TOPIC:

I Was wondering if any of you can identify the years for these (both came off of 650's) and what the differences are in terms of performance.



and these...



Also, what is the part circled in red on the bottom of the second carb setup?



How do these compare to the stock 77' KZ 650 carbs? I've also got a set of those off of one of my bikes, but it has almost NO adjustability... I'm assuming due to emissions?

Which of these carbs is the better "performer" I guess is what I need to know.

Thanks!

the second set has an accelerator pump. when you crack the throttle hard if gives a little squirt of gas to richen the A/F mixture for that split second.
Scott

Hey caffcruiser. My guess on the carbs are Mikuni 24's. Scott seems to be correct on the accelerator pump option. If I am not mistaken they are off later year 650 models.

Cheers-Colin Firth-Ontario Canada
1977Kz650 Custom -810 big bore with lottsa go-fast goodies tucked away inside.

The accel pump is there to help cover the EPA's increasing lean jettings tendency toward bogging upon cracking the throttle. The first pic is the 1st gen 650 carbs, from '79 on they used the pumper carbs. My B2's carbs are like the first pics

The guys have already summed it up pretty well. The first set of carbs pictured are 77-78 model year. Can't tell by your picture, but some of them would be airscrew type, with the idle mixture adjustment on the rear upper part of each carb. These were used in 1978. In 1977 They used the pilot screw type, with the mixture adjustment a screw on the bottom front of each carb. This is where the confusion sets in. Some 1978 use the pilot screw type, some the airscrew type, and some actually had both. Quite a variation in 1978 to try to cope with emissions. The performance of the 650s never improved on the 1977 models. They were the best running KZ650 off the assembly line.

Thanks for the replies guys!

Now for the next question.... will the non pump carbs be enough for a 650 taken out to like 800cc's?

you will probably lose a lot of potential top end sticking with the 24's if you get the 810(or similar sized) kit(I believe MTC used to make a 780cc 12:1 compression kit, Is that what you have? I remember you saying you might need to run race gas...). however smaller carbs have better throttle response down in the lower RPM's. But my guess is that if you are getting a big bore kit, you like to drive hard and like to keep it revved up anyway though right? So go bigger if thats the case. Colin is using 28's on his 810cc 650, and I will be also. If possible get the rare 29's make sure to port match the intakes if you go to larger carbs to get the most out of the upgrade. larger valves and cams and a good pipe also optimise power. just doing one upgrade wont do much, its a combo that makes a bike a beast:evil:
Scott