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Hello all could do with some help pleases. Building a cafe racer kz650 with Mikuni kogyo carbs. Theses have been sent off and Vapor blasted and rebuilt all new parts.
Engine has been rebuilt all new bolts and gaskets and bits new plugs new running on munit new coils dyno . compression test done. On warm 1.155 2.150 3.158 4.160.
Carbs main jets are 112.5 and the pilot, jet is 17.5 . The bike starts on choke when warm choke of open throttle then she dies. Every time. This was a barn find so never 
had any jets in this . I jut put theses in. Don’t no where to go go on the sizeing if this is the problem . Losing my head. Photos and video to show .could do with a lot of help sorry.

You need ALL carbs settings stock.
Make sure all the jets are genuine MIKUNI and not "kit" parts ..
Fit air corrector jets and go up a size from stock on the mains.
Air corrector jet kit.Kawasaki Z1,Z650,Z900,Z1000,Z1R.MK2, MIKUNI.LEDAR.PODS.K&N | eBay
What pods are those ?
If they are cheap Chinese, Emgo,Hi Level , DNA etc or no name brand then throw them in the bin and fit good quality free flowing K&N, Ram Air, S&B, Unifilter and you should be good to go..

Hi thanks. Yes the carbs are set to stock. Mikuni jets are from Allen performance.com. Will look into the pods.
Do have air correctors but didn’t no what side to put them on as it look like all for carbs at 4 o’clock. And on other page 8 o’clock don’t no. Any one No ? Are the main jet size right.
needle is on clip 4 .

Harris1975 wrote:

Hi thanks. Yes the carbs are set to stock. Mikuni jets are from Allen performance.com. Will look into the pods.
Do have air correctors but didn’t no what side to put them on as it look like all for carbs at 4 o’clock. And on other page 8 o’clock don’t no. Any one No ? Are the main jet size right.
needle is on clip 4 .

See attached pic for the correct jet positions highlighted in white for your VM24's.
It's only CV carbs that have them all in the 4 o clock position.
 

Ok the carbs you posted a pic of appear to have only an air screw (no pilot screw or both) so I am assuming they are vm24ss carbs and not vm22ss carbs. They also do not have a vacuum port on carb #2 so are from before 1979 as I understand it. So in that case they would of come stock with a 102.5 main and 15 pilot jets. There were some changes in needle and needle jets and the size of the cutaway on the slide between the set of carbs that fall within the time span.

If you post the ID stamped on the carbs (see attached) I may be able to provide more info for you.

Hi thanks. Right have taken carbs of the number on the side is V6801 have uploaded photos .also have put in the Air correctors in now . Put back to stock 15 pilot jet. Waiting for brand new main jets 105.  And  needle back to clip 3 y63 is this right to get this running properly…..thanks

I do not mean to confuse anyone. but the Y63 needle is not a stock needle, rather an aftermarket one. I do not know what if any differences there maybe between it and stock needles. To the best of my knowledge there were a couple of different needles and needle jet combos used on the air screw only vm24ss carbs from 77 and 78.  Some of the needles are set to the 3 slot and some to the 4th slot. Not sure if any of this will make any big issues or not. Just wanted to make sure you know there were differences.

A bit obvious I know but you are sure that the multiple holes in the emulsion tubes that the main jet screws into are 100% clear.
It's no coincidence that it bogs at the point of transition to include main jet and before needle jet revs. 

Hi right i have taken the carbs off. Cleaned and changed the pilot jet back to stock 15
Main jet back to stock 105. Put all back in started bike.And this was 100% worse than ever. Wouldn’t idel and when touching the throttle would die evertime.
So theses setting are no good i think. Seems i am going back wards on this . What next?

What kind of advance for the ignition are you using? What do your plugs look like? If the plugs are good it might be the advance curve.

A lot of things got wiggled around when you remove and install carbs.

When I was a teenager I was having a similar problem with an IT200. My stepdad traced it to one wire loose in one bullet connector.

So, check every single wire, every single ground, every single connection.

Can’t hurt.

Hi thanks. The plugs look ok .i think a bit lean on the plugs. And for the advance, I am running brand new.Dynatek  Dynamo s Ignition system with coils. 
But still opens the throttle and dies. What should i do the timings look ok.?