TOPIC:

Wow, that certainly is clean! If they're all like that you should be in good shape.

Just thought of something: are these the type of carbs that have the diaphragm in the top? Perhaps the one on the right is damaged in some way. You can compare to the ones from the parts bike. I'm starting to run out of ideas and hope someone smarter will chime in.

As an aside, I believe you can swap in the electronic ignition from the '81 into the '80 (and get rid of the points).

Yep, these have the diaphragm. I'll just swap left and right to see if the issue follows the parts or stays on the same side.

Thanks for the ignition tip. Checked the parts bike and it does have electronic ignition. Will see what it takes to swap out.

A few updates...

• No issues on the diaphragm.
• I decided to test my theory of the bad o-ring on the HF compression tester. I put a new one in and tested again. With the engine cold, I got 90 psi on both sides.
• Looks like the ignition swap will require some wiring mods.

I think the issue is in the carb, specifically at idle. I believe that at higher RPMs the right side is actually firing. I get popping from the exhaust and can feel the air coming out hotter. Is there any way to confirm this is?

The bike still has issues at idle. I bought carb rebuild kits from Z1 to see what that does. Ihave a few questions on some of the items that came with the kit though - looking for some help...



1. Inside the float bowl o-ring, top right corner (silver screw) - what is that for / where does it go? I can't seem to find it on my carbs (Keihin CV36)
2. I think the two large o-rings are for the fuel t-adapter; smallest o-ring is for the mixture screw (goes w/washer). What is the medium size o-ring for? It seems to big for the pilot needle plug or for the drain screw.

Here some pics with the o-ring locations

esquare12 wrote: The bike still has issues at idle. I bought carb rebuild kits from Z1 to see what that does. Ihave a few questions on some of the items that came with the kit though - looking for some help...

1. Inside the float bowl o-ring, top right corner (silver screw) - what is that for / where does it go? I can't seem to find it on my carbs (Keihin CV36)
2. I think the two large o-rings are for the fuel t-adapter; smallest o-ring is for the mixture screw (goes w/washer). What is the medium size o-ring for? It seems to big for the
pilot needle plug or for the drain screw.

Some times kits are supplied with parts for more than 1 application.


.

I was hoping to get the pilot jet plug o-ring with the carb rebuild kit but that did not happen. Instead of having to wait a week or more for the stock part I bought the Viton o-ring kit from Harbor Freight, took the smallest one and sanded it down to size with a drill, fine grit wet sandpaper, and some WD-40. Worked fine, no cracks; very tight fit. I went ahead and replaced the pilot screw o-ring as well. Also blew some air through the pilot air jets (inside the rear opening of the carbs). I left all the other stock needles in place as I did not want to bring in more unknowns by replacing a bunch of parts.

While I had the carbs out, I decided to recheck the float levels; had to tweak the adjustment to get the right height (was a bit low). Put everything back together and the bike started on the first crank. Both cylinders are working fine now.

New Issue - Revs going up when clutch is pulled.

I drove for a while and noticed that the acceleration/engine noise was strange, as if the clutch was somehow still engaged. Went back to the garage and adjusted the clutch cable. I am not quite sure that fixed the problem though. Took it out again... when I pull the clutch in the revs go up and stay up until I start to release the clutch. Then it drops down and stays down. At a stop light, if I blip the throttle the revs won't come down unless I start to engage/release the clutch. Driving, while in gear, pulling the clutch makes the revs go up (with no throttle applied).

Control/adjust your clutch/throttle cable routing/slack.

I adjusted the clutch and it still sometimes stays high on the revs. Throttle slack and adjustment is also good. Only way I found to manage it is with the idle adjustment... but I have another issue now; on to the Engine forum I go. 

Noobie here. 79kz400h. Similar problem to yours.  Right cylinder not running. Unless I cover the intake with my hand and let air through with my fingers creating vacuum. Did all the same checks as you. Guess I'll pull the carb and look at it again. Do you think the float level was the issue or the oring you replaced? 
Thanks, 
George