild kit for my 650 you can have. I bought the rebuild kits and then everyone said to stick with the original parts out of the carbs. I had to open 2 of them for the pilot jets. Pm me your address and i will send you the screw, spring, washer and oring.

Donald