RM-Z250 2015 RMZ 250 won't start

I get one interesting problem. First I tune voltage on throttle position sensor. It should be 0.68-0.72v at idle. When I open throttle several times and get it back voltage becomes more or less than normal. After that engine makes pops&bangs or even shut off and I can't start it. I'm sure that there is a problem with gas handle. Look at the part number. Suzuki updated position 1 and position 2 on the picture
As part of my never-ending rebuild I replaced the throttle tube that the image is referring to, I'm not sure how that would relate to the problem you describing but its a 10-minute job and the actual part is really cheap so to replace that isn't going to set you back majorly. I put the link below to the vid I followed, maybe watching him do it and checking yours, you can fault find, before buying a new throttle tube. Hope that helps

https://www.youtube.com/watch?v=Yi5jR7zEOoE
 
Here are the specs for your bike.
I would start testing any of the values that you can in the Electrical and FI section, especially the CKP sensor.
 

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With my low hour 2013 rmz250 which has a new piston and rings, valves in spec, new plug, etc.... I'm having serious starting issues here as well it takes a minimum of 20+ good solid t.d.c. stroke kicks when its cold as well as an it on rare occasion having an issue of it not wanting to start after I kill it or when it dies for no apparent reason. Everything I've been reading is unfortunately telling me its the ecu re-mapping Suzuki did due to a factory recall in 2013 over kickbacks while starting that was damaging bikes by breaking internal starter gears and clutch baskets etc.. so Suzuki changed the timing, made the replacement ecu to not fire on the exhaust stroke as it previously did, as well as some other changes during starting (or killing yourself attempting to!) that now cause the 2013-2015 to be extremely difficult to cold start etc... so instead of properly solving the kickback issue they caused a serious starting issue to solve the kickback problem! From what I've read the only sure fix is getting an aftermarket Vortex brand ecu for the bargain price of $700 guess I'll be kicking the hell outta this thing every time I want to ride, tow starting it, or building a roller starter. Wish I would have known all of this before buying this p.o.s. because I'd be riding a Honda, Yamaha, Kawasaki, or KTM. The Suzuki dealership couldnt fix it here in the St Louis area either so I just wasted a few hundred $ there that could have went toward the frigging $700 box! Oh also it runs excellent once you get it warm and usually restarts easily with a single weak kick even if you don't bring it up to t.d.c.!
 
With my low hour 2013 rmz250 which has a new piston and rings, valves in spec, new plug, etc.... I'm having serious starting issues here as well it takes a minimum of 20+ good solid t.d.c. stroke kicks when its cold as well as an it on rare occasion having an issue of it not wanting to start after I kill it or when it dies for no apparent reason. Everything I've been reading is unfortunately telling me its the ecu re-mapping Suzuki did due to a factory recall in 2013 over kickbacks while starting that was damaging bikes by breaking internal starter gears and clutch baskets etc.. so Suzuki changed the timing, made the replacement ecu to not fire on the exhaust stroke as it previously did, as well as some other changes during starting (or killing yourself attempting to!) that now cause the 2013-2015 to be extremely difficult to cold start etc... so instead of properly solving the kickback issue they caused a serious starting issue to solve the kickback problem! From what I've read the only sure fix is getting an aftermarket Vortex brand ecu for the bargain price of $700 guess I'll be kicking the hell outta this thing every time I want to ride, tow starting it, or building a roller starter. Wish I would have known all of this before buying this p.o.s. because I'd be riding a Honda, Yamaha, Kawasaki, or KTM. The Suzuki dealership couldnt fix it here in the St Louis area either so I just wasted a few hundred $ there that could have went toward the frigging $700 box! Oh also it runs excellent once you get it warm and usually restarts easily with a single weak kick even if you don't bring it up to t.d.c.!
My buddy has a ‘15 450 does this issue crossover to his bike? Or only the two fiddys?
 
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