Project P51: 1980 KZ 250 LTD cafe racer (ish) build

P51 Update #1:
Thanks for the add! Just bought this 1980 KZ 250 LTD! It’s got about 20,000 miles and runs pretty decently (although it may be running a bit lean/has a hard time idling, I’ll post a video soon). Plan is to create a pretty sweet cafe style build with this.
 

-NFSG

I’m in! Welcome. 

Welcome from the UK, let's see what you can make of it 

P51 Update #2:
Troubleshooting for difficult idle and running lean? (1980 KZ250 LTD)
Currently working on getting the bike to idle and run a little bit better. I’ve noticed that it doesn’t really like to idle, and I’ve seen the exhaust pipe start to glow red so I think it might be running a bit lean. any thoughts on how to solve these issues?
I just took apart the carburetor, and it looks very clean on the inside. One of the jets had a plug on top, so I removed the plug (plug still on in pictures) in hopes to get the bike running a bit more rich. I think it’s lean because the original airbox has been replaced with some aftermarket parts. I also tinkered with the idle screw a bit before taking the carb off, which seemed to help a little bit
   
   
-NFSG

That rubber cap is necessary for the carburetor to function properly. The lean condition may be because the previous owner did not rejet after changing the intake system, or it could be from a dry, hard, cracked carburetor holder, or both. Could also be that the fuel level in the carburetor is too low.

I'll second that the rubber plug is necessary; the pilot jet beneath it draws fuel from the main jet, and if the plug isn't there it'll likely run very poorly (I've experienced this). 

If you ensure everything is in spec and you have no air leak, then it's probably a rejetting situation. Looks like you can use jets that fit Keihin CV34s, so shouldn't be too hard to find larger sizes. 

P51 Update #3:
Running too rich? Continuing tune-up (1980 KZ250 LTD)
    
Could use some advice, as I’m new to carb work (and stuck haha).
in the video I don’t actually press the kill switch, the engine dies when I try to turn the throttle (it’s currently too rich)
Since the last update, I removed a plug that I found in the carburetor covering a jet. When I put everything back together it definitely wasn’t running lean anymore, I think it is actually running so rich now that The spark doesn’t always happen due to too much fuel. I tried turning my idle screw clockwise until it wouldn’t go any more and it’s still running rich. Here is a picture of a brand new spark plug with two minutes of ride time.
I'm thinking maybe I should put the plug in the carb back in and get a pilot jet with a bigger size? Not sure exactly what to do. I also looked around the engine a bit and there doesn’t seem to be any gas leaks anywhere, which I suppose is a good thing


*edit: Well, I did the above work and subsequently wrote the above post before reading the comments I got on my last update...oops. Well, hindsight is 20/20. Would have definitely saved me some time listening to y'all lol. That plug was definitely necessary, and I have since lost it....not a great time either since I cannot find a replacement one anywhere. I checked my local kawa dealer, and looked everywhere online, and could not find that plug or even an OEM carb for that matter (would have bought the whole thing just for the plug haha). @TexasKZ I did notice that I do indeed have a cracked carb holder, and I'm going to double check but I think I found that online for pretty cheap so I will definitely replace that. I'm also thinking about getting an entire aftermarket carb (found several online that say they fit my bike), since I can't find the plug (the new carbs are only around $40). I'm curious as to what everyone thinks? (also....@ghostdive how were you able to figure out I have a Keihin CV34?! I knew the brand but could not figure out the model haha.) 

I will probably make a follow up post here or somewhere else with a list of the parts that I need, in the hopes that someone here might have them lying around. Not betting on it too much though, leaning more towards buying a "new" aftermarket carb and then re-jetting it from there until it runs correctly. Doing carb work is completely new to me, so I appreciate everyone's help and patience haha.


-NFSG