TOPIC:

I just got a set of carbs from a 76 kz900 measure 28.575.There are no pilot jet adjustment (on bottom by float bowl)as do the cabs i have on my bike do now. am i going to have any tuning problems as this is throwing me a curve ball on this now.

Post edited by: rammy, at: 2006/02/22 14:03

Are you measuring the I.D. of the engine side of the carb when you arrive at 28.575mm? What is the picture of?

The carburetors you measured are VM28 carburetors. The 1976 KZ900A4 came with VM26SC carburetors which measure 26.7mm at the ID of the cylinder head venturi. I am not sure what the heck that picture is supposed to show but you should probably clean it. You will NOT be able to tune the 28mm carbs UNTIL you have identified them as 28mm carburetors varied GREATLY in terms of internal components; especially jetting... anything from a #102.5 main jet to a #125 main jet... where would you start tuning and baselining unless you know which VM28 you own.

The picture shows where the pilot fuel screw is located on some of the VM series carbs. (engine side,on the bottom, protruding through the float bowl). Most of the VM series have this protrusion,some do not use it. If you spray some carb cleaner in the hole, does it make its way to the intake tract? If not, the carbs have only the pilot air screw (located on the side,commonly refered to as the idle mixture screw) to adjust the pilot system.
Post a pic of your carbs. This will make any questions you have easier to answer.
Fish

I remeasured the carbs and they are 26mm.(the ruler threw me a curve ball) used the proper tool this time.Hope this picture helps clear things up.

Post edited by: rammy, at: 2006/02/23 12:36

having probs uploading picture

Post edited by: rammy, at: 2006/02/23 12:42

here we go again

Try making the picture a little smaller before you upload.

Try spraying some carb cleaner through the hole pictured. If it doesnt spray through to the intake tract, then it was not meant to have the pilot fuel screw. The carbs were made both ways (1-with both pilot fuel and air screws/ 2-with only the pilot air screw). The differences in the different carbs is usually compensated for with the pilot jet that is inside the carb.
The VM26 carbs were used on alot of bikes (GS 750, KZ 900 and others) and have suble differences between them.
I suggest getting a shop manual and cleaning the carbs. The manual will probably show the differences in the 2 carb sets that you have.

Fish