Boring out my 26mm mikuni carbs to 29mm

[Warren]

Vm26mm boring out to 29mm

Here is the write up on this.

[Warren]

Vm26mm boring out to 29mm

Here is a pic of the inside recess bore where the slide seats. From what it looks like you need to mill this inside ID down so so the slide will seat below the intake ID that you machined to the 29mm diameter.

[azr]

ahhhhhh.....it looks as though from the article you posted this mod will give some extra performance but nothing like a proper set of 29mm's.

[Warren]

Vm26mm boring out to 29mm

Here is a pic of the intake side of the carb that will be machined out to 29mm. Looking at both photos you can better understand how the material gets pushed down into where the slide seats.

[Warren]

Vm26mm boring out to 29mm

Yes and no, you get the performance gain, but loose on the gas-mileage. Ether way you loose due to the cost of the 29mm. As for the gas Mileage you will have already lost that anyways if you have installed a 4 into one with pod filters and you have re jetted your carb. So for me if it's a performance gain it's a improvement all around. That's why I think they did this in Super sport. As the gas mileage was already gone with all the performance up grades they made. So for them to run the 29mm up grade it did not make a lot of sense as they would not gain anything from it. I maybe wrong, but this is what I am getting from this info.

Cheers,

[Agemax]

The reason why you have to machine the recess for the slide is because otherwise the slide cutaway will be too high. You can get around this in 3 ways.. 1) machine the recess deeper by 1mm. 2) machine off the bottom of the slide and reshape the cutaway, or 3) buy new slides with higher cutaways.

I have researched this mod extensively and concluded it is financially not worth it as you can buy 28's easily and cheaply and they do the same job, or for slightly more money you can buy the VM29SS flatslides and easily bore those out to 33's if you wish.

By the way, the 28's are only 26's bored out at the factory anyway.....

[Warren]

What did the vm28mm come stock on? I've have yet seen these carbs. I have searched these on eBay and there are no carbs in this size for 4 strock engines. Am I missing something?

[Agemax]

They came standard on UK spec GS1000S and N models. I have 3 sets of them myself

[Warren]

I don't think these carbs are easily available in North America. If they were I'm sure the 28mm would be the best option as you stated.

[chuck hahn]

The way I read it was that the "alternative" to machining them would to just simply buy a set of factory 29s. What they are saying is that its just easier to buy new 29s and that the mod is actually very compataile to stock 29s.

Also, i thought it said the 29s ( and this mod ) would provide an INCREASE of around 3 miles per gallon in mileage.

[chuck hahn]

Heres a set of Kawasaki 28 MM pumpers. Take off the pumper bowls and linkage and cap off the cross over tubes. Put on VM26 bowls and your good to go. Or leave them as pumpers if you wish. Should bolt up without any problems.

http://www.ebay.com/itm/KAWASAKI-KZ900-KZ-900-KZ-1000-KZ1000-MIKUNI-CARBURETORS-28mm-10-K20-/321502973779?pt=Motorcycles_Parts_Accessories&hash=item4adb120f53&vxp=mtr

[Warren]

Today I started cleaning my 26mm carb bodies and would like to know if the brass insert where the needle goes through into the main jet, is this pressed in or threaded? I will need to remove this before machining and I do not want to damage it.

[chuck hahn]

Press fitted and the emulsion tube holds it up there. gently use the end of a tooth brush handle and tap it out the bottom. By the way, thats the air jet. Look at it closly. Some have the back side cut away. Be sure of how they are set in before removing.

[Warren]

Awesome thanks for the tip!

[chuck hahn]

Or is it the needle jet??? Anywho..it does come out like i said. LOL