I'd load test the battery first. The 700's need a good battery or they can be hard starting. If all it needs is a new battery, I'd look for a different dealer. A service manual should have the procedure for testing the CDI. You should be able to download one from Country Cat. Even an older model 700 H1, should have that info. The 700 is a great motor, I have a 2014 700 TRV with almost 2,500 miles, only issue was original battery failed, it would turn over easily, but start hard. At least, a new battery solved my issue. Fingers crossed , that could be yours.
The engine turning over doesn't mean that there is enough in the battery to fire it up.
Most people here are speaking from experience. I'd either get your battery tested or try another battery if I were you.
Ez enough with a set of jumper cables. Just dont have the engine running on the donor vehicle. Yeah a sub par battery can cause engine stalling, erratic running, failure to start even if it sounds like its turning over fast enough. My 700 did this. Sometimes a spark plug goes south but that is more common on the suzook 700 rather than the H1. Your dealer??? If he doesnt have the proper diagnostic tools to test a CDI, then ??????
Often new atvs just sit at the dealer and without use the battery will go down. First thing after purchasing should be either a new battery or charging it. I got one from a dealer and after charging it got that battery to last about 3 years before I got a new one.
Even with a new battery, if I let my 700 TRV set for a couple weeks, last winter, it would turn over ok, maybe not as fast, but, if it started, often it would not idle right. Now that I use it almost every day, it's been fine. Wish Cat had made a place for a bigger battery. I was able to put a large Yellow Top on my 700 Diesel, which works awesome.