New owner needs help!

Bought a 2009 WR250X two days ago. This morning it went to Jett Tune and will get a PC and a dyno session this week. My quesion is concerning the intake side of things. I have read about several mods to the airbox and am concerned I should do these before the bike rolls into the dyno room.

Advice is greatly appreciated, thanks.

Slideways wrote:

Bought a 2009 WR250X two days ago. This morning it went to Jett Tune and will get a PC and a dyno session this week. My quesion is concerning the intake side of things. I have read about several mods to the airbox and am concerned I should do these before the bike rolls into the dyno room.

Advice is greatly appreciated, thanks.

The only reason I would do something like this is to have a baseline of where I started from.

Once you mod the bike I would think you would want another Dyno session to map the fuel correctly unless you have something like Autotune on the bike. Even then I would think you would want to verify that your optimal A/F ratio has not changed.

Slideways wrote:

Bought a 2009 WR250X two days ago. This morning it went to Jett Tune and will get a PC and a dyno session this week. My quesion is concerning the intake side of things. I have read about several mods to the airbox and am concerned I should do these before the bike rolls into the dyno room.

Advice is greatly appreciated, thanks.

Is your bike 100% stock?

If not - what mods have been done to it?

Why are you getting a PC and a dyno tune?

Especially if you know next to nothing about opening up the intake side of things?

There's too many questions unanswered from your side of things to give you much feedback.

We need more details.

What do you have, and what do you want?

You are right, did not provide much info. There is a GYTR exhaust and the stock ECU is in a box with all the rest of the original bits. I assume a different ECU was installed but know only that it is not a Power Commander or FMI. Lower flow air filter in place of stock. That is it.

Main concern for me is that I do not want to dyno the bike again and again. If air box mods are worth it I should take care of those before John dynos my new ride.

If you're looking for peak performance then do the airbox mods.

If you're not riding in sandy or very dusty conditions you might just consider removing the airbox door, rather than cutting holes in airbox or other destructive options.

Just to be clear - an EFI unit like a Power Commander 5 or 3, or an FmF type unit does not replace the ECU.
They work in conjunction with the ECU.

Not sure what you mean by stock ECU is in a box.
I'm not aware of replacement ECU's other than OEM factory Yamaha replacements.

Pictures are worth a million words here.   

If you do live in dusty conditions you may want to make sure the flapper is removed from the airbox (my guess is that the PO has done that) and replace that hi-flow airfilter (K&N ?) with a more standard foam and oil filter to keep dust out of the motor.

Pictured here is what I found in the box of original parts. I am assuming it was replaced with a GYTR part. My preference would be something that allows control of both air/fuel and ignition.

I have no friggin clue what that thing is.

Best guess at this point is that is some kind of EXUP servo eliminator module thingy.   


I know it's not the ECU though.

Looks like the EXUP servo motor.