rejetting 1980 kz1000 ltd (way too lean-i think)

hi, just got ignition system sorted, now for sorting out the mix, im running k&n type filters and a 4-1 marshall exhaust with mikuni vm33a carbs.
i have all the standard setup data and am expecting them to be running lean with my free flowing system.
the bike runs well at low revs but when the carbs are opened up or its revved above 5000 rpm it misses, backfires and boggs badly.
on taking carbs apart ive found correct cutaway, correct needle but on fifth notch not forth (ive put it back to forth for now), most shockingly ive found that the mains are 115 when the standard setup should be 127.5
so im way leaner than even the stock system.

wondering now what size mains i should go up to as a starting point considering they should be 127.5 stock not 115. does anybody else have a z1000 with vm33's running 4-1 and kn filters- if so what size mains and what needle clip position do you use... cheers

have a 78 ltd1000..running dyna-s ign...accel super coils and wires..mac 4-1...open can...only 26 carbs...but my jet kit calls for runninf 140 mains...i'd say you defenitly need to go up on the mains...mine had same problem before jetting..

sorry...didn't see the 1000cc in original post..

cheers brian, still thinking someone must be running a similar system to mine: z1000 ltd, vm33 carbs, marshall 4-1 pipe and K&N type filters- what size mains do you use, and what needle clip position (6DJ30),
if not then any tips on what size main jet to start on above the stock size (127.5) would be a help, cheers - mat
god only knows why someones fitted 115 mains in mine and raised the needle to compensate for mid range weak mix, was meant to have been proffessionaly set up - ha !

Matty... there is a lot of info on doing plug chops on this site. Do a search. You need to buy some #127.5 mains and go out and do a plug chop. The #115s are WAY too small for those carburetors. NEXT thing will be to make sure that your petcock, fuel filter or gas hose don't become your main jet. Make sure your petcock can flow sufficient gas. Use a hi flow type Pingel and use 5/16" gas hose with a high flowing filter.

I am not sure where you will end up but I am guessing about #132.5 or #135 mains on those things but again, a plug chop is in order.... if you can get the thing wide open on #127.5s with the pods and aftermarket pipes.