My Z1R carbs measure 28.8mm at intakes...??

I've heard of 'tolerances' but there's gotta be more to it here. I have what I thought were stock 1978 28mm Kz1000-D1 (the Z1R model) carbs.

- no accelerator pump (the 1980 Z1R *did* have 28mm carbs with accel pumps I believe)
- pilot air screw is on the side of each carb pointing up at an angle for easy adjustment



Well I measured the intake opening (engine side) i.d. of each of the 4 carbs and they all read 28.8mm


28.8mm is way closer to 29mm than it is to 28mm.

What's going on here?

Could they be a set of bored out 26s?

wireman wrote: Could they be a set of bored out 26s?

No, they look too clean, all the original manufacturing blemishes are there, and the tricky thing about the 1978 model year for the Kz1000 line is -- the Kz1000A (standard) and the Kz1000B (LTD version) came with 26mm carbs. The Kz1000D1 version (the one I have) came with 28mm carbs.

I suspect that if I had some in front of me, a Mikuni 26mm carb would likewise read 26mm+, I suspect that ol' man Mikuni was on a bender there and said "28mm, 28.8mm, what the hey, close enough for government work." As we all know, the Japanese government by way of MITI (Ministry of Trade) used Japanese taxpayer money to rebuild the Japanese economy by subsidizing the "big 4" and the car companies.

Old man Mikuni built great carbs, that's 100% obvious, but he fed at the government teet and now, here I sits, reading 28.8mm on my dang "28mm" Z1R carbs. Carbs funded by Japanese government subsidies.

He probably has karaoke and Benihana for breakfast.

You need to measure them where the slide meets the throat, not at either the intake bell or the exit bell.

I remember the first time I noticed 1015 stamped on a 1000 when I was a kid,I thought I tripped over something special! :woohoo:

gd4now wrote: You need to measure them where the slide meets the throat, not at either the intake bell or the exit bell.

Okay good deal, any recommendations on how to measure that deep in the carb? My caliper doesn't extend that long.

I found this at Harbor Freight.com but the arms don't look set up to measure bores, only parts that fit between the caliper arms:


www.harborfreight.com/6-long-reach-digital-calipers-60248.html

For my VM24s I cut out a 24mm piece of cardboard from a cereal box. measured & cut about as precise as possible & it fit inside the bore perfectly.

you need one that measures ID. & OD. something like this... checkout.payments.ebay.com/ws/eBayISAPI....actionId=-1&rsp=true

martin_csr wrote: For my VM24s I cut out a 24mm piece of cardboard from a cereal box. measured about as perfect as possible & it fit inside the bore perfectly.

Yep good deal there, that is my fallback plan right now. However I have seen those long-nose calipers. Can't find one on either Harbor Freight or Amazon. I love having the right tool.

Thanks there Martin.


Wireman if you got a free batch of 15cc then maybe I got a bonus .8mm of extra intake opening

I have an old set of manual calipers somewhat like the link pic that I use for this type of measurement.

www.amazon.com/Promax-MT79058P-Caliper-M...s=calipers+measuring

newOld_kz1000 wrote:

martin_csr wrote: For my VM24s I cut out a 24mm piece of cardboard from a cereal box. measured about as perfect as possible & it fit inside the bore perfectly.

Yep good deal there, that is my fallback plan right now. However I have seen those long-nose calipers. Can't find one on either Harbor Freight or Amazon. I love having the right tool.

Thanks there Martin.


Wireman if you got a free batch of 15cc then maybe I got a bonus .8mm of extra intake opening

The 77-80 kz1000s were all 1015,kawasaki just liked to round stuff off is my point. :laugh:

gd4now wrote: I have an old set of manual calipers somewhat like the link pic that I use for this type of measurement.

www.amazon.com/Promax-MT79058P-Caliper-M...s=calipers+measuring

Wow -- manual calipers -- thanks dude I have to get me one of those -- those have a lot more usefulness to measure in side bores -- thanks.