Z1000 A1 1977 bored to 1105 Carb Jetting

Hi all, I picked up a 1977 Z1000 A1 here in Australia last year and have restored it. The engine was tired and needed reboring so went to 1105. During the rebuild I have found lots of answers to questions on this site so thanks to all.

Her is where i am at, I have had a little trouble getting it to run nice, idles OK and runs really well over 3000 rpm, between 2000 & 3000 I get a little hesitancy in the acceleration.

Carbs are VM26SS stamped ith I.D Z12 00, thouroughly cleaned, float levels set via wet method to 3mm, bench sync then vacuum sync. The carbs came with the following setup;
112.5R - Main Jet
17.5 - Pilot
Needle Jet - I cant read any identifying numbers?
Jet Needle - 5DL31-5 with the clip on the bottom, 5th position
Standard airbox but without the air box silencer
Yoshi 4 into 1
DYNA-S

My carb knowledge (average) leads me to think pilot jet/air jet screw setting as the hesitancy is only between 2 to 3000 and 1/8 throttle opening?

Any replies appreciated

Regards Richard

Could try enrichening the pilot circuit.

If carbs have side located pilot air screws, enrich by turning in clockwise (which reduces air).

If carbs have bottom located pilot mixture screws, enrich by turning out counter-clockwise (which adds mixture).


Good Fortune!

It has the air screws on the side, I tried screwing them in and tested at a few differnt richer settings, seemed to make the hesitancy start as soon as the throttle moved off closed, OK around 2500 rpm and above. Regards Richard

Make your life a whole lot simpler and put a filter, stock or K&N, in the stock airbox. From there with your carbs id try 115 mains, the pilots you have, start with 1 clip up from center, maybe 3 turns out on the adjusting screws. That's will get you in the ball park, minor changes from there will get them dialed him. Balance the carbs also. If the adjusters need to go past 4 turns then go up to 20 pilots. Just my opinion, my bike is close to yours, just some head work and cams