SLIP ON NO PROGRAMMER?

recently purchased a new wr250r, its way to quiet so i was going to add a slip on exhaust. i was told that i would be fine with a slip on and no programmer. just seeing if anyone else is running a slip on and no programmer? thanks

Yeb, fine.

brandonjb09 wrote:

recently purchased a new wr250r, its way to quiet so i was going to add a slip on exhaust. i was told that i would be fine with a slip on and no programmer. just seeing if anyone else is running a slip on and no programmer? thanks

You must be young and still have most of your hearing!  LOL

The bike will run fine with a slip on however you will set the Check Engine Light (CEL) when you disconnect the stock exhaust and EXUP valve.  The EXUP valve is located in the stock muffler assembly and closes off the exhaust at low RPM small throttle movements for an increase in torque and some say a decrease in noise level.  I myself went with the slip on route early on and then went back to stock mainly because I like the little torque bump you get from the EXUP when riding through some tight stuff.  However, many will disagree with that statement - but what the hell it is my bike and I will do what I want to do to it.  

In order to get the CEL not to come on you there are a couple of things you can do:  

- Buy an EXUP emulator that you plug into the circuit instead of the EXUP motor (http://shop.12oclocklabs.com/index.php?route=product/product&product_id=94)
- Leave the EXUP motor on the bike but just disconnect the cables that actuate the EXUP valve
- Do the DIY Cheap EXUP Servo bypass mod (https://wr250rforum.forumotion.com/t627-cheapest-diy-servo-bypass)

The other thing you may notice when you ad the slip on is some exhaust popping on DECEL.  This will be due to the AIS system injecting air into the exhaust gasses to help the catalytic converter (which is part of the stock muffler assembly) burn off the unburnt hydrocarbons from the engine.  Since the catalytic converter is gone these are no longer burned off in a controlled manner and instead will generate little pops (sort of like small backfires) in the exhaust system.

You can either remove the AIS system and make or buy a block off plate for the injection port or just leave it alone and put up with the popping noise.

brandonjb09 wrote:

recently purchased a new wr250r, its way to quiet so i was going to add a slip on exhaust. i was told that i would be fine with a slip on and no programmer. just seeing if anyone else is running a slip on and no programmer? thanks

I just picked up a new 2016 and first thing I did was install a FMF pipe and the header including removing the EXUP. I ordered the part to remove the check engine light. I just put on 3000km (1860 miles) offroad through Utah and Colorado with elevation changes from Sea level where I live to riding Utah a 5000 feet to 11000 feet going through Ophir pass in Colorado. I kept the spark arrester in to quiet the pipe and give more bottom end. I had full luggage 100lbs and me at 200 lbs with stock gearing. It performed awesome in my opinion and the only area I thought it was having issues was at the top of Ophir pass where I think it wasn't getting enough air. It maybe had a little popping on de-acceleration one or 2 times, and it wasn't that bad.
You'll be all good with it
I just yesterday put on the EJK fuel mapper and trying it out. It feels like it has a bit more jam.

you can do the TPS mod. it will richen it a little and run better, do a search its easy I used a 2ft, long 3/8 extension to tap it. the wrr does need some back pressure for lowend, I keeped my exup and put slip on after the exup. now I just got the yz250fx what a machine, now just trying to get a tag for it