Help 2010 crf250r wont run

[cbtaylor8893]

My 2010 crf250r won't run when the motor is mounted onto the bike. I changed the fuel pump and the injectors. The motor will run when it is sitting on a table or motor stand. But when I put the motor back on the bike it will not run. What could be wrong?

 

[Rich Rohrich]

Need more facts for anyone to be much help.
You need the following to make it run, and a couple of those are fixed and won't change in or out of the bike:
Fuel
Air
Compression
Timing (Ignition and Cam)
Spark

Which of the above are you missing once the engine is in the frame, and how are your electrical grounds changing between the two setups?