smoothe bores

[mick12]

once again i am trying this i cant upload pics as they are to frigen big and i am stuffed if i can resize them i have what i think is a set of 29mm mikuni smoothe bores firstly how do you id them secondly in the throat in front of the slides is a needle that protrudes very slightly it is adjustable from underneath and infront of the float bowls what is it for i have no experiance with old carbs so any info would be apreciated instructions on how to resize pics would be good too

[dickfaber]

as for photos, open a photobucket account http://www.photbucket.com and upload the photos there. then get the img link from photobucket to put in your post. the link looks like "

[mick12]

ok images lets see if im doing it right http://i272.photobucket.com/albums/jj19 ... CF1069.jpg and the next one http://i272.photobucket.com/albums/jj19 ... CF1068.jpg seems to be working

[Jonno]

Mick,

Click on the quote button and you will see the tags on each end of that link... things.

ok images lets see if im doing it right and the next one seems to be working

[z900/zx9]

Pretty sure there standard carbs,see if Gos comes along but thats what i reckon

[s man]

Standard 28mm Z1 carbs I think. The Z900 had 26mm..

[z900/zx9]

I agree that they are 26mm carbs as the earlier 28 mm carbs had a flatter top cap

[mick12]

Ok so we say they ar not smoothies[ no biggie ] what is the needle in the front throat for and what is supposed to happen when it is adjusted one way or the other if i know this i might be able to tune them properly

[z900/zx9]

Best to start with a set of vacum guages before u start playing with needles,normally this will make a huge difference.

[mick12]

after taking the carbies off i have found the floats are in both ways 2 floats are in with the larger portion of the float upward and 2 downward all float tabs have needle marks on both sides which tells me that they have been stuffed with quite a bit and put back wrong so anyone know which way is correct

[Gosling1]

....Ok so we say they ar not smoothies[ no biggie ] what is the needle in the front throat for and what is supposed to happen when it is adjusted one way or the other if i know this i might be able to tune them properly.....

It's a biggie alright - if they are smooth-bore carbs these are far better performance carbs than stocker 26 or 28mm Mikunis. Easy enough to find out - just remove the airbox boots and pull the carbs off ( you will need to do this to sort the dodgy floats anyway) - then lift the slides and look down the carbie bore......smoothbore carbs have thin slots in the walls where the slide moves up and down, stocker carbs have a big cutaway to suit the solid slides used in normal carbs. Smoothbore carbs flow way better than OEM style carbs....

I probably should do some close-up photos of both types and have this listed in a sticky at the top of this forum.......

The larger portion of the float should point downward. Have a good look at the needle & seat as well, in each bowl. These may need replacing. Get your carbie bits at Z1 Enterprises in the US. Keyster kits are what you need.

That tiny needle at the front of the carbie is the mixture screw, and it should not be protruding at all. If it is, then it is screwed in too far and the setting is way rich. The standard starting point for these mixture screws is about 1.5 turns out from fully screwed in. You start at this position and then adjust in small increments (I normally do 1/8 turn at a time) to get these correct.

I have a question for you though - what bike are these old carbs fitted to ?? It looks like a late-model motor of some type ?

[kawadave]

I have a question for you though - what bike are these old carbs fitted to ?? It looks like a late-model motor of some type ?

Looks like a snoozooky GSX?

[mick12]

kawadave is nearly right they are currently mounted on an 85 gsxr 750 and are probably the best part of it at the moment

[Gosling1]

slabby gixxer 7fiddy eh ? that is an interesting motor for someone to bolt up some old 26mm slide carbs to !! I am pretty sure that the 85 slabbies had 29mm flatslides ? If you had some 29mm smoothbore Mikunis these would actually work pretty well on that motor I reckon

[mick12]

ok have some more photos and where exactly are carbs measured to define their size[ http://i272.photobucket.com/albums/jj19 ... CF1084.jpg] [ http://i272.photobucket.com/albums/jj19 ... CF1076.jpg ] [ http://i272.photobucket.com/albums/jj19 ... CF1076.jpg ] [ http://i272.photobucket.com/albums/jj19 ... CF1073.jpg ] [ http://i272.photobucket.com/albums/jj19 ... CF1075.jpg ] [ http://i272.photobucket.com/albums/jj19 ... CF1089.jpg ] [ http://i272.photobucket.com/albums/jj19 ... titled.jpg ] the photo of the floats shows how twisted they are no bloody wonder they were pissin fuel and to gos are they the right way over because if the go the other way float level measured 40 mm also throat measures 29mm across