Cutaway vm28

Hi everyone, I changed my Needle Jet in my vm28 to corrige my rich low transition, I keep my 5cn15(they look good, no scratches). Now I have the same problem. Rich until 3/8 throttle to achieve 13 afr wot. What do you think about replace Cutaway valve could do in that case ?! I have now 1.75 cutaway.  Thank youu

A larger slide cutaway will mainly lean off 1/8th to 1/4 throttle.
You may need to fit bigger pilots once you change the slides.

Ok so thats not my problem!! 13.5 afr on idle and when I touch the throttle it drops to 10.5 afr!!!

10.5:1 is very rich. Perhaps the larger cutaways are what you need.

Where do I can find cutaway?!!what bikes?

This is from the Sudco Mikuni Manual :

 

You have to take a slide out of your carbs and measure it, then see what may work. There are several OEM Kawasaki slides on that list.

Suzuki also used Mikuni, but unless someone with more knowledge on Suzuki carb spares speaks up that may be more of a gamble. I am not sure why only Kawasaki is on that list.

Mikuni quantify the cutaway size as fuel flow VS throttle setting.

 
 

I have 1.75 cutaways write on them!  Do the 2.0 can make a great difference or probably just raise my 10.5 to 11:5 ?!

Maxbou92 wrote:

I have 1.75 cutaways write on them!  Do the 2.0 can make a great difference or probably just raise my 10.5 to 11:5 ?!




 

Mikuni is showing the % difference in fuel flow (wet state) VS throttle setting so it would be hard to express the same thing in AFR (burned gases)

It would be hard to tell what kind of difference that would make.

Measure the slide first and see what you have to work with off that list and how much its going to cost. Those slides might end up to be $50 each if you can find them.

How is the bike running now?  Can you notice when its rich?

 

It burbles at 1/8-1/4 !! Wideband show 9.75-10.5 constantly at that point !! Should I do a test without Air correctors ?

I just did a quick search on that Mikuni VM28 part number but it is only offered for individual bodied carbs with the idle slot - not the one you need.

I did find one listing on Ebay for the early Z1 (search vm28/210) at 3.0 cutaway ($42 Can each) but he only have 3.

Yes thats what I found !! Thank youu very much

wrote:

Yes thats what I found !! Thank youu very much

Maybe someone on here might have spare slides at 2.0? That 1.75 was a custom part for the bike model tuning which can vary by model or year.

Just found this stuff :

 

 

See some 28's at 2.0 and 2.5 cutaway.

I don't see any Kawi 28's at 1.75? Is it possible you have some Suzuki carbs? Maybe off a 750?