WR250F AIS disable?

[PoCoBob]

I have a 2012 WR250F and I just ordered a JD jet kit for it. I was told the kit works best if the AIS has been removed from the bike, but Yamaha doesn't make the removal kit anymore and the cheap fix that is part of the sticky thread involves using a Dorman 555-106 freeze plug. That plug seems to have been discontinued as well. So my question is can you disable that thing and still leave the water line still attached where it is? I really don't know how that thing works but I was thinking if I removed the vacuum hose and put a plug where it goes into the cylinder head and another plug where it attached to the AIS valve wouldn't that disable it? Any insight would be appreciated. 

 

Edit: What I am thinking is removing part #14 in the picture and capping both places where it was attached to. 

Edited December 17, 2020 by PoCoBob

[cmacwr]

I did this a few months back. Basically just removed all the pipes, tubing, pump, etc and capped the lines with high temp rubber caps. I can send a pic later if you need it. 

[William1]

AIS (Air Injection system) does not affect jetting or performance. Removing it disposes a little mass of parts and half a pound. Removal also decreases decel popping ever so slightly.

Hose Num,14 is a vacuum hose, not water.

[PoCoBob]

Thanks guys, I know #14 is a vacuum hose, that is where I'm assuming the air is injected into the engine and removing it and capping the ends would disable the system. But if there's no gain in performance I'll probably just leave it as is. The weight saving is something I would never notice. 

[cmacwr]

In case you decide to do it. 

[William1]

11 hours ago, PoCoBob said:

Thanks guys, I know #14 is a vacuum hose, that is where I'm assuming the air is injected into the engine and removing it and capping the ends would disable the system. But if there's no gain in performance I'll probably just leave it as is. The weight saving is something I would never notice. 

The air is injected into the exhaust, diluting it.

The vacuum hose operates/runs the air pump, drawing air in from the air boot and pumping it in to the exhaust.

[Allen Day]

Just to add to the comments. I've been rocking AIS on a dirt bike since 2010. 600+ hours later, and not a single problem. There is no real reason you can't delete it if you want, but you'll never notice while riding. This is especially true if you have a reasonably quiet exhaust. 

[PoCoBob]

Thanks, like I said in my first post I don't really understand what this thing does. Why I thought of this to start with is the removal kit that Yamaha made most of the parts in it were carb rejetting pieces. I assumed removing the AIS meant you had to rejet the carb so thinking in reverse if I rejet the carb I should remove the AIS. 

Edited December 18, 2020 by PoCoBob

[William1]

1 hour ago, PoCoBob said:

Thanks, like I said in my first post I don't really understand what this thing does. Why I thought of this to start with is the removal kit that Yamaha made most of the parts in it were carb rejetting pieces. I assumed removing the AIS meant you had to rejet the carb so thinking in reverse if I rejet the carb I should remove the AIS. 

Its' purpose is exhaust emissions and passing environmental regulations. In the old Yamaha GYTR 'race kit', removal was because the intention was for race bikes and it was part of lightening and simplifying things.

For example in California, some of the 'inspectors' know a WR has AIS and they look for and expect to see it. So owners cannot remove it. Some disabled it (to reduce decel popping) buy shoving a single ball bearing in the vacuum tube, blocking it.

[PoCoBob]

1 hour ago, William1 said:

Its' purpose is exhaust emissions and passing environmental regulations. In the old Yamaha GYTR 'race kit', removal was because the intention was for race bikes and it was part of lightening and simplifying things.

For example in California, some of the 'inspectors' know a WR has AIS and they look for and expect to see it. So owners cannot remove it. Some disabled it (to reduce decel popping) buy shoving a single ball bearing in the vacuum tube, blocking it.

Good stuff! That explains a lot. When I first started thinking about this I downloaded the instructions for the GYT-5UM-69-01 kit, even though it's no longer available, just to see what all was involved. Those instructions also explain how to remove the airbox snorkels, the exhaust restrictor and unplugging the grey wire. I see now that it really was a "race" kit, just not called one. 

Hopefully my JD kit will arrive before things shut down for xmas and I'll have something to work on over the break. 

[William1]

33 minutes ago, PoCoBob said:

Good stuff! That explains a lot. When I first started thinking about this I downloaded the instructions for the GYT-5UM-69-01 kit, even though it's no longer available, just to see what all was involved. Those instructions also explain how to remove the airbox snorkels, the exhaust restrictor and unplugging the grey wire. I see now that it really was a "race" kit, just not called one. 

Hopefully my JD kit will arrive before things shut down for xmas and I'll have something to work on over the break. 

Very welcome.  I put a on/off switch on my grey wire. On the 'WR' setting, it softens the 'hit' a little bit, making severe mud riding a little easier for this 'olde guy'. I very rarely make use of it but it is nice to have the option. You cannot switch on the fly, the bike has to be shut down, then flip the switch then restart. Not a big deal. I believe the JD kit covers the snorkel removal too..

I put my switch in the airbox.

 

 

[Ruggage]

7 hours ago, William1 said:

Very welcome.  I put a on/off switch on my grey wire. On the 'WR' setting, it softens the 'hit' a little bit, making severe mud riding a little easier for this 'olde guy'. I very rarely make use of it but it is nice to have the option. You cannot switch on the fly, the bike has to be shut down, then flip the switch then restart. Not a big deal. I believe the JD kit covers the snorkel removal too..

I put my switch in the airbox.

I was so impressed with your location William1, had to do the same. It is my son's bike now and he does not see the value in the switch as  he says he will never go back to WR mode (of course he's 16). I still think it could be useful one day.

We did the mods mentioned: snorkel, jetting, exhaust restrictor, and as mentioned gray wire mod. Really brought the bike to life! Don't forget the throttle stop and o-ring mods.

Edited December 19, 2020 by Ruggage
misspelling

[TacticalBrad]

 Just picked up the 2012 WR250F and so far it is much different that all the other pics/video to remove AIS so I appreciate this thread and the pictures. I think I have identified the parts and since the kits aren’t available anywhere anyone remember  the size of the caps.... 

more pictures of what I need to cap on this model/year are appreciated. I am do the switched grey wire mod also since why not. 

Edited Thursday at 01:36 PM by TacticalBrad

[Jens Eskildsen]

This is a wr250F subforum

 

Try here: https://thumpertalk.com/forums/forum/510-wr250rwr250x/

[TacticalBrad]

4 hours ago, Jens Eskildsen said:

This is a wr250F subforum

 

Try here: https://thumpertalk.com/forums/forum/510-wr250rwr250x/

Must have fat fingered it... mine is an F