carburettor problems

I hope somebody can help me. I have a 1982 Z750 L1 4 cylinder with a carburettor problem. I purchased the bike in boxes, and totally rebuilt the machine. The bike has a Harris 4/1 exhaust and K&N air filters.I have put in 110 main jets back in the Mikuni carburettors which i belive is standard and restricted the air flow of the K&N (sponges inside each of the filters with gauze)it is the only way i can get the machine to start and run.The problem i am having is for some strange reason the bike once the engine has been revved past quarter throtle and closed the engine will continue to rev upto 7000 revs and stay there. If i use the kill switch untill the engine comes down to 2000 revs and switch it back on the bike will then tick over as normal.I have replaced the inlet rubber hoses and i am sure i do not have an air leak between the carburettor and the cylinder.Has anybody got any suggestions, many thanks mrsj

mrsj wrote:

Has anybody got any suggestions, many thanks mrsj

Put the stock airbox back on and avoid the misery that comes with jetting pods.

make sure you don't have a vacuum leak somewhere else like a goofy line to the percock or some other line that's open.

Thanks for the reply. Unfortunally I dont have the stock airbox, and I dont think i will be able to get one now. I will look to see if there are any vacuum leaks,Although there is only one vacuum pipe that goes to the fuel tank which holds the fuel tap open, the other three carburettors are sealed. Thanks again. mrsj

When my 750 did the same thing it scared the piss out of me. Found out that my vacuum line that went to #4 carb had popped off. You might want to check and see if the other three carb plugs have a good seal.

Not that it happened to me, but another cause for what you are experiencing is too tight a throttle cable. I'd make sure you have at least 1-2 mm of slack in the cable and that it will snap back all the way when you cut back on the throttle.

Good Luck!