449/511 retard the timing with PCV at low RPM... Flameout Theory...

Mine is still hard to start on 'warm start' - hot or cold is fine, but if you start it cold, ride around the yard for 3 minutes and then shut it off and try to start it, cranks forever.

Hot/warm starts in general, sometimes it will pop right off other times it takes a touch of throttle. It’s inconsistent, I started my bike 30-40 times on a 350 mile trip both hot and cold. My buddies G450X starts instantly every time, he makes me mad lol.

I had it not start on me a couple times when I probably was too aggressive with the throttle. I waited 20-seconds for the bike to power down, tried it again and it fired right up. Embarrassing when out of 10 guys in the group, yours is the only one that didn’t start. Had a few “need a can of ether?” comments lol.

As inconsistent as it is, it almost has to be a tune issue or something that the ECU is seeing. Possibly timing? I will try messing with the tune a bit and see what I can come up with.

Adding the PCV and additional fuel in the low rpm's helped a lot, but it’s still not perfect. I have an Earthx battery by the way, so cranking speed isn’t the issue.

I've had hot start challenges and is one of the reasons which prompted me to invest in a manual choke. But I believe that all these issues are related to fueling. I now believe that the dead throttle issue is due to under population of the upper oem mapping and not a mechanical issue at all.

Every time a flame-out has happened to me is when I’m coming out of a ditch or whenever I was quick on the throttle to get the front wheel off the ground. Seems as though the FBW butterfly is just slow to react at times. Now on the contrary, I haven’t had a flameout yet after adding the PCV (Zipty Factory Map, 4-5% fuel from 1500-2500 RPM, Idle set at 2000 RPM) so I feel that fuel does play some role in the issue. Not saying my bike is cured, but it definitely did improve it.

WOW! ! That makes a lot of difference!
Need to rethink how much I've adjusted it.

Listing what I experienced here for reference.

When I had dead throttle issues, I found if I continued to hold the throttle above idle & not let it return, it would remain'dead'. Giving perhaps 50% power, barely enough to climb a short hill I was on the last time it occurred. As it was climbing I rolled the throttle back & forth between full & half with no change in engine power or rough running.
As soon as I closed it to idle & reopened it, power was restored. I was convinced then that the FBW had remained closed, resynced itself when I idled off again & returned to normal.
I also firmly believe too that the reverse is true of the hanging idle.
This happened very frequently, so I got plenty of chances to try different things. If I pulled the clutch, it would drop after a short delay. If I was trying to engine brake down a hill, Pulling in the clutch was sometimes the only way to drop engine revs.

Nope, not since the mod.
My own bike wasn't as bad as that, maybe once every few rides, but still very disconcerting.
As I posted elsewhere, I can't see how it will happen with the flap out.
Time will tell for sure as you say.

I don't see how it could be the injector, if you had the air needed for the power you asked for & the injector mis-fired, got the wrong signal etc, the fueling would be incorrect for the air & it would run badly, hesitate or miss, pop or something.
We are seeing how much as little as 5 or 10% makes to maps here....

In my instance, running was completely normal (smooth) except for the fact that I had 100% throttle, & only 50% power.

My thoughts anyway.

I think the FI\Tuning-mapping is all subjective on these bikes. We do know that they're definitely finicky. My primary concern has always been flameouts. Power has never been an issue as it has always had more
than enough power for the trails. I've tried all the different maps at some point most recent being the Schoops map which has reaffirmed my theory that what might work great for one bike (same bike, model,year etc..) may not
work great for another given all the little x factors that come in to play such as mods, elevation, atmosphere etc.. For me the best combo for having my 511 run right with the best power has been using the map that Aaron(BHP)
created with his dyno as my basemap with Tinken's ignition map....but running that setup with Auto Tune is what created my own ballistic missle. I'm not sure what to call it but I feel like the AT is probably the smartest map creator
of all.
In regards to Huskylove without question he will know more about his bike than Aaron, I mean the man is an innovator in the motorized bicycle industry(if memory serves) and, like Aaron, is a young business owner so they've got a lot
in common. My advise would be to give BHP a call (916)334-1238 and let him know what you want to do and I'm sure you guys could work together on the dyno. He's a cool guy and it's usually just him and his dog there, occasionally his wife.
I know it's a bit of a drive and I'm not sure if he works weekends. Maybe by appointment. If you do call him tell him Jerry sent ya.

Sounds like that is where I need to go for some dyno time. Did you eove the flap jerry? It is totally reversible if it foes not work for you.

Let me know when you go. I'd like to take time off work just to come and watch.

The butterfly does not create a "Pop" or a "stall" which is created by the the air increasing to the point of detonation, not the air getting cut off by a butterfly.

I can tell you that when the flywheels start to shear the woodruff keys on the x-lights that is exactly what happens.

The timing advances and the bike kicks back.