Modern Buddy

Almost exactly after six miles of riding, my 2013 170i feels like it "hits the governor" for two seconds, every few seconds. I basically get a slow-motion loss of power that cuts in and out, very rhythmically. After nine miles or so, it starts affecting my top speed by 2-3 mph.
I first noticed it at WOT about four months ago. I ran some fuel injector cleaner through the engine, then changed the oil making sure to not overfill it, then I just changed the trans fluid, again being very careful to not overfill it. It is still happening, and now I can notice it at lower speeds, down to about 50 mph (~3/4 throttle?) I verified it does this in no-wind, with a full tank of gas.
It reminds me of the feeling I'd get in my motorhome, when the auxiliary fuel tank pump would go out, like the engine is starving for fuel.
Ideas?

It may not be the fuel system. Check your spark plug cap, spark plug wire where it screws into the cap, where it screws into the coil and check the sheath for any cuts or abrasions. Then check that the connections from the ground and CDI to the coil are good.

I'd hope that PGO has solved it, but the Buddy line has manifested some cases in the past where the stator fails, causing this sort of behavior. I do hope it's not this, but keep it in mind if the coil and wire are good but the issue worsens.

I just started thinking that I should check the spark, since like I said, it feels like I have hit an rpm governor, like the engine is not getting full power from the fuel/air mix. I'll get into it tomorrow night, thanks.

If it runs fine for 9 miles before the problem, heat is causing an issue. I've had coils and cdi pick up sensors on some other bikes I've owned.. Hope you don't get stranded!
The other time I had a similar problem, it was sediment in the fuel filter.

The folks above have given you lots of good ideas. Does the 170i have a fuel filter? I can't remember. If yours has one, I would take a look at it, too.

One other thing, if all else fails, service your CVT. There are a few threads on this board where weird power-loss problems eventually were traced back to bad rollers with flat spots on them. I know this isn't a perfect match to this situation owing to the power-on/power-off thing, but it's still worth a shot.

When you figure this out, please update this thread. I was just searching through our archives and found a bunch of open-ended threads where folks had strange loss-of-power problems but they never reported the solution.

Good luck!

My 170i does the same thing. It feels like it's cutting out at ~60 MPH after ~5-7 miles and once cut out altogether for about 2 seconds.
My scoot' has ~4,400 miles and has an Iridium plug. It really feels like a rev' limiter cutting in...

I took a break from riding, forgot about this and didn't ride on open highways for awhile, so didn't really notice the problem.

Rode to work this week and noticed the surging was gone. My top speed has dropped a bit, maybe 1-2 BMPH, speedo rarely reaches 70 any more.

I checked the plug (tawny deposits, maybe a bit lean).
I checked the spark (bright yellow. Sad little plug, probably should upgrade).
I checked the filter (filthy and puny, bought a car filter and opened up the hole, so now I have drop-in filters for $3 a pop). I did notice a big improvement in acceleration, but I'm not sure if this improved the surge problem.
I tried checking the fuel filter (couldn't find it.)

I continued to run fuel injector cleaner, mostly used Lucas Fuel Saver every other tank. I think this maybe did it because the few times I did ride this year I noticed the surge was much less and getting better, at 45 BMPH.

Might want to check the CVT belt, it might be slipping due to wear, dust, or oil.

Rode it on the freeway today, humming along great. Must have been some bad gas.