KZ440's with Mikuni VM carbs

For those who have done this conversion, how much of a difference in gas mileage is there?

I haven't finished the conversion yet, but I don't know if there will be a huge difference in mileage compared to a stock 440 if you keep the jetting that comes with the Mikunis.

BTW I'm assuming you're talking about VM30s that are pre-jetted for the KZ440 (like in the SpeedMotoCo kit) rather than 28s or 32s.

Nerdy wrote:

I haven't finished the conversion yet, but I don't know if there will be a huge difference in mileage compared to a stock 440 if you keep the jetting that comes with the Mikunis.

BTW I'm assuming you're talking about VM30s that are pre-jetted for the KZ440 (like in the SpeedMotoCo kit) rather than 28s or 32s.

I know there have been several conversions to those 3 sized carbs so I'd be interested in any of them, but with particular attention to the 30's for the reason you stated.  

It would be really nice if someone came up with a using a modern set of CV carbs too.  Several bikes I've owned that had jet kits made for stock setup, individual filters, modified stock airbox with a single, large filter that ditched the housing & they all worked.  Of course the newer CV's had quite a few differences compared to the ancient kz carbs.

28s would probably give you the best mileage but I haven't looked at prices or availability or anything.

30s would be the easiest conversion, as you've seen.

32s are too big for a stock KZ440. From what I've read, you would need a cam and head work for 32s to make sense on a 440 (and possibly not even then).

I'm going with velocity stacks (with light filtration) and short gearing and expect to be winding it up most of the time, so I went a little richer on the mains.

Here is a screenshot of a spreadsheet I did 6 years or so ago:

 

I'm a little late to the thread, but am currently debating between keeping the stock cv carbs or buying the speedmoto mikuni vm30 kit. I just don't know if the kit is worth the $430. Since you guys seem experienced with both what would you recommend I go with?

Hi id leave the stock carbs on unless they are unusable, if they were good enough for Kawasaki designers then why change? 

Originalretro wrote:

Hi id leave the stock carbs on unless they are unusable, if they were good enough for Kawasaki designers then why change? 

Agree.  Changing the carbs will be expensive, and there is no guarantee that they will run properly out of the box.  

Confucius he say if it aint broke dont fix it