1978 kz1000a renew and revenge project

bry195 wrote:

Hi all — first off, thanks for the help and the knowledge here. I’m grateful for the experience this forum brings.I’ve tuned a lot of carbs (and done plenty of EFI builds), so I’m not expecting carburetors to behave like EFI. I’m using a single wideband to guide changes with a simple goal: a bike that starts, runs, and travels reliably. Power and efficiency are secondary. Ive tuned inline 4 motorcycle engines with carbs and oxygen sensors many times over a 15 year period. It wont be like efi but it will be as good as anything else. The point isnt to pursue perfection. The point is to run in it in the cold/warm/altiitude/fuel grades and find the best compromise or middle ground. But most of all I will be making changes based on the experiences ive already had and combining them with specifics I learn from you on the kz1000.

On jets: my mains are close to what’s been suggested. I’m currently experimenting with non-Mikuni jets. I don’t recommend that route for most people, and I only went there because I’m comfortable measuring/machining and accepting the risk. For anyone not wanting that risk, please follow the standard recommendations from the folks here.

On the choke plunger: I really appreciate the documented fix — totally agree it’s a common, under-diagnosed issue. Regarding “rubber rejuvenator,” I want to be clear: I’m not proposing it as a general solution. I’ve experimented with removing oxidized outer layers and re-plasticizing rubber (background in race-tire prep), and I’ve seen temporary improvements that are impressive (from full loose to full push). Longevity is unknown and likely limited; I’m treating it as an experiment on my own bike, not advice. For what it’s worth, I verified every circuit, including the choke, with a leak-down test before and after. 

Big picture: I’m not trying to upend KZ best practices. I respect the established guidance here and wouldn’t tell others to do what I’m doing. Some of us enjoy pushing the edges and owning the consequences — that’s on me, not the forum. If my path earns an “I told you so,” that’s fair.Thanks again for the continued guidance.

By the way, has anyone used the BS series carbs? inexpensive, for oil cooled, and one of the best carbs ever.

bry195 wrote:

Those BS carbs were really good in the transitions from mid to wot. Really good at elevation too.


He has a stock 76 kz900 with 4/1 and pods. still running points and has 120 main jets. plus the last time he actually did more than start it was 10 years ago. I dont think it will be too much of a problem. My bike is the same except it’s a 1000, carbs will be dialed in (air correction jets too) and electronic ignition with hot coils. All new tires and bearings . 

Is the 1000 faster than the 900 in a quarter mile?

 

• 1976 KZ900 (903 cc): ~12.2–12.4 sec @ ~110–112 mph ¼-mile; top speed ~130–132 mph.
• 1978 KZ1000A (1015 cc): ~11.7–12.0 sec @ ~114–117 mph ¼-mile; top speed ~133–136 mph.

bry195 wrote:

You bet I will. That would be fun. Have you got any secrets to share about unlocking a few ponies in the KZ1000?

wrote:

I never said that I—or ChatGPT—had all the answers. So I’m not sure why you’re implying that. If you can’t respond to the actual content and instead focus only on emotion or dismissiveness, then maybe it’s better not to respond at all.

ChatGPT simply analyzed 20 years’ worth of KZR discussions and summarized the patterns and logic behind them. If you think it’s wrong, that’s fine—just point out where and why. That would actually help the conversation. But to call it “garbage” without offering any reasoning isn’t productive and it diminishes all of us.If you disagree, explain your logic (this would be very interesting because AI is pretty good, but it is wrong). If you have more accurate or detailed information, share it. That’s how we all learn. Nobody is claiming it’s perfect or definitive—it’s just a useful starting point for discussion.

I’m not posting things to show off or to argue. I’m contributing ideas so we (or I) can figure things out together, you arent required to contribute. I don’t need the basics explained, but I’m willing to listen out of respect for others who are trying to contribute honestly. I wont intentionally make you feel like you arent appreciated/respected unless you cannot return the same.We shouldn’t be creating an environment where people are afraid to post something that’s within the rules. So if you have a logical point, let’s hear it. If not, maybe just move on