Hi,

I’m about to buy a 4rt. How are people cleaning the fuel injection throttle body. Is it similar to a carb where you use carb cleaner or an airline to clean it out after a ride?

The throttle body does not need cleaning, that is the air filter's job.  Or are you talking about the outside of the TB?

Just an update on this. I’ve had my 4rt bought new for about a year. The inside of the throttle body does in fact need cleaning.

I’ve found the inside of the body, around the butterfly value had a light coating of oil. This is either air filter oil residue sucked from the filter, blowback from the engine (I guess that’s why the air filter has a fire proof mesh) or both.

I easily cleaned this out with carb cleaner. As a note DON’T DO THIS! The solvent in carb cleaner affects the throttle body air pressure/temp sensor. It was a bitch to start at my next trial until I flushed enough air through the throttle body.

Use specialist throttle body cleaner, which is designed not to effect the sensor. 

Oil won't hurt the throttle body.  The fuel injector is after the throttle body and that is where fuel residue would start to be apparent, if anywhere.  Race fuel is a very aggressive solvent if you have been running poor quality fuels and will be going through the injectors.  Crankcase ventilation is critical to preventing oil going places it should not, like past the intake valve seals for example.  Spray solvent can dissolve the blue silicon insulation inside the main electrical connector, use only air if it gets water condensation in it. 

If any flame gets past the 4-stroke valves the filter could ignite unlike the 2-stroke 315 model, hence the addition of a flame screen is required.

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