1980 KZ1000 A4 MKII Barn Find

I learned two lessons the hard way, both relating to the carbs. I haven't been happy with how the bike runs when it's first started....really, really "cold blooded". I decided to check the service fuel level using the clear tube method. The float levels were all off...all were much too high. 1st lesson....Never count on setting the float height by measuring the floats, always measure the actual fuel level. I had them all set perfectly to 26mm and the actual fuel levels were all way off.

While I was setting the levels, I could not get the #2 carb to stop filling...it would slowly trickle until it got way too high no matter how much I bent the tab. I finally pulled the BRAND NEW needle and seat out for an inspection and planned on polishing them up a bit. I found a huge metal chip in the seat! 2nd lesson....Never assume that new parts are good just because they are new. They all need checked and/or cleaned before installation. I've read this before but didn't bother to check them when I put them in. Lesson learned. :blush:

The float levels are all great now so hopefully it will solve the cold start issue. For the record, the service fuel level for the '79 and '80 MKII (28mm pumpers) is a little different than most...it's 3mm - 5mm. The LTD models might be the same, not sure. This is according to the factory service manual, in the supplements for the 1979 A model and the 1980 A model.

Here's what I found in the needle and seat!

I bought the Meguires "Ulitmate Compound" at Auto Zone and thought I'd give it a try. That stuff is AWESOME! It took old gas stains and oxidation and all that stuff off the paint...what a great product. :woohoo:

I've got it pretty well cleaned up now...here are a few pics:

They make really great products. Your bike looks like it's new! Ed

It looks better in the pictures than it does up close...you know how that goes. There are plenty of scratches and nicks from its 32 years. Sure has come a long way though.

I've still got a cold start problem. It only runs on one or two cylinders for the first 60-90 seconds and then the others just kick in. It's really hard to keep it running when I first start it. It didn't do that with the 26's on there so I'm thinking it's the carbs. I've checked spark on all 4 cylinders while it's running like this and it's there. It also seems like the air screws do very little to change the idle.

Any idea what in the carbs could cause this condition? I can touch the pipes after its run for 30 seconds or so and only 1 or sometimes 2 will be warm...very strange problem. I had every single part of the carbs apart and thought I did a really good job on them....just not sure where to look next? Once it's warmed up it runs perfectly at all RPM's and starts and idles just great.

just another thought....while I used the 26's, I took vacuum for the petcock off of the #2 intake boot since the 26's didn't have the vacuum nipple on the #3 cylinders like the 28's do. Don't know if any of that could make a difference...just trying to think what has changed...

The condition doesn't change though when the petcock is on prime.

Maybe the choke isn't working properly? Ed

79MKII wrote: ... still got a cold start problem. It only runs on one or two cylinders for the first 60-90 seconds and then the others just kick in. It's really hard to keep it running when I first start it.... seems like the air screws do very little to change the idle...can touch the pipes after its run for 30 seconds or so and only 1 or sometimes 2 will be warm....

seems like the air screws do very little to change the idle -- usually indicates something still wrong inside the carb, likely an imperfectly clean pilot circuit.

runs on one or two cylinders for the first 60-90 seconds and then the others just kick in -- Stone cold engine started and running for ten seconds should instantly vaporize water mist sprayed onto every exhaust header pipe.

Would assure that both the pilot circuit and enrichener circuit as perfectly as-new clean.




Starter -- ENRICHENER -- system

---

Would also assure visible fat blue sparks on every plug.

And assure all valve clearances are set to specs.

Good Fortune!

650ed....I was thinking that the choke circuit might have something to do with it. Those parts were some of the few not included in the rebuild kits.

Patton...Wow, you are a wealth of information! I guess I'll pull the carbs AGAIN and take a look. It's worth all the work to get it fixed. Those are great test prodecures and I will try them ASAP.

As thoroughly as I thought I had cleaned the carbs, when I had them off for my most recent float adjustment, I noticed that the accelerator pump wasn't working. I had rebuilt it with a new kit and checked each circit from the pump to the carbs individually and all were good / clear. I wondered if fuel was making it INTO the pump to start with. Sure enough, at the bottom of that float bowl, there is a tiny passage that allows the fuel into the pump diaphragm. It was plugged up and carb cleaner wouldn't clear it. I used some small wires and then carb cleaner and all 4 nozzles are now squirting perfectly! I'm hoping something like that is causing my cold start issue.

Thanks for all the help!

Well, I went through all of the carburetor checks and everything looks OK. Too bad...I was hoping to find something. I'll be reinstalling the carbs to see if anything I did helped. Maybe something was plugged and cleared up when I did the check?? I don't think so but I guess we'll see.

I'm not sure where else to turn. I guess I could put the 26's back on to make 100% sure that it's the carbs and not something else. It's just such a b!tch with that stock airbox.

I just looked over everything again and a light bulb went off. I didn't check the starter jet in the float bowl! I checked the whole starter circuit in the carb bodies but not the part in the float bowl... :blush: ...sure enough, all 4 were plugged up solid!

I was able to clear 2 of them but 2 are still plugged. I have tried carb cleaner, wires, and 100+ psi of air pressure with no luck so far. I'll let the carb cleaner soak for a while and if that doesn't work....I'll use the ultrasonic cleaner at work tomorrow. Hopefully that will clear these things up.

I'm sure that's the problem....those work with the starter circuit (choke) to supply fuel. No fuel, no run!! These are hard-learned lessons that I won't forget!

Thanks again Patton and 650ed!!

For reference, here's a pic of the inlet and the starter jet location on the float bowls:

looks like you might have a winner there! AND TWO MK11 Kwakas?!? Double winner in my book.
KT

Ktm181 wrote: looks like you might have a winner there! AND TWO MK11 Kwakas?!? Double winner in my book.
KT

I sure hope so! :woohoo: Yeah, my wife has mentioned something about me having 2 of them...although I don't think she used the word "lucky" ... :lol: