KZ750 LTD Keihin CV34 Carb Questions

Believe me, I'm well familiar with using tight fitting screwdrivers. I did just that and the slot in the plug was starting to get buggered from the torque of turning. I'll try soaking the plug in PB Blaster for a day or so and try again. Maybe a soldering iron on the screw will allow some localized heat. Fingers crossed.

akolleth wrote: I guess worst case if you do damage the diaphragm there is a company that makes new replacements, although pricey at $20 a pop

jbmindustries.com/Keihin_diaphragm.html

The problem at hand is corrosion on the tip of one of the needles. I've got one diaphragm that's cut on the end too so those replacement diaphragms may come in handy in the future. I'm not crazy about the fact that they are not secured to the slide better though.

The tip of the needle shouldn´t be a problem. Can you post a picture?

undiablo wrote: The tip of the needle shouldn´t be a problem. Can you post a picture?

I know the corrosion can be scrubbed off with scotchbrite but the anodize is gone. I've got another slide with a torn diaphragm so I figure the good parts can be combined. These will just be spares at this point anyway. I've got clean parts for the project carbs already.

EDIT: I was able to remove the threaded plug after wrapping the slide in duct tape and then carefully clamping it in a vice before using two hands on the screwdriver.

Good work Nessism! Glad to hear that.

One last little tidbit of information about rebuilding these Keihin's...

In order to ungang these carbs for proper servicing the choke butterfly shafts must be removed. Problem is the butterfly shaft screws have a hollow tip and Kawasaki calls for using a special tool after assembly to flare out the end of the screws to help retain them during use for fear of the bike ingesting a loose screw. Kawasaki used to sell a special service kit including the choke shafts and new screws but those parts are long out of production.

During assembly of the carbs I used red loctite on the screws to aid retention. I also made a little tool to flare out the screw end. Nothing special here, I just took an old needle file, because the metal is very hard, and ground a rounded point in the end. I then cut off the end using a cut off wheel thus creating a small pointy nib so to speak. I attached this nib on the jaws of some high leverage channel lock type pliers and placed the nib point in the hollow tip of the screw and the other jaw on the head of the screw, and then squeezed as hard as I could. That should do it!

Finished! Glad that's over with! Struggled to get the float height set properly. I don't know what it is about these Keihin's but the float needles seem finicky, even with new needles.

P1030119 by nessism , on Flickr

P1030115 by nessism , on Flickr

The seats really suck also.


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Nessism - Carbs look great, nice work!

Just to wrap up my side, I finished cleaning my carbs and that solved the misfire issues on the bike - the bike is running fantastic now. I ended up buying a parts bike for a bunch of extra parts I wanted, and it had a nasty set of carbs with it, so I stole the pilot jet plug off of that bike. The bike I bought was a KZ750E, and I'm going to swap to that dual exhaust because I like it, so I think I will also swap the carb jets to the larger sizes on those and see how the bike runs after that. It not, I can just swap back to the smaller sizes. Thanks for all the help!

Edit: Forgot to mention, the carbs were super clean when I took them apart in really good order. I cleaned them the best I could, but I do think my issues were coming from a missing plug ion one of the pilot circuits.

my 81kz750ltdh3 has a 62 and 125 jet

It's nice to see this thread resurface. I've rebuilt more half dozen sets of these carbs at this point and have learned a lot about restoring them which I'd like to share.

First, the various O-ring sizes are thus...
Pilot Screw: 1.2 x 2.6
Pilot Plug: 1.5 x 2.8
Fuel Transfer Tubes: 2.0 x 5.5
Drain Screws: 1.4 x 4.0
Float Bowl: 2.0 x 67

Secondly, the earliest version, from 1980, have float bowls with a brass overflow tube that often cracks. The tube can be fairly easily replaced using 1/8" brass tubing commonly available at hardware/hobby stores. Use a slow moving drill motor and put the chuck around the old tube and tighten, then spin and pull the old tube out. Take an old drill bit and grind the end a little to flare out the end of the tube a little - from .125" OD to about .130". Another thing is to spin the piece of tubing with the drill motor (or lathe if you have one) and use the dimple on a threading die to roll over the end of the tube like the original tube. Last step is to cut the tube to length and press it into the float bowl using a vice with soft jaws. I've done quite a few float bowl repairs this way and it works every time.

Good fun

This thread has been a great deal of help, along with some extra tips from Nessism, One carb clean and ready to assemble, three more to go!