Hey mike. That bike should have plenty of power for your wife and for you! My guess is it’s just a matter of cleaning the carburetor better and tuning it the right way. I would do that and double check the air intake box for any nests or behaves or blockages. As far as the exhaust I’m assuming it’s clear and nothing is obstructing it. Get yourself a good can of carb cleaner with red tube on the nozzle to get inside the small holes. A can of compressed air with the same red tube and a set of cleaning tips from amazon. Remove the carburetor and set yourself up a nice clean area to work. Take it all apart and take your time. Ask as many questions as you want and post pics if need be. Once that’s all done and you dial in that air/fuel screw my guess is that she will run like a champ! When it comes time to dial in the air/fuel screw let us know. Talk you right trough it. Throw a fresh spark plug in as well. No need for adding a better exhaust, re-jetting etc. Sumind Carburetors Carbon Dirt Jet Remove Cleaner, Includes 13 Wire Torch Tip Cleaner Tool, 20 Cleaning Needles and 10 Nylon Brushes Tool Kit for Motorcycle ATV Moped Welder Carb https://www.amazon.com/dp/B07KQYWGGD/ref=cm_sw_r_cp_api_i_wdhsDb48SW7AV

Closest I could find is for the 1998 454 service manual located here: See if that work for you Mike

Suggestions. go back to basics. check the compression, spark, if the compression is not right the start there, find out why. Check the valve clearance's, check timing. if all that's not right it doesn't matter about everything else. One thing I have found through out the years on spark plugs is, if the item is a Japanese type import use nepond denso or NGK plugs only. Champion spark plugs don't play well in them. Yet champion plays well in small lawn and garden equipment. I had a Yamaha bike that had two spark plugs holes. Put brand new champions in it and it wouldn't run for nothing, put an old worn out ngk in it and it ran, Put a champion in one and ngk in the other and the ngk worked with out any problems, Champion didn't run at all. Tried more than one and from different vendors too. That is just one instance I've had among many, so that's why i say that about spark plugs. If all that's good then move to the fuel side of things, Suzuki uses vacuum operated fuel pumps and in some a vacuum operated fuel petcocks. A leaking diaphragm in any of those can dump fuel straight into the engine. Making you think the carb is the issue. Clamp off the lines, check for fuel in the lines. I do see these items fail more than you think, more so on the older atvs. Trash getting to and into the fuel pumps kills the diaphragms. Once you get it to run, change the oil before you test ride it. the gas will damage the bearings and the centrifugal clutch. . Oil is cheap compared to the damage. Hope some or all of this helps.