Does it have spark?
How strong is the fuel pump working?
Is the injector spraying clean?
What is your valve clearance?
It's pretty hard to diagnose an electrical problem over the internet, let alone on vague information. My best advice is to get your electrical meter and service manual out and use the troubleshooting section to test everthing. It's a long, tedious process but this is why shops charge alot of money for problems like this.
You can check the injector by looking through the throttle body with the throttle open while someone kicks the bike to see if it is spraying. You just have to remove the subframe, take the ECU out of the subframe obviously and plug it back in to the harness.
Make sure you don't try putting a 12v power source to the injector to test it if you dont check by kicking the bike. It operates with 5v and you will ruin the injector if you put too much voltage too it.
Did you test compression? Did you do a leak test? 4 strokes need good compression, fuel, air, and timing to run. Check your major things first and work down from those.
When did this issue start? How did the bike act when it first happened? Were you already riding or was it at the beginning of a ride day?
Answering some of those questions may help us help you get your bike starting!
ST.HILAIRE MOTORSPORTS- New Englands #1 Motocross Race Shop
SHIP US YOUR ENGINE FOR FAST, RELIABLE, QUALITY SERVICE
Mention Vital MX for 10% off all engine rebuilds
It sounds more like a valve train and/or timing issue
Sounds like a timing issue, you may have got it a tooth or two off on the cam sprocket.
On the cam sprocket you have an arrow that should line up with the flat surface of the head, also you have 2 marks on the stator side visible thru the timing plug, and another mark on the clutch side visible thru another inspection plug. The 2 on the stator side are a fire mark and a timing mark the mark on the right of the 2 needs to be lined up with the mark on the case. This all needs to be done on the COMPRESSION stroke not the exhaust stroke.
I would pull the plug and use an allen head tho turn the motor over thru the inspection hole on the clutch side, check to make sure all marks line up. The cam lobes shouldn't be touching the buckets and that will let you know your on the compression stroke at top dead center. If you not sure about TDC get a screwdriver and put tape on the end (protect piston from scratching) and put it down the spark plug hole, watch for it to reach it's highest point and that should be TDC. DO NOT KICK IT OVER WITH THAT SCREW DRIVER DOWN THE HOLE, turn it over by hand. Hope this helps.
You're trying to use logic in your post and 4stroke doesn't appreciate logic! (FACT)
You need three things for a bike to run 1. Air, 2. Spark, 3. Fuel. I agree it sounds like a timing issue to me.
I hate to admit this, but make sure there isn't a rag in the air box blocking air getting to the motor.
If you need Prototypes/3D Printing-Mechanical CAD Design-3D Laser Scanning-Please support my business 3DProtoPrint.com. I give Vital Memebers 10% off.
My 2011 250R is still in the shop (been over 3 months now), had the same problem: hard starting, would bump-start fine but impossible to kick. Rebuilt the motor, still wouldn't start. Problem now traced to the fuel injection electrical circuit (fuel pump was only putting out 12 psi fuel pressure), issue with ground fault in the voltage regulator/capacitor. Bike starts fine with 12V battery connected to fuel pump that provides 48 psi as per spec. Will keep you posted...
You also might double check the fuel pump filter to se if there is a blockage or if is dirty.
The 2010 had issues with the fuel filters and the fuel pump. Both have been updated by Honda. If yours has not been updated it could be one of your issues. We were replacing fuel filters constantly on the 2010 until we upgraded to the new pump and filter.
Thanks for the help guys. Right now the injector & fuel filter is being replaced.
According to Honda they have had issues with the fuel injectors, which are fickle and small amounts of dirt & contaminiation prevent fuel pressure buildup during starting. It gets so bad that the fuel pressure bleeds off in less than 10 min, and after successive attempts kicking the unburnt fuel not only floods the engine, but can wash down the cylinder and wash the oil out of the left crank bearing causing it to fail on startup (especially because everyone rev the shit out of their bike to "clean it out"!).
Recommendation from large aftermarket parts supplier FOR ALL FUEL INJECTED HONDA DIRT BIKES is to install an in-tank micro cloth mesh screen on the fuel tank filling cap to prevent dirt entering tank from fuel filling.
Should have installed the tank screen from new, & listened to my "know-it-all" buddy!