Cylinders 1 & 4 are fired by the same coil, so the problem is on that side. Which sparkplugs are you using? Are the secondary wires and caps in good shape? Connections to the coil clean and snug?
You should measure all of the valves and write down what you find. You will then need to pull the adjustment shims out of each valve that is out of spec. Pull them out one at a time, and write down the thickness of the shim. At this point you will have two numbers for each valve that is out of range. The factory shims have the thickness printed on one side, but I recommend measuring each one to be sure. With those two numbers, you can calculate how much thinner the shim needs to be. You may be able to shift some shims around to get where you need to be, and then you will know which shims to buy. A shim kit with a variety of sizes will save quite a bit of time, though there may be some sizes that you never use.
since you have a 750, the cams will have to be removed to get to the shims. Read the procedure in the manual several times, and ask lots of questions here. The procedure is described on pages 12-14. The text on those pages is perfectly clear in the link I posted. The pictures are not great, but I am sure you can figure it out. If not, just post a question here.