74 Z1 Which carbs, which jets?

I am looking for advice based on experience with the following combo. I am boring my 74 900 to 1015. I have pods and a 4 into 1 ( that is on the left side). I have the original 28s and a set of 29s. I will be using stock cams, ignition, and mild porting.
Which carbs with what size jets are commonly used? I live in western Ky so altitude is not an issue and most riding will be cruising country roads around 55mph. I hope this is enough info, thanks in advance. Dennis

The original Z1A carbs are a bit of a pain to tune but if tuned properly, will provide all the gas a stock bike like yours can use for the most part.... they will fall off a little in horsepower compared to the VM29s at about 7000-7500 rpm where the smoothbores are able to flow more air/fuel. The 29s have a few drawbacks, as far as tuning (a bit tricky) but when set up, hold their tune well. Either set is more than adequate for putting around at 55mph. If you are not a boy-racer type, I doubt you will notice much difference in normal driving conditions.

Thanks for the reply, Any reccomendations for jet size for this set up. The 28s have 112.5 main and 17.5 pilot, the 29s have 120 main and I'm not sure about the pilot, 25 best I can tell. No I'm not a racer type.

Post edited by: dnhnky, at: 2007/04/04 15:10

I am not sure you have Z1A VM28s if you have #17.5 pilot jets... all the pilots for those things are #20s... they are a different style jet than the 75 Z1B carbs which used #17.5 pilots. Do the 28s have 17mm drain plugs on the bowl? The stock jetting for a Z1A carb will work OK with pods and pipes but you might want to bump the mains a tad... to #120 or so. The VM29s... #120 mains. 5Dl31-3 (clip jet needle to 3rd slot) and #17.5 pilots. The 29s should be 1.5 slide cut outs to take advantage of this jetting. If you have a set from another application, the slide cut out may be larger and require a larger pilot jet because airflow is greater but slower. The slide cut out is stamped onto the top of the slide and will be 1.5 or 2.0 or 2.5 I think. Most smoothies on Kaws are 1.5. with 1.5 slide cut outs and 17.5 pilots, turn air screws out 1/2 turn from lightly seated.

Post edited by: wiredgeorge, at: 2007/04/04 15:38

I just double checked the 28s and the jets are 112.5 and 17.5. I was given this bike by a fellow soldier and he could have been stationed somewhere in a high altitude. Once he got here(in Kentucky) it was too lean that could explain the set of 29s that I got with it. He also had velocity stacks on it. If the carb i.d. on the Z-1 Enterprises page is correct I have the late Z-1A carbs because there is a regular screw on the bottom of the fuel bowl. I don't know which carbs he was running on it because everything was in boxes. Also the 29s are 1.5s.
I was looking for general idea of where to start for the mods I have. Thanks for your help.

Start with 28s... "regular screw"... do you mean a 6mm drain screw on the bowl? If so, they are not Z1A... they are Z1B. Id mark on flange will be 2170. I have already mentioned which jetting is appropriate for both the Z1B 28s and 29s.

I did mean the 6mm drain screw for the fuel bowl. Thanks for the advice.