My 4000 mile V7 generally runs great. Occasionally when on a constant throttle at about 50 to 60 mph its as if the kill switch has been flicked off and on very quickly. Describing it as a flat spot isn’t quite accurate as it seems a bit more dramatic than a flat spot. Seems to be worse in warmer weather but can catch me out out at any time. I’ve read the posts about the tank vacuum issue but this seems slightly different to the descriptions of that fault. I intend to have the bike serviced in spring and hope the dealer can address the issue but wonder if there are any theories out there ?
I had the same issue with mine. Recently I bit the bullet and remapped it with UpMap. Worth every penny. The bike now runs smoothly, as it should have when it came from the factory. The original mapping is a disgrace. The UpMap is perfick.
Obviously I defer to those on the forum with far greater brand/engineering/electronics knowledge than me, however, I experienced symptoms extremely similar to those you describe on an XT600E I owned. It was almost a violent, intermittent, momentary interruption of ignition. I tried all sorts, new plug, new coil, new ecu. The bike was looked at by Yamaha and independent technicians to no avail. I was going to replace the stator next as, due to a lack of core skills, parts cannon seemed my only option. Before ordering and whilst prodding around the wiring randomly with the bike running, I caused the fault to reoccur. It was a cracked wire to the ecu. Duly repaired, the fault never happened again. I’m not saying this is your issue but, you never know!
Also, on the same lines but from a KTM perspective, a faulty sidestand switch also has a similar effect, eventually getting to the point where the bike stops completely.
So it’s a 2021 V7, I’ve got a 2021 V7 850, have had very similar symptoms but with me usually riding 40 - 50 mph -ish after a cold start ….
I disabled the EVAP, never happened again.
Cut and block the hose with the solenoid valve behind front of left side panel. Cut below the valve and leave in situ, I stuffed a M8 bolt up it to block the hose (leave enough length of hose to do it!).
There’s another similar sized hose that does the actual tank venting and goes to the EVAP canister, to get ‘normal’ tank venting to the open air, I just cut a slot in it (sort of half cut through then) just to relieve pressure. I never bothered removing the EVAP canister itself, but I can understand how just leaving it there could get on other people’s nerves.
HTH
Not my photo but from advrider.com, note hose at front is just cut and left open (tank vent). In this case the lower valve spigot connector has a pipe cap over it.
The hesitation in a constant throttle at around 3-3.5k revs was well known when the earlier bikes came out e.g.2021/22 (felt like it was running out of fuel). The sensation disappeared as soon as you opened the throttle up, even slightly, but it was really annoying and disconcerting. There was a revised factory map which should have been applied at the first service by the dealer, but some didn’t seem to get it done and a few dealers denied any knowledge of it from posts I saw at the time.
Mine WAS done and it cured the issue as well as bringing the average fuel consumption readout back in the real world. The latter would read 74 mpg when calculated figures from a brim full tank gave nearer 57 mpg. Incidentally, this has improved with milage to the point I rarely get less than 61-63 mpg.
