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I've been searching through the sub trying to find anything that matched my problems and have had no luck. I bought a 2015 r3 with 15k miles and everything has been great. I've put a thousand miles on it so far with no issues at all. However the other day i was riding to work and I suddenly lost acceleration. I was going 65 and the bike was still on but was slowing down even after downshifting and under full throttle, so I eventually puilled off and turned the bike off. After this the bike starts briefly under full throttle but dies right out. I've checked fuses, tested my injectors and they work fine and my fuel pump even primes when I turn on the ignition. Spark plugs are brand new as I changed them when I bought it. I'm out of ideas to tests and ould appreciate some help, thanks!
 

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A sudden loss of power on the R3 is normally associated with a loose battery terminal connection. I'd start by looking between the positive battery terminal and the connections going to the starter solenoid assembly. You'll need to remove the front seat and the center panel between the front and rear seats to get into this area. Examine any and all connections at the battery heading to and from the starter solenoid. Look for loose, corroded, or burned/melted insulation at the terminal ends.
Top center of this page has a "search community" that's helpful. I have one section listed below if you'd like to search .
Search results for query: battery terminals and starter solenoid | Yamaha R3 Forums (r3-forums.com)
 

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I just finished testing and I have spark on both plugs.
The principle is always the same. Suck, Squeeze, Bang, Blow. The bang comes from fuel/air/spark. In this case, it sounds like one of the two cylinders is not getting fuel.

If spark is good, you are missing fuel, so this is likely an injector not providing fuel. This can be from a loose injector wire connection, failed solenoid, or a clogged injector from fuel contamination. The next step is to test and evaluate the fuel supply side. To determine which of the two it is, disconnect the spark plug cap one at a time. If it still tries to start on one cylinder, that one is getting fuel, and it is the disconnected cylinder with the issue. If it no longer tries to start, than the disconnected cylinder is the one not getting fuel. Check the connectors, and wires to the injector first. Then, pull the injector and have a look. If you try to start the bike with the injector out, it should spray fuel. If not, it is likely fouled and will need to be cleaned or replaced.

This video shows the process of checking the injector system on Yamahas. Note that he references the self diagnostic mode, which does not exist on the R3. The fact that you are not seeing an error code (which will appear in the odometer display area when active) on the dash display, or check engine light, is an indication it is probably an issue with a clogged or failed injector, rather than an electrical fault that the ECU would sense.

 

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Another case of a problem with no posted outcome. This was either a bad injector or a failed ECU. The bike was attempting to start on one cylinder, with no error codes. The issue is most likely hardware. Anyone else have this issue that was resolved? The OP obviously can't be bothered.
 
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